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"brake" Warning Light Dimly Illuminated


90LS400Lexus
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It obviously just started today, or I would have noticed it last night, but this evening on my drive home from work, I noticed that the "BRAKE" warning light was "DIMLY" illuminated. Brakes feel fine, perfect really. I got home and depressed the emergency brake and it lit up brighter like it should, but when I took the emergency brake back off, the light stayed illuminated a little.

Does anyone have any clue as to what this could be? No other lights are illuminated. Could it be the wires at the trunk hinge (which appear to have already been worked on), or a bad brake sensor, or???? Possibly the rear brake pads are wearing down? I am not sure what all functions this light supposed to signify.

I was supposed to give this car to my mother tomorrow and now this happens.

Thanks for any help. BTW - its a 1991 LS400.

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It obviously just started today, or I would have noticed it last night, but this evening on my drive home from work, I noticed that the "BRAKE" warning light was "DIMLY" illuminated. Brakes feel fine, perfect really. I got home and depressed the emergency brake and it lit up brighter like it should, but when I took the emergency brake back off, the light stayed illuminated a little.

Does anyone have any clue as to what this could be? No other lights are illuminated. Could it be the wires at the trunk hinge (which appear to have already been worked on), or a bad brake sensor, or???? Possibly the rear brake pads are wearing down? I am not sure what all functions this light supposed to signify.

I was supposed to give this car to my mother tomorrow and now this happens.

Thanks for any help. BTW - its a 1991 LS400.

TRY CHECKING THE BRAKE FLUID LEVEL!! IT HAPPENED TO ME ONCE AND I FOUND OUT THE LEVEL WAS JUST UNDER THE "FULL" LINE.

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My theory? Your alternator is on the way out. I think this is the precursor of strange electrical idiot light behavior that accompanies alternator failure. I had this dim parking brake light/low brake fluid light for a while, couldn't figure what it was indicating. I kept an eye on brake fluid level which was always fine. There is another idiot light for brake pad wear. It was a little while before the alternator failed so you have time to locate a rebuilt. Replacing is straight forward. Maybe a Sears will check the charging system for you.

glenmore

1990 LS400

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Sounds lovely. Of course when I decide to let her have the car, it wants to start falling apart. <_<

Checked the fluid and its full. :(

Thanks

My theory? Your alternator is on the way out. I think this is the precursor of strange electrical idiot light behavior that accompanies alternator failure. I had this dim parking brake light/low brake fluid light for a while, couldn't figure what it was indicating. I kept an eye on brake fluid level which was always fine. There is another idiot light for brake pad wear. It was a little while before the alternator failed so you have time to locate a rebuilt. Replacing is straight forward. Maybe a Sears will check the charging system for you.

glenmore

1990 LS400

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Its a Lexus thing.. All the models have this feature but its not listed in the book. Its saying the fluid is down but also check brake wear.

Thanks, well the fluid is full. Not sure about the brake pads though, because they have been squeaking lately. The PO said they had not been on there too long before I bought it, but it had 207K and now it has nearly 214K. I guess 7000 miles has went by, so its possible.

Glenmore said there was a seperate light for brake pad wear, but I have never noticed it come on during "bulb check". Odd, but I have never even seen a "brake light out" warning light and I know I have one of those out. ALL of the warning lights seem to be working.

I would be so relieved if it was just the pads wearing down.

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The brake pad warning indicator is a separate light. That feature did not start until the 1993 model year. 90-92 LS400s do not have a brake wear warning light.

I'll second Glenmore's comment about the alternator beginning to fail. Over the past few months, I started having similar problems with my 92 LS. The alternator failed because it had gradually become saturated with power steering fluid from a leaking pump. It sounds to me like you are having the same problem I did. I wouldn't trust the alternator tester from Sears, AutoZone, etc. They tested mine twice and said it was "OK".

I purchased a replacement alternator and power steering pump at O'Reilly's Auto Parts. Both parts only cost me $280. They were remanufactured and came with a lifetime warranty. I normally do not care for non Toyota-genuine parts, but these parts were pulled from another LS400, and then had been remanufactured. They were identical to the Toyota-genuine ones currently in my car.

Normally, I probably would have installed the parts myself. However, at the speed I like to work, I decided it would be easier to pay someone else to install them for me. I took the car to a local independent Lexus mechanic and gave them the parts to install. Altogether, the repair including parts cost me about $600.

If you continue to drive the car, hook it up to a battery charger when not in use, carry a portable jump starter in the trunk, and just be careful. My car's engine died a couple times during the time I was driving it with the failing alternator. The LS400's electrical system is not designed to operate without a battery, and the battery will quickly become drained when the alternator is not functioning properly. Between the warning lights, and flashing instrument cluster, the car will give you plenty of notice before the engine is about to shut off.

All this information is based on my experiences. In order to avoid wasting money replacing unnecessary parts, I think the best thing to do would be to take the car to a Lexus dealership or independent mechanic and have them diagnose the problem for you. If I can't figure out a problem myself, I like to have my car diagnosed by someone who is familiar with the LS400's common problems. That way, I can ensure I get an accurate diagnosis. If you don't have a mechanic specializing in Lexus cars, I think it would be a job for the dealership.

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chances are that the spring in the ebrake lever is starting to fail, causing the peddle itself to sag. this is very common on older cars. mine did this too, every morning. try this....with your toe behind the ebrake peddle, pull the lever up. see if that turns off the light. obviously hold the ebrake release while doing this....

not bad for my first posting on my wife's new wii!

1 thing to try to remember on these cars, is that they're so dang good that the easiest fix almost doesn't seem right, and easily overlooked. a lesson i had a very hard time learning myself, until i hit the $3,000 mark in repairs...which just sucked!!!!!

the pad light looks like the following, or close to it.... "(Δ)"

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Yes, try the lifting of the brake pedal with your left foot while releasing the parking brake but this didn't work for me.

My problem was just a worn out alternator that took a while to fail. If your alternator is dying from the "p/s fluid bath", it could go quicker.

I found an ebay seller that happened to be local and IIRC it was less than $100. Lots of them on ebay. If you DIY, take the heat shield and any other attachments off your alternator before sending it in if they want core.

As Thomas said, and as I experienced, next up is a dead battery. My battery was due, so I thought I just needed a new one. Put the new one in and it wasn't long before all the lights would come on and thankfully I finally noticed the charging idiot light.

There is a general "lamp out" idiot light. Mine comes on more than I think is normal, always a taillamp. Sometimes I need a new bulb, sometimes the bulb just needs a tap.

glenmore

1990 LS400

1991 300CE

2000 C280

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Thanks.

Well, I tried pulling up on the e-brake pedal with my foot, thinking that was the problem, but it was not. Its all the way up. I was hoping that was it... I had that problem with my old 85' Mercedes.

Just fine.. it sounds great about the alternator and PS pump. $280 is not pocket change to me, especially since I was going to soon shell out $400 for new motor/transmission mounts which it also needs (and it would not even be my car anymore). OMG, this car is costing me a fortune. I guess I will dig even deeper into my savings account and invest $600 more into a new PS pump and alternator. One would think there would be a recall on this well-known design flaw, as well as that dang trunk hinge wiring issue.... especially since Lexus knows this is a widespread problem that could have been prevented.

The PS is losing fluid in the winter, but there are no leaks under it that I can see. The alternator looks dry. I was assuming it was leaking internally, because I have that little white smoke on startup in the winter months (and its not the steam from the temperature). It stays full in the warm weather months.

What kills me is that this just started this - ONE day before I was giving it to my mother, because her car is a POJ and I wanted her to have this "reliable" car and now I cannot comfortably hand over the keys and say go for a dependable ride. :rolleyes: At least her Oldsmobile does not have a leaky PS pump or faulty alternator. <_< What will be next to go wrong after I spend about $800 on these repairs (PS pump, alternator, mounts)? She really loves this Lexus and I just wanted to sell it. Maybe I can gently break the news about its issues and sell it and buy her something else? Its always something to agitate me. I guess I will bite the bullet and replace things on it as needed and take out a small loan on repairs or dig into my savings account.

I am hoping I can get the alternator rebuilt pretty cheap at that local machine shop and if it is the PS pump leaking and causing it, maybe I can get the pump repaired - (whatever leaks on these dang things). Maybe it will not cost a blooming fortune. If it is the PS pump leaking and causing it, what does it typically destroy? Brushes? Resistors? Regulator? All of the above? The entire alternator?

Oh well. Thanks for the replies.

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Thanks.

Well, I tried pulling up on the e-brake pedal with my foot, thinking that was the problem, but it was not. Its all the way up. I was hoping that was it... I had that problem with my old 85' Mercedes.

Just fine.. it sounds great about the alternator and PS pump. $280 is not pocket change to me, especially since I was going to soon shell out $400 for new motor/transmission mounts which it also needs (and it would not even be my car anymore). OMG, this car is costing me a fortune. I guess I will dig even deeper into my savings account and invest $600 more into a new PS pump and alternator. One would think there would be a recall on this well-known design flaw, as well as that dang trunk hinge wiring issue.... especially since Lexus knows this is a widespread problem that could have been prevented.

The PS is losing fluid in the winter, but there are no leaks under it that I can see. The alternator looks dry. I was assuming it was leaking internally, because I have that little white smoke on startup in the winter months (and its not the steam from the temperature). It stays full in the warm weather months.

What kills me is that this just started this - ONE day before I was giving it to my mother, because her car is a POJ and I wanted her to have this "reliable" car and now I cannot comfortably hand over the keys and say go for a dependable ride. :rolleyes: At least her Oldsmobile does not have a leaky PS pump or faulty alternator. <_< What will be next to go wrong after I spend about $800 on these repairs (PS pump, alternator, mounts)? She really loves this Lexus and I just wanted to sell it. Maybe I can gently break the news about its issues and sell it and buy her something else? Its always something to agitate me. I guess I will bite the bullet and replace things on it as needed and take out a small loan on repairs or dig into my savings account.

I am hoping I can get the alternator rebuilt pretty cheap at that local machine shop and if it is the PS pump leaking and causing it, maybe I can get the pump repaired - (whatever leaks on these dang things). Maybe it will not cost a blooming fortune. If it is the PS pump leaking and causing it, what does it typically destroy? Brushes? Resistors? Regulator? All of the above? The entire alternator?

Oh well. Thanks for the replies.

If you are losing fluid in the winter, it is probably being sucked into the intake manifold and burned through the 2 vacuum lines connected to the idle air control valve. That's another thing that was happening to my car. My mechanic removed the valve and installed a screw in it's place. Then capped off both of the connections for the vacuum lines. Now the speed-sensitive steering is a little bit "different", but he told me I wouldn't notice a difference, and I don't.

You may be able to get the alternator rebuilt, but if your problem is like mine was, it was totally saturated and not worth fixing. It is possible to rebuild the power steering pump, but with the relatively low cost of a replacement ($120), it doesn't make much sense. You don't get the lifetime warranty rebuilding it yourself, and it's difficult and takes a long time.

The pumps just start to leak eventually because the o-rings get brittle and crack. It's not at all unusual to be replacing components with rubber parts like mounts, hoses, power steering pumps, etc, on a 17 year old car. An alternator is not uncommon to have worn out at this age and mileage either. The good news is, it sounds like everything else on your car is working correctly. I would imagine this will be the last major repair you will have to make for a while.

But, before you go spend a lot of money on this repair, I think it would be worth the $100 to have a professional diagnosis done. That way you will not spend extra money replacing parts that don't need to be replaced. The power steering pump might not even be bad...it could just be the alternator, or not even that.

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Thanks.

Well, I tried pulling up on the e-brake pedal with my foot, thinking that was the problem, but it was not. Its all the way up. I was hoping that was it... I had that problem with my old 85' Mercedes.

Just fine.. it sounds great about the alternator and PS pump. $280 is not pocket change to me, especially since I was going to soon shell out $400 for new motor/transmission mounts which it also needs (and it would not even be my car anymore). OMG, this car is costing me a fortune. I guess I will dig even deeper into my savings account and invest $600 more into a new PS pump and alternator. One would think there would be a recall on this well-known design flaw, as well as that dang trunk hinge wiring issue.... especially since Lexus knows this is a widespread problem that could have been prevented.

The PS is losing fluid in the winter, but there are no leaks under it that I can see. The alternator looks dry. I was assuming it was leaking internally, because I have that little white smoke on startup in the winter months (and its not the steam from the temperature). It stays full in the warm weather months.

What kills me is that this just started this - ONE day before I was giving it to my mother, because her car is a POJ and I wanted her to have this "reliable" car and now I cannot comfortably hand over the keys and say go for a dependable ride. :rolleyes: At least her Oldsmobile does not have a leaky PS pump or faulty alternator. <_< What will be next to go wrong after I spend about $800 on these repairs (PS pump, alternator, mounts)? She really loves this Lexus and I just wanted to sell it. Maybe I can gently break the news about its issues and sell it and buy her something else? Its always something to agitate me. I guess I will bite the bullet and replace things on it as needed and take out a small loan on repairs or dig into my savings account.

I am hoping I can get the alternator rebuilt pretty cheap at that local machine shop and if it is the PS pump leaking and causing it, maybe I can get the pump repaired - (whatever leaks on these dang things). Maybe it will not cost a blooming fortune. If it is the PS pump leaking and causing it, what does it typically destroy? Brushes? Resistors? Regulator? All of the above? The entire alternator?

Oh well. Thanks for the replies.

"That ol ls magic has you in it's spell" :D - listen, I think NC is headed in the right direction. I would check the ebrake cable. If it's not lubricated very often it likely not releasing completely and causing your warning light to barely light up. One way to check is to drive for a while then stop the car on a level grade, then release the service brake and leave the car in neutral. If the car doesn't move, get out and push the car a few feet. Note how much effort it required to move the car, then get in and apply the ebrake as you would normally. Now release the ebrake (still in neutral) and repeat pushing the car. If you noticed a difference in how much effort it took to move the car a few feet, I would say your cable is sticking and not releasing properly. Good luck.

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Thanks for the replies guys. Well I drove the LS this morning and the light was still barely illuminated. I made a few stops and on the way back, I stopped and ran in the credit union and I applied the e-brake. I came back out, released the brake and the light was completely off and never came back on. (for now).

Hopefully it is just a loose cable. If not and the alternator goes out and its caused by the PS pump, we (or I) will have to deal with that when the time comes I guess. :(

Thanks again.

"That ol ls magic has you in it's spell" :D - listen, I think NC is headed in the right direction. I would check the ebrake cable. If it's not lubricated very often it likely not releasing completely and causing your warning light to barely light up. One way to check is to drive for a while then stop the car on a level grade, then release the service brake and leave the car in neutral. If the car doesn't move, get out and push the car a few feet. Note how much effort it required to move the car, then get in and apply the ebrake as you would normally. Now release the ebrake (still in neutral) and repeat pushing the car. If you noticed a difference in how much effort it took to move the car a few feet, I would say your cable is sticking and not releasing properly. Good luck.
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Thanks for the replies guys. Well I drove the LS this morning and the light was still barely illuminated. I made a few stops and on the way back, I stopped and ran in the credit union and I applied the e-brake. I came back out, released the brake and the light was completely off and never came back on. (for now).

Hopefully it is just a loose cable. If not and the alternator goes out and its caused by the PS pump, we (or I) will have to deal with that when the time comes I guess. :(

Thanks again.

"That ol ls magic has you in it's spell" :D - listen, I think NC is headed in the right direction. I would check the ebrake cable. If it's not lubricated very often it likely not releasing completely and causing your warning light to barely light up. One way to check is to drive for a while then stop the car on a level grade, then release the service brake and leave the car in neutral. If the car doesn't move, get out and push the car a few feet. Note how much effort it required to move the car, then get in and apply the ebrake as you would normally. Now release the ebrake (still in neutral) and repeat pushing the car. If you noticed a difference in how much effort it took to move the car a few feet, I would say your cable is sticking and not releasing properly. Good luck.

One last thing. I don't know if you use your ebrake regularly or not. Your problem could be caused by not using the brake regularly and then one day applying it a little too hard. You only need apply it with enough pressure to secure the car from moving. Obviously light pressure on an even grade adding more as the grade increases. This will keep the shoes/cable in good condition. As with anything, use it or lose it! :cheers:

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Actually, I never use that brake. I only applied it today to keep using it hoping if it was the brake causing it that me using it would help. Strange it (light) came on, because I had never used it. I guess it was sagging down or something. Drove the car several miles today and the light never came back on when driving. Hopefully that was it. If it was the alternator, I would think it would stay on. ?

One last thing. I don't know if you use your ebrake regularly or not. Your problem could be caused by not using the brake regularly and then one day applying it a little too hard. You only need apply it with enough pressure to secure the car from moving. Obviously light pressure on an even grade adding more as the grade increases. This will keep the shoes/cable in good condition. As with anything, use it or lose it! :cheers:
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Actually, I never use that brake. I only applied it today to keep using it hoping if it was the brake causing it that me using it would help. Strange it (light) came on, because I had never used it. I guess it was sagging down or something. Drove the car several miles today and the light never came back on when driving. Hopefully that was it. If it was the alternator, I would think it would stay on. ?
One last thing. I don't know if you use your ebrake regularly or not. Your problem could be caused by not using the brake regularly and then one day applying it a little too hard. You only need apply it with enough pressure to secure the car from moving. Obviously light pressure on an even grade adding more as the grade increases. This will keep the shoes/cable in good condition. As with anything, use it or lose it! :cheers:

I think you might have dodged a bullet my friend. Start using that brake regularly. As far as the alt goes, if it's dry and you don't have any other warning lights lit up or other electrical issues, then I don't think it's a problem. You're probably losing the p/s fluid through the intake as Thomas suggests. It's also possible for it to leak without hitting the alt. Keep an eye on it, just to make sure.

:cheers:

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Thanks. I will keep a check on it and tell my MOM to use the e-brake regularly. You see, I am giving this car to her as soon as I get hers fixed to use as a daily driver. Then I bought another Mercedes today as my second car and I think she (the Lex) is mad at me for giving her away and then buying a Mercedes! :lol:

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My dim light would come and go, even though the brake fluid level was fine and as far as I could tell, the parking brake was fully released. I am not saying a dim light is a definitive indication of a pending alternator failure. It was in my case when I put the two occurrences together. Most likely you have the original alternator. 200m is pretty good service from that part! I have the complete service record for my car and the alternator was original, 150m. When I was researching alternators at the time someone mentioned that the failure at this many miles is typically the worn out soft metal armature so not feasible to rebuild yourself. Other cars like my Mercedes you can easily replace the brushes with a new voltage regulator.

glenmore

1990 LS400

1991 300CE

2000 C280

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Thanks. We will keep a check on it. Speaking of Mercedes, I am glad that my Mercedes has the alternator away from the PS pump. :) Luckily, the pump does not leak anyway. In fact, no leaks.

My dim light would come and go, even though the brake fluid level was fine and as far as I could tell, the parking brake was fully released. I am not saying a dim light is a definitive indication of a pending alternator failure. It was in my case when I put the two occurrences together. Most likely you have the original alternator. 200m is pretty good service from that part! I have the complete service record for my car and the alternator was original, 150m. When I was researching alternators at the time someone mentioned that the failure at this many miles is typically the worn out soft metal armature so not feasible to rebuild yourself. Other cars like my Mercedes you can easily replace the brushes with a new voltage regulator.

glenmore

1990 LS400

1991 300CE

2000 C280

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  • 3 weeks later...

Well, well, well... the light has been coming back on, again dimly illuminated for the past two weeks. It comes on until its been driven awhile, then it goes off. I am now thinking its not the brake itself and is the alternator.

Strange, one would think that it would be the BATTERY light illuminating dimly if it was the alternator starting to go out, not the brake light. :rolleyes:

I am supposed to give the car to my mom soon as mentioned. I guess when the time comes that I will pay to have it replaced. <_<

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  • 4 weeks later...

Update- the light is staying on more now and its almost at full illumination. Depressing the e-brake only barely makes it brighter. I wonder whats next? More warning lights?

If its going this far bad (alternator), I cannot figure out why the battery light is not the light illuminating. Seems strange that a bad/failing alternator would cause the brake light to illuminate. Crazy cars.

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A quick way to check if your alt is charging properly is to hook up a battery charger after driving the car for at least a half hour on the highway. It will show you on the meter whether it's delivering a high current (battery did not recharge during the drive - meaning the alt is suspect) or just topping the battery off. If the charger tops off the battery and then shuts down (must have an auto shutoff feature when battery is fully charged), then your alt is fine. Of course a multimeter would be better.

If your brake fluid level is ok, and you have no other lights coming on, even dimly, then I would suspect the warning system. Connections/switch/loose bulb/circuit.

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Thanks. Probably another stupid sensor... my "low coolant level" light is already on the fritz. Shows coolant is low when its actually FULL. <_<

If your brake fluid level is ok, and you have no other lights coming on, even dimly, then I would suspect the warning system. Connections/switch/loose bulb/circuit.
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