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turbo74pinto

My Dashboard Looks Like A Christmas Tree

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hi. it seems as though my car thinks its christmas. just so you know, i did do some searching and infact fiveofakind also posted a simalar problem. the car is a 92 ls400. ive been driving the car for about 2-3 months now. about 3 weeks ago, i had a few dash lights flicker then go off. a day or so later, they flickered and stayed on for about 5-10 min then went off again. the lights illuminating are red brake, battery, low coolant and low oil. now, after the car is warm they come on and stay on. cold starts when i leave the house, there are no lights on. after i drive roughly 5 minutes, they all come on. when they first come on, they do flicker a little. they also seem to turn off with acceleration and braking for a minute or so. then they just stay on. when the dash light rheostat is not turned all the way clockwise, the lights flicker. but once its switched to full bright there are no problems. i suspected an alternator or battery problem. battery is new as of feb. terminals tight and clean. passes a battery load test. alternator puts out a rough average of 14.1 volts at idle. passes under load and no load. load tests are done with my battery/starter/charging tester from caltron. volt tests just with a plain old dvom. the ps pump was leaking and is replaced. this started about a week before i replaced the pump. today, i drove for a little more time then normal and the yellow trac light came on in the middle of the speedo. it was raining so i punched the gas from a stop. trac was dissabled. shut the car off and restarted, light went off and trac worked fine.

i pulled the wiring diagram from all data and it seems the only wire those 4 original lights have in common is the yellow alternator wire. i havent gotten any farther that that as of now. no time for my own junk it seems. i did not test how many amps this alt is putting out either. i figured id post this and see if anyone else has run into this and what they have done.

thanks

bob

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Yeah, from the little I have researched it sure seems like the alternator can cause weird problems. Now, you checked the DC voltage, but do you have any idea as to any AC ripple on the line? In general, computers dont like AC (like when a leg of the rectifier circuit is toast).

Lastly, any codes that you have been able to pull?

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the batt tester does do a ripple test which it passed. keep in mind, thats with the tester hooked to the battery. i have no clue whats going on b y the alternator. you know, i should have checked codes. i dont think there are or were. when i got back to the shop, i disconnected the battery for a few and hooked it back up to see if the lights would turn back on or not when restarted. they came back on. if i get a few min tomorrow, ill see if there are any codes.

thanks

bob

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You might want to check the trunk hinge wires. Pull the left side trunk hinge cover and take off any electrical tape and check every wire for cracks or splits. Some might even be brken inside the ensulation so make sure and feel all the wires. That is the only soultion I can think of if battery and alternator check out. Is your batter old by any chance. If it is going out I have heard they can cause crazy issues like this.

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turbo,

1992 LS400 - I stopped by Bob Baker Lexus in El Cajon, CA yesterday & discussed with a service technician ( not a service writer - because they dont know s**t ) my 5 lights coming on ( battery indicator, Brake light, low level radiator light, low oil level light, & antilock light ) upon acceleration from a stop.. they will come one, maybe flicker & then would go off as my foot depresses the brake pedal when coming to a stop - odd.

The service technician indicated that it may be alternator related... I discussed with him that a just replaced the battery ( due to a bad cell )& had the alternator rebuilt ( had bad diodes in the rectifier & a bad IC regulator )about a month ago...

He said make sure of your connections on the back of the alternator....may have worked loose, check the plug on back of alternator that plugs into the IC regulator....

I mention the trunk lid wiring harness & the technician indicated that would cause a different set of problems but he did not elaborate...so he said to focus on battery & alternator....

I will check to see if I have a power steering leak that just started. When I installed the battery & alternator a month ago, I did not notice any leakage from the power steering pump at all. I will recheck but I dont think this is the case.

I know my battery connections are tight with no corrosion.

Keep me posted on what you find out....& I will do the same.....strange these lights are intermittently coming on....hard to troubleshoot......I hate electrical issues...

5ofakind

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turbo74pinto,

Any update on your problem ? Mine are still flickering. I will check this weekend for P/S pump leak that may be just starting. I would hate to ruin a rebuilt alternator I just installed about a month ago.

5ofakind

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turbo74pinto,

Any update on your problem ? Mine are still flickering. I will check this weekend for P/S pump leak that may be just starting. I would hate to ruin a rebuilt alternator I just installed about a month ago.

5ofakind

You might try disconnecting your alt and driving around (keep it very local...maybe just neighborhood) and see if the lights flicker. Of course the alt light will be on but should not be flicking. With a good, fully charged battery, you should be able to distinguish between alt. and other circuitry. In other words, if the flickering still occurs with no alt., then you can be fairly sure it is not the culprit. The battery or loose wiring would then be suspect.

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a little more info. i had about 30 min to look at it a little today before i went out and bought yet annother car. my house and shop are looking like a used car lot. anyhow, when i got back to the shop from work i started it up and let it run. as ive said before, i have no problems with it when its cold. so as the cars idling i opened the trunk and looked at that harness. its all original and no cracks or broken wires that i could see. i waited for the light to turn on. it flickered a couple times then stayed off again. i opened the hood and got my dvom out to test batt voltage. reved it a few times and they came on. i wiggled and moved the wires around on that trunk harness...no change. i went back to the batter to test voltage. it was a little higher, around 14.9ish. i goosed the gas to roughly 4500 and the headlights got brighter and never dimmed. the idiot lights on the dash were flickering bright to dim erraticly. checked the battery voltage, 15.6ish. goosed the engine about the same a few more times, lights dimmed and back to 13.8ish volts. goosed again and had spikes up to 17.6ish volts. all these spikes and readings is what i was getting at an idle, not during the revs. i did not check the connections at the back of the alt. i wanted to but there was something about my hand being next to that hot header. needless to say, i didnt "f" with it. im pretty confident that this is an alternator/regulator issue with mine. while the idiot lights were on i would rev it quick to 4500-5000 (tach doesnt work so i dont know exactly) and they would go off. rev it again after a few seconds they would go on. priced the alt at my parts distributor and its only 107 before tax. ill have it monday although i dont know when ill put it in. sometime next week. in the mean time, ill check those connections on the back of the alt and let you know what i see.

bob

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I am going to be *BLEEP*ed off if I find out that the culprit is the alternator also. I just had it rebuilt about a month ago by a reputable shop....

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i think the problem is solved. i put an alt in today and it ran for 2 hours. no lights. all light flickering is gone also. ill let you know after a few days how it acts.

bob

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turbo,

I removed my alternator this weekend & took it back to the auto electric shop to have it re-tested. They bench tested the alternator. The rotor was bad. At higher RPM's, the windings in the rotor would open up. They replaced the rotor & I will re-assemble this weekend.. Now that the alternator is out of the car, I can clearly see underneath the power steering pump. There are no leaks or drips coming from the p/s pump. That's good.

Hope this helps your situation.

5ofakind

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the alt has been in now for a hand full of days and roughly 150 miles put on it with no lights!! looks like that was the problem. also, i think the car is sold, lol. i let someone use it while i fixed their car. i called them yesterday to tell them their car was ready and they asked how much for the lexus. so, i think its going to another owner from here. fine by me, more hot rod money!!

thanks again for the help!

bob

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