91LexusLS400 Posted January 26, 2009 Share Posted January 26, 2009 91 LS400 The battery, brake, coolant & oil lights of course come on when starting the car then go off normally. But lately I'll be driving and all 4 come on at the same time. If the cruise is engaged, it kicks it out of cruise mode but the cruise lite is still on in the dash. I don't have to be in cruise mode for the lights to come on. Sometimes the lights are constant, sometimes they flash rapidly, sometimes they flash not so rapidly. When I step on the gas they go out most of the time. If I step on the brake while they are flashing, they go to a constant...no flash. The car runs the same, isn't getting hot or anything...runs perfect. Theories? Quote Link to comment Share on other sites More sharing options...
AzHotLS Posted January 26, 2009 Share Posted January 26, 2009 Broken wire in the left trunk hinge cable harness. Many threads on the subject. Quote Link to comment Share on other sites More sharing options...
BillyShaft Posted January 26, 2009 Share Posted January 26, 2009 Broken wire in the left trunk hinge cable harness. Many threads on the subject. Someone pointed out yesterday that this problem brings more people to this site than any other issue. On the up-side it is easy to fix once you know where to look! :D Quote Link to comment Share on other sites More sharing options...
TA in KC Posted January 27, 2009 Share Posted January 27, 2009 I doubt this is a problem with the trunk wire harness. I think it is much more likely the alternator beginning to fail, probably due to a power steering leak. I and many others on this board have had the exact same symptoms before a failure. Until you know what the problem is, do not drive the car on busy streets or though busy intersections. A failing alternator will frequently cause the car to shut off randomly and lose all power steering, brakes, etc. It could lead to an accident. Quote Link to comment Share on other sites More sharing options...
eatingupblacktop Posted January 27, 2009 Share Posted January 27, 2009 Have the alt load tested before going into traffic as thomas rightly suggests. Quote Link to comment Share on other sites More sharing options...
91LexusLS400 Posted January 27, 2009 Author Share Posted January 27, 2009 I've fixed the trunk wiring within the past year. My power steering pump is about 1.5 years old, but I'll take a look to see if it's leaking. Quote Link to comment Share on other sites More sharing options...
glenmore Posted January 27, 2009 Share Posted January 27, 2009 P/S may or may not be leaking to knock out your alternator. Could just be a worn out alternator if you are 125k+ miles. glenmore 1990 LS400 1991 300CE 2000 C280 Quote Link to comment Share on other sites More sharing options...
91LexusLS400 Posted January 27, 2009 Author Share Posted January 27, 2009 P/S may or may not be leaking to knock out your alternator. Could just be a worn out alternator if you are 125k+ miles.The alternator was changed back in late 2005...I'll just have to have it checked. It's been about 75K miles since it was changed. Just rolled 358,000 last weekend. glenmore 1990 LS400 1991 300CE 2000 C280 Quote Link to comment Share on other sites More sharing options...
Bali26 Posted January 28, 2009 Share Posted January 28, 2009 Hi, I'm having the exact same problem with my car. The same 5 lights. Same behaviour. Come on sometimes when driving. Go out at stoplights sometimes. Its not the alternator as I had it checked, also its new. Problem is when I went to the mechanic the lights were out. They mostly come on when driving. Checked the trunk hinge too. Nothing wrong there, all wires are intact. For alternator: Trac off and check engine should come on too. For trunk hinge: Problem should occur on braking only. This is something entirely else. Maybe a bad ground somewhere. I cleaned the battery posts already. Quote Link to comment Share on other sites More sharing options...
BillyShaft Posted January 28, 2009 Share Posted January 28, 2009 I was under the impression that the "trunk problem" could cause any number of crazy unrelated electrical issues...not just brake related. Am I wrong again? Quote Link to comment Share on other sites More sharing options...
Bali26 Posted January 28, 2009 Share Posted January 28, 2009 I think trunk hinge issues come up even when not braking, but increase during braking. However in this case there is no other symptom, just the 5 lights coming on without any reason. Quote Link to comment Share on other sites More sharing options...
91LexusLS400 Posted January 28, 2009 Author Share Posted January 28, 2009 5 lights? I only get 4. I do not have traction control or air ride. Thank God. Now that you mention the ground problem, my battery cables/terminals are in need of replacing. I had to jump the car off the other day (door light switch stuck and left the lights on) and had to wiggle the connections on the battery for it to get good contact. I'll try here, then see what happens. The battery cables don't look like you can get them at autozone...what are my options? Quote Link to comment Share on other sites More sharing options...
BillyShaft Posted January 28, 2009 Share Posted January 28, 2009 5 lights? I only get 4. I do not have traction control or air ride. Thank God.Now that you mention the ground problem, my battery cables/terminals are in need of replacing. I had to jump the car off the other day (door light switch stuck and left the lights on) and had to wiggle the connections on the battery for it to get good contact. I'll try here, then see what happens. The battery cables don't look like you can get them at autozone...what are my options? They shouldnt be erroded to the point of needing replacement, probably just a good cleaning. Pick up one of these lil tools or one of its' similar cousins and give the terminals what-for. Reconnect the battery terminals and you should be good to go. Quote Link to comment Share on other sites More sharing options...
AzHotLS Posted January 28, 2009 Share Posted January 28, 2009 I had to jump the car off the other day (door light switch stuck and left the lights on) and had to wiggle the connections on the battery for it to get good contact. So your problem started after this? Try removing the negative battery cable for 10-minutes (or however long it's supposed to take) to reset the ECU. Quote Link to comment Share on other sites More sharing options...
91LexusLS400 Posted January 28, 2009 Author Share Posted January 28, 2009 5 lights? I only get 4. I do not have traction control or air ride. Thank God.Now that you mention the ground problem, my battery cables/terminals are in need of replacing. I had to jump the car off the other day (door light switch stuck and left the lights on) and had to wiggle the connections on the battery for it to get good contact. I'll try here, then see what happens. The battery cables don't look like you can get them at autozone...what are my options? They shouldnt be erroded to the point of needing replacement, probably just a good cleaning. Pick up one of these lil tools or one of its' similar cousins and give the terminals what-for. Reconnect the battery terminals and you should be good to go. They're not corroded...the ability to tighten the terminals is gone. The bolt/nut is as tight as you can go, but not 100% tight around the post. The problem didn't start after the dead battery part, but I'll be resetting the ECM when I get to the new battery cable ends. Quote Link to comment Share on other sites More sharing options...
Bali26 Posted January 28, 2009 Share Posted January 28, 2009 5 lights? I only get 4. I do not have traction control or air ride. Thank God.Now that you mention the ground problem, my battery cables/terminals are in need of replacing. I had to jump the car off the other day (door light switch stuck and left the lights on) and had to wiggle the connections on the battery for it to get good contact. I'll try here, then see what happens. The battery cables don't look like you can get them at autozone...what are my options? Yes 5. Batt, Brake, Oil, Coolant, TailLight check. I've already replace and cleaned my terminals and contacts. Checked alternator voltage, trunk hinge too. The problem is something else. Let me know if you fix yours. Quote Link to comment Share on other sites More sharing options...
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