My battery,oil,radiator and brake light come on while car is running when drivin it goes off stop at red light it come on but when mash gas thay go off then when going to stop again thay come on

Asked by Jan 24, 2015 at 06:54 AM about the 1990 Lexus LS 400 RWD

Question type: Maintenance & Repair

5 Answers


It seems like all your belt-driven accessories come on when engine is at idle. You have a serpentine belt with tensioner, open the hood and inspect the belt and tensioner and see if it is tight. If there is too much play in it the tensioner may be bad. Your oil light is not related to the belt, you may have low oil pressure, so check your oil level, if it's okay you may have a dirty/clogged filer, or even a bad oil pump/clogged filter screen. Check your brake fluid too, if okay then the light may pertain to the operation of the ABS. It's not often all warning light come on with a valid reason but then again you are driving a 25-yr old car with who knows how many miles... the problem may even lie in the dashboard warning lights. Go through each system and make sure all fluids are topped off and drive belt is good. Take it to an auto parts store and have the alternator checked (it's free). Hope this helps.


KenF pretty well has summed up what every cyber space mechanic would advice you. The only thing I can add to it is for you to ask yourself how long ago did you get your car serviced. And, how often do you service your car? Do you make a point of doing regular maintenance? Lexus makes very reliable cars. They don't give out full-blown warnings the way you have described. This is a very extraordinary case. Perhaps yours is an extraordinary Lexus. Cars behave fairly similar to human beings. Even a very strong and healthy person should not ignore regular maintenance.


I have a 1991 Lexus LS400 and im having the same problem with all the lights coming and going off. However mine acts like its hesitating when you press the gas if it has low power like the gas line has been shut off. Sometimes it cuts off and starts right back up. Other times you have 2 wait like 30 minutes before starts. Other times it runs great. Also my temperature grudge is on high as if the car is over heating I do keep the maintenance up on it recently had a tune up spark plugs spark plug wires rotor buttons distributor caps PCV valve oil change fuel filter air filter timing belt water pump crank sensor coolant temperature sensor a camshaft sensor coolant flushed thermostat and radiator cap all done to my car. Still can not figure out what's the problem. Alternator and battery replaced 2years ago and still check out fine

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I pulled out the telephone fuse, and lexus ride system fuse as I don't have air suspension nor the telephone, and the next day all warning lights came on at idle. once the car warmed up the lights did not come on. also the a wire harness behind dash is in poor condition. 1990 ls400 277,000 miles


I had a 91 ls400 that would cut out and not start. it was a bad or loose cam sensor. If I wiggled the wire on the front drivers side of the engine that led to the sensor, it would start right up. Also, the LS400's had faulty capacitors in their computers, they would leak and cause all sorts of strange problems. the computer is located behind the glove box. T/he capacitors run around $10 for the complete set and are easy to replace IF you can solder. another common problem with the LS400's is the wires break in the trunk near the drivers side trunk hinge. This also will cause strange electrical and radio issues.

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