QuestionQUESTION: My 1999 RAV4 cooling fans will intermittently start and run with ignition off. Also, when engine is running both fans will start and stop with A/C off. I believe both fans are running at high speed, but I don't know that for sure. The ignition switch was replaced, but problem still exists.
ANSWER: The fans will start and stop running when the A/C is off. There are sensors in the radiator that sends a signal to the computer so the fans will run when the temperature gets to warm. Simple test can be run
to test the sensors and relays, this must be done by an experienced Toyota technician.
---------- FOLLOW-UP ----------
QUESTION: Thanks for your reply. As a follow up, please note the fans will start sometimes several days after the car is shut off and keys removed. Therefore I don't believe temperature is is part of the problem. On one occasion after the fans started, I removed the ECU 1G fuse and the fans stopped. Also, several times only the A/C condensor fan started. I am suspecting the IG1 relay, but cannot determine its location. (I have found the IG2 relay, but not the IG1 relay.) The other symptom I noticed is when the fans are running in the ignition off condition, the oil pressure and seat belt indicators are very dimly lit. It's as if minimal voltage is being applied.
AnswerDavid,
Was the vehicle in an accident?
Pull the cover off the relays and fuse boxes under the hood, they are marked. This could be a problem with the alternator, I've seen some crazy things happen with a goofy charging system. A expert Toyota technician can pinpoint the problem.
Good luck, let me know what you find out.
Tim
