My 2001 Limited has developed a bit of an issue with the headlights. Occasionally when I turn them on, they flicker on and off - almost like they aren't getting enough power to successfully engage, then after a few attempts, they come on fine an stay on with no further problems. Well, last night, the wouldn't come on at all... the dash lights, running lights, and blinkers all worked fine, but not head lights or fog lights. I immediately checked the fuses under the hood, but they were fine. I cycled the switches numerous times, fiddled with the head light bulb connections, banged, cursed and gave up.

Just when I was resigned to limp blindly to a gas station and leave it until morning, the lights came on (as soon as I started moving...) and worked fine again. When I got it home, they continued to work fine as I tried to duplicate the problem. It seems to occur only when the vehicle is cold.

The dealer is clueless and wants to "diagnosis it" at $100 bucks an hour.... before I do that, any ideas out there? Is there a relay or power converter somewhere in the system I should check? Neither switch (fog or main lights) appears to be defective.....

Any help would be appreciated.

 

It sound like a dirty contact in a relay or a partially broken wire. I would initially lean toward a relay issue. When a contact get burned or gets dirty it take more power to close the connection. I would check the relay system and see if you have a faulty relay. If you have a VOM you can diagnose this problem relatively quickly.

John

 

If it is a problem mainly when it's cold, it is probably a corroded contact that is barely getting enough current to cause the relay to turn the lights on. The corrosion causes high resistance and in order for the 12V to get through for the relay, it will require a higher current draw. The high current draw will heat up the circuit/wires/relay and will fix the problem temporarily until it's allowed to cool again.

Here is the way it works, the switch on blinker shaft powers a relay which switches the power on to the head lights.

You need to figure out where the power relay is for the head lights. There should also be two different fuses. One for the interior switch to the relay (12V but low current) and a larger one for the relay to the lights (12V but high current). The relay itself might be going bad which is only a $26 part.

http://www.trademotion.com/partlocat...01&catalogid=1

Good luck finding a schematic for the wiring. The cheapest way is to trace the wires from the head lamps back to where the relay is.
~Steve