My brothers 2000 Cav has an odd issue with the driver side headlight. The daylight running light will come on, but the headlight will not. When you put the car in gear the DRL relay ticks about 15 times and the light on the dash for headlights also flickers on and off. The bright will not come on either, just the DRL on all the time.

There is no problem with the passenger headlight.

We have checked all the fuses, changed the DRL relay, changed both headlight bulbs and tried to check the wires. Is there any area in the wiring that is prone to problems we could look at again?

Check the wiring harness for the lights in the engine bay itself. In my '00 the harness had rested for 5 years on th transaxle housing and melted, allowing water to get in and shorted out the headlights. My brother helped me to get the wiring harness off and reattached each wire to itself and now the lights work fine.

95% of the time all headlight issues on this cars are linked to a broken or corroded wire within the headlight harness.

95% of the time all headlight issues on this cars are linked to a broken or corroded wire within the headlight harness.
:bigthumb: That's exactly what I was referring to. It's a poor "design" that is prone to failure. Take a look closer at the wiring harness on the underside and see if there is any melting. If so, that's where your problem probably stems from.