I have a 94 xjs. Headlights stopped functioning four days ago. High beams work. Parking illumination works. Low beams do not work until car warms up. After 5min, I can switch the headlights off and then switch them on again and they will function from that point until the car cools again. Is this a relay or the headlamp control module? How do I diagnose? Thanks.


Headlamps.

 

I would guess the headlight relay is bad or has a bad connection. Its on the left fenderwell.
Should have a Hella name 1X2 X 3" in size

 

Do you mean the DAC6902 Headlamp controller module DAC6902 ? Is there a way to test before buying. It is no longer made and is pricey when found so I would rather not buy one to sit on the shelf.

This is now my third week with the problem and it is really consistant. The temp of the motor/motor compartment is key to lights being able to illumniate.

On this model, the headlights will not shine at full bright (like problem) when the motor is shut off. Where is that control switch and could this be the issue? (How is this verified?)

Steve

 

If I move the relay module DAC6902, the headlights illuminate to low beam as if relay is functioning properly. I have cleaned the contacts on the module and reseated the connector. This did not help but moving the module seems to. Tapping the module does not help. Moving the wires to the connector does not seem to help. Is it possible that the module requires good ground from the metal clip on the back to function properly? I did not have time to clean and test this morning but am going to try to find some confirmation of this tomorrow evening. (via testing/manual)

If anyone can confirm that the metal clip on the back provides ground...

 

I bought a new dac6902 module from Welsh. ($90) I without checking the diagrams, my testing showed the rear clip does not have ground. I found that a sharp tap of the finger on the module would illuminate the lights. I am going to pull apart the old one and discover rig for future use.