Ok guys, with my fuel injector issue resolved, I decided to start tackling the other issues with the car (wiper non functional, damaged wiring on RH headlamp module, RH headlamp filled with water, horns stuck on if I put the fuse in...) So first I decided to tackle the headlamp and wiring damage. Now, I should state that before I did any work, ALL the lights worked, even with the headlamp full of water and the module wiring severely chewed up. I installed the new right headlight, and I put in a RH Headlamp Module I got from a 1994 XJ6 in a salvage yard. The part numbers were different on the modules, and I noticed that the original module had a diode pack that plugged in, whereas the 94 did not. The original one in my car was part #DBC12033, and the 94 was LMD2240DA. After swapping the module and installing the new light, I started the car, flipped the lights on, I can see the headlights both working, check the turn signal and the LEFT one is blinking fast. My LEFT front bumper light, side light, and turn signal are all out. All the lights on the RIGHT side, where I put the 94 module, are working perfectly. I tried swapping back to the 93 module with the damaged wiring, but still the left front bumper/side lights are out. Any body have an idea? Did I mess something up with the 94 module?

 

Hi Michael,

If I recall correctly, the left front BFM is powered by completely different fuses than the right BFM, so double-check the wiring at your left BFM and bulbs and check the fuses for that side.

Cheers,

Don

 

Don, I figured it would be better to ask here instead of start a new thread. I can't seem to find an answer as to what it is or even finding in the wiring schematics... What is the purpose of the plug in diode pack on the headlamp modules?

 

If you mean the diodes that plug in to the BFM harness, they're not shown on the schematic, but my guess is that they are there to reduce radio frequency/electromagnetic interference (RFI/EMI) that could cause interference in radio reception. A diode & capacitor are across the fuel pump leads for this reason.

If there is some other diode pack, perhaps they could be part of the bulb filament resistance sensing circuits that tell the module if a bulb filament has opened or a bulb is missing. The relays in the BFM are protected with a resistor and diode in parallel with the coils.

Hopefully another member will know more about those diodes.

Cheers,

Don

 

Don, yes that's the Diode I was referring to. The 94 BFM I put in on the right hand side doesn't have the diode pack. The diode pack plugs inline in the Brown w/ Green tracer wire, which looks to be power to the turn/marker light.