Hi everybody -
I'm a newbie who just bought a 2001 XJ8 VDP w/ 75K miles. A wonderful car on the highway, very comfortable. I got it for cheap because it has a few, er, issues. The first is:
The interior lights, the vanity lights, the map lights, the globe box light, the outside mirrors, the tilt column and maybe a few other things DON'T WORK. Fuse #7 in the left hand heelboard, 15A, which supplies B+ to the Body Control Module for "solenoids, lamps and motors" was blown. I pulled the blown fuse, and a new one blew as soon as I inserted it in the fuse box.
So my first thought is that either the body control module is blown, OR, one of the circuits it feeds is shorted to ground but the BCM is all right. I don't think the BCM can be completely blown, as other functionality that goes through the BCM and has other B+ feeds, still works.
I am thinking of cutting the wire from pin 101 BCM (which feeds the map, courtesy and visor lights) and then trying another fuse. If that doesn't work, I may get another (used) BCM.
Anyone have any thoughts on this? Thx.

 

Remove BOTH sunvisors and look at the wires that are probably shorted to earth with the mount screws!! That is the most common fault (ask me how I know???) Put a new fuse in and see if the fault reoccurs. Make sure the wires are tucked out of the way when reinstalling the visors!!

bob gauff

 

Boomer, I would try a few other things first before cutting wires. I would first access the body control module and unplug it. Then, install a new fuse into the #7 location. If the fuse blows this time, then you know you have a problem with the brown/white wire that runs between the #7 fuse and the BPM. If the fuse does not blow, then what I would do is remove the pins to the plug for the BPM for the various lights (specifically pin #101-red/white wire, pin #57-green/red wire, pin #74-red/white wire, and Pins #90/40/93/99/100/91/66/78/52 (all as a group as these feed the steering control motors)). What this is doing is removing a lot of the ancillary stuff that the body control module controls. Then what you do is put the plug back in with the wires removed (don't forget to label each of these wires where they go so they can be placed back where they need to be). If the fuse blows now, then you know you have a bad module. If the fuse doesn't blow, install the wires one at a time (except for the ones for the steering column motors). Checking the fuse between each install. If the fuse blows, then you know the bad circuit. From there, I can lead you towards where the problem can be.

Just for reference, the BPM only sends a signal to the left/right door processors to control the mirrors, it doesn't control the mirrors directly.

For reference, this is what the various pins are doing:

Pin 101 - map lights, garage door opener circuitry, glove box light, left/right vanity lights, and trunk lamps
Pin 57 - courtesy lights in the roof console
Pin 74 - left/right hand e-post courtesy/reading lights

Something else you may want to do is each of these lights do a detailed inspection of. In the past, I have seen one of these light sockets short to the body of the car via a screw or something like that, leading to what you are seeing. It may not always be evident what is going on and can be a PITA to find.

Let me know. We will get you fixed up as soon as we can. It sounds like you atleast know a little bit about electricity. If you can give me a quick run down of what your abilities are, that can help me decide how detailed I need to get with the instructions. If you need to know how to remove the pins, let me know. IT is pretty easy to remove pins, just takes a really small screw driver.

 

Hey everyone,
I've had the same problem for several months. Drove me crazy. Changed the BPM, changes the tilt-extend switch, many, many fuses to no avail.
Just pulled the Pass enger sun visor and there were two wires burned to a crisp and still arcing with a new fuse on No. 7, left heelboard.
Removed the sun visor catch and the overhead console and dropped the front of the headliner, traced the wires to clean part and snipped them, taped ends.
No light in Pax sunvisor but everything else works.

Thanks, motorman, YOU DA MAN!

 

Well, that is interesting. I take it that the problem is with the wires that go to the visor mirrors short out ? Never heard this one before. I hope Boomer gets back and lets us know if this was his problem. Thanks motorcarman.

 

It's not that the visor light wires 'short-out' it is that the power wires to the visor are in close proximity to the mount screws and when the screws are inserted and fastened, they get into the power wires to the visor lighting. After years and years of finding the same thing over and over you just know what to look for before wasting alot of time with modules and fuses. Sometimes it's easy and sometimes it's almost impossible to find the fault!!!!!!!!!!!
Often the hardest faults to find are with the modules themselves because they are expensive and some need to be configured to the car. Then you find out that the new module makes no difference. (I HATE THAT!!!!!!!!)

(Sometimes I miss points and condensers, switches and wires!!!)

bob gauff