14. Bulb Failure Modules on the 1988-1994 XJ6 or xj40 Jaguar
Bulb Failure Modules (BFMs) have a reputation of failure on XJ40s (XJ6), usually it's one of a few simple things.
1: Make sure that every bulb works! The failure module is designed to alert you that a bulb is out, so check this first (easy stuff first).
2: Clean the bulb contacts in the sockets. This is a pain, but this too is a trouble spot. CRC spray electronics cleaner is a good tool to use and it's available everywhere. Use it outside, please, we don't want anyone poisoning themselves.
3: Brass-based bulbs tend to corrode more easily, so don't use them. The safest bet is to get all of your bulbs from Jaguar.
4: Hooking trailer lights to the lighting harness can also cause the failure module to trigger.
5: Open up the modules and look for broken solder contacts. This is usually the problem with the failure module and can usually be rectified easily with careful application of a soldering gun.
6: Once all of these steps have been taken and the failure module still acts up, you are usually stuck with replacing the failure module.
See our Jaguar Parts Store Catalog to order parts.