Still working on a friend’s 1988 XJ6 and I have a “bulb failure” indication on the dash and the right rear turnsignal light is not flashing as expected. The left turnsignal (both front and rear) and the front right turnsignal indicator all function fine but the right rear one only flashes once in a while either with the hazard switch or activating it via the actual turnsignal switch. I have replaced the bulbs in an effort to solve this but no luck so far. Any suggestions?
First off exchange the bulb fail modules side to side to see if the fault travels, if it does then I would open up the offending BFM and check for dry solder joints and clean the relay contacts, you can identify which relay by manually closing the contacts to see which light is connected to which relay.
Hello Steven - if changing sides with the Bulb Failure Module, as Robin suggested, gives the indication that the fault is still at the right rear, then check the solder contact, at the end of the wires that are within the bulb socket, for a good connection - I have found this to be a problem when having the light perform as you have described - Tex Terry, II - 1991 XJS V12 Classic Coupe, 1986 XJS V12 Coupe - sent 9/17/2020 2248hrs.
I had a similar issue with the left side brake light of my 92 VDP. Upon close inspection I observed corrosion in the bulb socket. After a thorough cleaning the bulb behaved as it should.
I did swap the bulb failure modules this evening and the failure followed the module rather than staying on the original side. So my next job is to open up that troublesome module to look for bad solder joints.
BTW, I did this with the overvoltage protection relay and by reflowing three or four solder joints I was able to make the relay actually work and now the ABS warning no longer displays on the dash after the engine is started.