I need some help. The right rear stop/directional indicator bulbs have stopped working in my 1988 Vanden Plas. The bulbs are good. I've checked the fuse and it is good, but I changed it anyway. What else should I check? Also, the reverse and tail lamp bulbs work.

 

I would check the bulb sockets for dirt or corrosion also use a voltage tester to check for power at the sockets. I think the 88s had lamp controllers in behind the bulbs too... maybe you need a reflow of the circuit board?

 

Sockets were not dirty or corroded, but I cleaned them anyway.
It's the weirdest thing. With the ignition off both right side stop bulbs don't work. Turn the ignition on and one bulb comes on then 30 seconds later the other one comes on???? I've done this a few times, and every time it does the same thing.

 

Maybe your electricity is too thick. (Rimshot!) It sounds to me like a problem in the circuit board behind those lamps. I havent any experience in diagnosing these but maybe its a loose connection in there that is almost connecting till it heats up then its good? Think turn flasher....
Its been recommended many times in many places here and I doubted it myself at first, but just using a soldering iron to reflow of the circuit board connections might fix you up.

 

I will check the circuit board and re-solder. I will post an update when resolved.

 

The problem is the Bulb Failure Module. Through some troubleshooting I found that the stop bulbs work only when the engine is running, but do not flash when the directional indicator or hazard is turned on. When I tap on the BFM the bulbs flash for a moment and then stop. This confirmed to me that the BFM is bad. I have ordered one from ebay. I will post an update if this turns out not to be the problem, but I am pretty sure it is.

 

I believe you can reflow the solder joints in the BFM to get it running again

Larry

 

Yes I would have done that, but the cost of $53.00 for the module on eBay wasn’t worth it.