Darwin503

Ok, I found an after market wire spliced into some other wires in the trunk. It led to a switch under the steering column (kill switch?). The switch did nothing so I removed the wire. The correct amp fuse now works.

However, I'm still getting a tail lamp warning light. Any thought?

Mrmerlin

do your rear side marker lamps work?
are the same bulbs used on all of the side markers?
do your tag lamps work?
did you remove the tag lamps from the PU cover to inspect the wires?
do your front side marker lamps work?
did you clean the side marker connectors in the hatch floor area.?
Did you clean the grounds behind the RR interior liner in the hatch area?

Darwin503

I will do that next weekend. For now, I'm glad I got the tail lights working.

Thanks for everyone's help.

Alan

The only monitored lights are brake lights (one circuit) and rear markers & rear side markers combined (the other circuit). It's always comparing right to left and min/max values.

Just fix the rear/side markers - you will have a warning until you do.

Alan

Alan

Perhaps I wasn't clear - NEVER DO THIS AGAIN!!

You can easily destroy your wiring looms by doing this - even just for an instant. A bigger fuse will never tell you anything interesting you can't find out better a different way. Replacing a loom in a 928 is very expensive and extremely frustrating & time consuming ... you will for sure regret anything you ever do to cause that...

You can get good advice here on lots of things - but you have to listen...

Alan

Darwin503

Thanks for your help.

The lights are all on at this point. Based on everyone's feedback, it seems like the warning could be caused by different bulbs or dirty connections?

dr bob

The system is EXTREMELY sensitive to differing current draws from the bulbs vs. original spec. Many have discovered that parts-store replacements vary enough to give the warning even though the bulbs are lit up fine.

Besides getting the CORRECT, MATCHING BULBS for the tail lights and the markers, corroded connectors and sockets will cause enough voltage/current drop to trigger a dash warning.

The corner markers require removal of some fender liners and splash shields for full access, and that usually means the car is on stands or lift with the wheels removed. The marker lamp assemblies are held in by a couple fasteners each, and if possible it's easier to remove the whole lamp for service rather than trying to work on them in place. You'll want t clean any dirt and corrosion from the sockets and bulbs. Since bulbs are cheap you may decide to replace them all now and not worry again for a long time. A soft wire pipe-cleaning brush works well for cleaning the barrels of the sockets. The actual contacts take a little more finesse, and can be replaced if needed with parts from a lamp supply store. Otherwise Deoxit per Stan's recommendation. I often smear the socket and connections with Vaseline or silicone graese for water protection after the bulb is in place, and make sure the rubber boot is secure.

Bulb holders in the tail lights can be replaced if needed with aftermarket parts intended for Ford minivans. A little searching here will get you the right part numbers. They take a little razor-knife trimming to get the latches to fit perfectly, but you get a better water seal along with all new metal and contact parts.

James Bailey

the fuse is designed to be the weakest link in a circuit. When overloaded it heats up melts and interrupts the circuit. When you put in bigger fuses (higher amps ) you may have made the wires in the harness the weakest link so they heat up, melt the insulation and short circuit to each other.
That leads to HUGE problems including nasty electrical fires....or needing to rewire the car !!