as long as battery is connected, my parking lights are on and so are my dash lights. Tried replacing the combo switch today with a spare and no luck same problem. Even when combo switch is unplugged entirely, parking lights are still on and so are dash lights. Guessing this is a short or a relay. Everything else seems to be fine. Any thoughts on where to start looking next, basically what would send 12v to both the parking lights an dash lights but nothing else?

 

Do you have a trailer wiring kit? The are known to cause problems. Also, check the wires and grounds in the rear lights.

 

I agree with grounds if the lights are dim (back feeding) and erratic but it seems I worked on an 80 something 2WD and there was a gizmo behind the glove box that had failed.

 

Another thing if this has a alarm or parts of one

I have seen them cause this to happen

Look for any wiring that does not belong or looks out of place

If you pull the tail light fuse see if that turns them off.

Just possible the contacts are fused on the tail light relay

Happy Demon hunting!!

 

So I removed this fuse from the fuse box in the engine bay and all appears to be right with the world again. The parking lights, tail lights and all turn on again using the headlight stork on the steering column and are otherwise off. Not sure why exactly just removal and not replacement of a fuse has resolved this issue. At least I think it's resolved. Any problems with driving without this fuse? I would have thought without this fuse, my parking lights and etc... would not work at all?

 

Now I don`t have a 87 Truck I have a 86 and A 88 here.

The fuse you pulled unless your wiring has really been modified is the Hazard/Horn Fuse!!

The only down side is these not working with the fuse pulled.

Which really makes me think there is a alarm or parts of one in the truck.

Did your Horn ever work??

Did the Hazard lights (4 way flashers) work at all ??

Will either work with the fuse pulled?? They should not but at this point who can say.