I have 87 truck xtra EU spec, the PO did some electrical modifications I would like to undo.

Some context: I was told fines for driving cars with lights off during daytime are expensive in the place where I got the truck, so owners modify old vehicles to keep them always on (sort of). I would like to change that to stock, but I do not have the FSM for this model, so I do not know where to start.

The table below shows the problem, what the lights do based on the key position and the light control position in the combo switch:




So what I would like to do if turn all lights off when the light control position in the combo switch is OFF.

Some guidance please.
Thank you!

 

So, it appears that somebody fed the signal from "On" key position to the headlight relay, or add another relay in parallel into original. We have no insight into your car's wiring, what you should do is remove the plastics around the steering column and look for any non-factory wire bridging those two circuits. If not around the steering column, then possibly in the drivers kick panel or under the hood. I can send you FSM, but it would be little help as you're looking for a DIY solution someone did.

 

I am going to try that.
Thank you Jake.Werecat!

 

IIRC, Headlight circuits are similar from 1984 to 1988.
Headlight relay should be is in fuse block in engine compartment. Pls check for anything not stock there and underneath (where wires are).
Unplug the headlight relay. Do headlights still come on even with dimmer-combo-stalk switch off?
With combo-dimmer-stalk switch OFF, when do the headlights com one? Accessory on? Ignition on? When that happens does the headlight relay click? If it does, then modification was upstream. If it does not click, then modification was done down stream-most likely ad added relay sending power to the fuses.
Do ONLY the headlights come on (like daytime running lights), or do tails come on as well?

 

Thank you Ray!
I am going to check that, I expect to work in the truck this weekend.

 

How did it went? Mission successful Mr. McFly?

 

Call me Marty.

I haven't solved it yet. New job, "new to us" house that needs a lot of attention, and I do not have place to work with the trucks at the moment. They are in the in-law's house until next Spring, but we drive them once a month.

I am in the search for the missing parts, the only thing I can do these days. The OEM radio was one of them, I got one last week.

I will update this thread.