1989 90 lighting wiring troubles

[NPT90]

An update to this. I confirmed both lighting fuses are good and have 12V on both ends of each fuse. From there I went right to each individual lamp and can confirm that problems "seem" to be localized to each lamp, at least in the front. I found corroded bulb sockets etc and could make them work intermittently with random wiggling of fresh bulbs. So, new lamps on order.

Secondarily to that though, the rear lamps seem a bit more f*cked which I think may relate to some trailing wiring, which appears to have been installed by an ape. Will work through that as time allows.

FWIW My incandescent housings were grounding to the body which caused intermittent issues.

Agree with the LED argument, as always I recommend grounding bus bars at the lights but thats just me.

Defenders NW $65

I have worked through dozens of intermittent and lighting issues and I almost always come back to corroded bullet connectors or unions. Once you eliminate grounding points and connectors as failure points its amazing how easy these problems are to diagnose.

I attached some examples of installs I have done over the years. I usually run a redundant ground outside the main loom (especially if its older) just to eliminate it from the equation. I still run the loom ground to the terminal bars but I remove all the bullet BS in the lamp areas.

Hope this helps

 

[acheck]

When I first saw this yesterday @NPT90 I thought it was a clumsy solution.

But after thinking about it overnight I rather like it especially for the rear lights where there is open space in each rear lighting "box" for the terminal block. I don't quite know where the best location would be for each front wing, where the block would be protected, yet easily accessible, and look tidy. Will give further thought.

 

[NPT90]

Keep in mind these photos are of installs in progress vs final installs.

For the front lights I simply put the bus bars inside the wings near the radiator supports. pictures are hard to see.

Effectively you could just use the existing ground wires in the loom. I added the extra ground wires to eliminate the clumsy ground unions on the factory harness.

Really I wired it like a boat, which has no frame ground to rely on.

 

[Uncle Douglas]

When I first saw this yesterday @NPT90 I thought it was a clumsy solution.

But after thinking about it overnight I rather like it especially for the rear lights where there is open space in each rear lighting "box" for the terminal block. I don't quite know where the best location would be for each front wing, where the block would be protected, yet easily accessible, and look tidy. Will give further thought.

What we have been doing for a long time is get rid of the bullet connectors on the front corners and use a single stainless bolt through the galv inner fender. The bolt is a good 1/2 inch longer than needed, creating a ground stud. I use a nylock nut, then a stainless washer, ring connectors on ea lamp ground as well as the main harness ground all onto the exposed stud, then a clamping stainless flat and second nut. Smaller, cleaner,simpler than a buss bar, and way easier to acess in the future. Buss bars up front seemingly would require flare removal to get to in the future. Same effect, and gets rid of the 6 way Leyland bullet connectors. Buss bars are great for the rear, since its inside the truck with great access.

 

[NPT90]

Buss bars up front seemingly would require flare removal to get to in the future. Same effect, and gets rid of the 6 way Leyland bullet connectors. Buss bars are great for the rear, since its inside the truck with great access.

Actually I just added them when I replaced the headlight cans and mounts, access was simple through the headlamp hole and once installed I was able to add additional grounds (like for the headlamp relay) from a bucket over the wing. I ended up going with the bus bars because I couldn't bring myself to scrape the galv off the frame to properly ground to it. The truck had the stainless bolts you describe but they weren't strong grounds to I just eliminated the weak point.

Lots of ways to skin a cat, as always, your experience may vary.