I'm dealing with a 1985 S10 Blazer owned by my late brother, and the car was partially disassembled when he died, including the headlights, the parts of which I found in cardboard boxes in three difference places. Adjustment hardware was missing or broken, one spring was missing, and the shells were very rusty. When that was all fixed, I found that the driver side contacts wouldn't keep good contact, being old, oxidized, and having lost spring grip. The connector housing was partially melted on one terminal. The passenger side connector had already been replaced.

I've figured out that the original stock connectors were a "Series 59," and these are a lot better for higher currents that standard push-on connectors, which don't have great contact integrity. (I work in audio electronics, and quick-connect terminals cause a lot of problems.) A lot of replacement products I saw online use cheap quick-connect terminals. The originals have a much larger contact area, which is what you need for headlights. In other places, they used Series 56 terminals, which are 1/4" wide.

What I don't have access to is the nice crimping tools GM seems to have had. Not sure if anyone here would know what those would have been called.

My late brother had put Hella H4 headlights on the car, standard wattage, but much nicer than standard sealed beams.

In general, on a 34 year-old car, I'm finding that you have to look very carefully at all the electrical connections. I call it "dental work." You just have to get in there with your tools and clean away the oxidation -- or replace if it's too bad.

 

[QUOTE=What I don't have access to is the nice crimping tools GM seems to have had. Not sure if anyone here would know what those would have been called. [/QUOTE]

Sorry I solder and heat shrink all splices ....