The Stovebolt Site Forums The Shop Area The Electrical Bay Aftermarket Headlight switch issues

1959 1/2 ton
So I seem to be having some chronic issues with the last two aftermarket headlight switches I have bought. The first one smoked it's dimmer reotstat. The second one worked for a while and now the instruments don't light up. I checked to see if there is voltage at the switch where the grey instrument light wire hooks up to and there is none. It's a brand new wiring harness. Bad run of aftermarket switches??

Sounds like maybe a short in your dash lights. Try connecting them to a fused hot wire and see what happens.

I'd recommend buying a good used switch. I haven't looked for one for a while, but they used to be cheap on eBay and in parts yards. The stock parts don't go bad all that often - I think I've only seen one that was sort of failed, and that was due to a whole lot of corrosion.

Unless you're going for an exactly stock show truck, I'd also install a relay to power the lights - for one thing, you'll have better lighting. You also won't have the full lighting current running through your dashboard. This was a stupid idea on GM's part, and one they didn't correct for a long, long time.

Thanks for the responses. I'll be troubleshooting this problem more this weekend. I was more wondering if you guys are finding that the aftermarket switches are failing prematurely.


Would this relay be installed pre the highbeam selector switch? Do you have any specs for that relay so I can go and buy one? Thanks

about headlight relays ... I've never found them necessary with the stock lighting, but might be useful if you use higher power headlights ... and I haven't had the problems you're having with the switch, maybe poor quality repros, the best come from Danchuk, made for the tri-5 cars but same as for the trucks

Bill

The headlights I bought are Halogens from NAPA. I don't know if those are upgrades from Original Factory.

yes, they'll draw more current than the stock type, although that won't have any effect on the dash light portion of the switch and if your wiring is new and sound a relay isn't really vital. especially if it's not a daily [nightly] driver

Bill

Just a standard Bosch-type relay, you'd need one for low and one for high. Very good write-ups on the conversion are available all over the place.

http://www.classictruckshop.com/clubs/earlyburbs/projects/head/lights.htm

I've seen pictures of plenty of dash fires in various vehicles caused by having all of the headlight power running through the switch. IMHO it's a serious safety hazard, even with stock-type bulbs. Just a dumb decision on the part of GM's bean counters. At least they actually added a few fuses in 1954.

So after more troubleshooting, I found the problem, it WAS a short in the Instrument Wire Circuit. When the manufacture made this particular harness they decided to leave a HOLE BUNCH of exposed wire where the bulb contact ( button ) was crimped inside the bulb housing. When the bulb was installed it pushed the exposed wire down in-turn making contact with the bulb socket causing a short; this was the case ON EVERY SINGLE INSTRUMENT BULB HOUSING. So my fix was to take some heat shrink insulator tubes and cover up the exposed wire, problem fixed. I am happy I figured this problem out, but I am a little ticked that I had to buy two headlight switched in the process. Anyone else experience this with a Classic Harness???