All of the headlights went out in my Catalina tonight on my way home. I left the car in Ace's parking lot.
The fuse diagram has no fuse for the headlights, and something online says there is a fuse in the headlight switch of GM B-Body cars, but gives no further info. Has anybody heard of this before? The only way to get at that switch that I'm aware of is to pull the whole dash trim piece off.
Yes, AMC uses the same headlight switches, I think they do have an internal fuse or breaker though I've never had one blow. Here's some info on testing:
https://www.youtube.com/watch?v=ryuwnYO9GUw
I'll have to pull the unit out when I get it back to the house tomorrow morning. I may just replace the whole switch and be done with it.
I was gonna rig up a couple wires directly from the battery through a fuse to a single headlight to get it back home. My girlfriend came and picked me up before I could assemble everything. Haha.
Also, I highly recommend a headlight relay wiring harness to improve headlight performance and reduce strain on the headlight switch.
Do they make those for these old cars? It has no relay, as you probably know. The headlights are wired straight into the switch.
I'm definitely look into adding that. I'm pretty sure this switch has some kind of internal trouble. Twisting the dimmer flickers the backlights to the cluster and will go out if twisted into certain areas.
If you look at the construction of the headlight switch the dimmer is a simple rheostat with a wiper contact that slides across resistance wire wound on a ceramic substrate. You could try cleaning that stuff up with some fine emery cloth, but I would just replace the switch with a new one and install a relay harness. (Those do tend to come with cheapo relays but they can be easily replaced with better ones.)
I found this video a few minutes ago, it has a nice explanationfor everything. It doesn't look like the headlight power is fused. The headlight power looks to go through the dimmer switch on the headlight dimmer switch before going to the plunger.
The dimmer switch was the problem. It was corroded, I turned the headlights on and checked the connector for power with my multimeter to see if I needed to take the top of the dash off. There was 12 V to the connector, so I put in the new switch, then turned the lights on. They work.
Ah, the dimmer switch - easy to overlook when there's a headlight problem!
Another coworker of mine is an old timer mechanic. He grew up under the hood with his father and grandfather. He said when the highway control first went out that the dimmer switches in these old GM barges were notorious for going bad like that.
Another coworker of mine is an old timer mechanic. He grew up under the hood with his father and grandfather. He said when the highway control first went out that the dimmer switches in these old GM barges were notorious for going bad like that.
Particularly the floor-mounted dimmers since over time they can get pretty gnarly from moisture and crud tracked into the car.