High-Beams Failing

[MIPS]

I had this problem with high and low beams back in 2019 and it turned out to be a bad lug on the headlamp switch. Replaced the switch, recrimped and repaired the harness connector because one terminal had melted out and it was working fine again.

I'm driving early Saturday morning with the high-beams on and it drops out and starts flickering. Yeah that's a fun thing to happen when driving through the mountains! Dash and marker lights seem to stay on but the high-beams, low-beams and the symbol on the dash flicker in and out. Click back into low-beams and the headlights instantly come back. Using OEM headlamps and no relays.
How are the headlights wired that allows all four lamps and the dash indicator to fail only when switched to high-beam mode and work fine if kept on the low-beams?

[Taylor]

My headlights would dim when I switched on the high beams. The low beams were always a little dim but got progressively worse to the point they wouldn’t pass Virginia inspection. I’ll need to go look at it to let you know if I included the inboard ( high only ) lamps in the new circuit when I rewired it. I added a couple relays to remove the high power that was running through the factory switch. I also used a heavier gauge wire for less resistance.

[rmick]

All the current goes through the factory switch and there is a bi metallic contact in the switch if too much current draw goes through the switch the contact heats up and opens the circuit. Since there is no fuse in the system to protect it from a short. Thats why it is useful to install relays in the head light system so not all the current goes through the switch also lights may be brighter since power goes directly to the lights. Also check your grounds for  the lights this would also cause high current draw if you don't have a good ground.

[MIPS]

Surprisingly, I have not yet pulled the cluster apart to inspect the switch and add relays.....
(honestly though can you blame me? Pulling the cluster sucks)

I've been trying to catch it in the act to I could then start probing around but it seems when I get the lights dropping out in the evening, I immediately drive home, put the high-beams on in the yard and...it won't happen. I can't replicate the fault in a controlled environment.

[vangremlin]

You can avoid pulling the cluster by mounting the relays in the engine compartment or near the headlights.  Most of the prewired harnesses to accomplish this just plug into your existing headlight sockets and all the wiring is up front.  It may not solve your problem but I believe the relays are a worthwhile upgrade.  Good luck!

[MIPS]

Looks like that's the path I'll have to take.

It's a hot evening and nice and quiet. I grabbed a lawnchair and a beer, turned the headlights on and waited. Took about fifteen minutes and then I brought out the headphones and a high-gain microphone.
You can hear the Sol-Vac click on and off with the lights (that's fine, it's part of the headlight circuit) but it wasn't until I got in the car I could hear the thermal safety in the headlamp switch was opening and closing, so it's a loading issue and not a bad ground.

[MIPS]

Closing the thread as the modification has been done.



A headlight realignment was in order after the obtuse positioning of the relay kit behind the bucket. The rest of the issues stemmed from ignoring the fault for so long, causing the headlamp switch connector to melt down for a second time. New crimps and new switch (and cleaning whatever terminals were still left entombed in the melted mass of a plug) and we're good again.

[vangremlin]

Looks good!

[AMC of Houston]

For those of you who may need a replacement for the melted headlight switch connector, Crown is repopping those now for the Jeeper crowd - about $15.  Search "Crown J3205596" and you'll find them.

[MIPS]

What do I do about the terminals? Is there a part number available for those or are they still Packard 56?

[AMC of Houston]

Still good old Packard AFAIK.