Hi all,
The headlight switch will activate the 'pop up', and sometimes after a 2-3 second lag the low beams come on, but sometimes not. This is a recent problem, not something that has been intermittent over time.
I fiddled/jiggered with the switch, to try to get the lights to come on, but that did nothing, so I'm thinking its not the switch.
The high beams work fine.
Is there a relay, a corroded [____] whatever, or could it still be the switch?
Has anyone else encountered this problem?
Any advice on tracking it down?

 

There aren't any relays. All the power goes through the power light switch. A common fix it to get the Putco headlight harness. It has relays and uses the power light switch as a relay trigger. This still doesn't resolve your issue. It's either a switch issue or maybe a bad connection on the light itself. I doubt the H4 connector came loose.

 

Hi KCREPU,
Thanks for the suggestions. Both low beams act the same concurrently, so I'm thinking it isn't a corroded connector at the bulbs, but I'll check that out anyway.
If my memory is any good, there are some fusible links in the engine compartment for the headlights and pop up motors. I pulled each out to see if they were corroded, but I didn't see a problem.
(Years ago I had a similar problem when I was driving at night and the headlights turned off and my BAC was slightly not in my favor! I don't recall if they also retracted, but cleaning off the connectors worked so I didn't have to spend the night in a stranger's driveway.)
I think I'll try pulling out the links and jumping them, one at a time, as my next step.

 

One fit for the fusible links is to use BUSSMAN fuses.




https://www.rx7club.com/1st-gen-arch...-532866/page3/



I converted by 1985 fusible link block to a second gen fuse holder.

 

I've pulled each of the fusible links and clipped on alligator clips, to no avail.
One thing I noticed was that even though both the low and high beams won't turn on, I can flash the high beams. I think that indicates that its a malfunction in the combo $$$switch. If I'm reading the electrical diagram correctly, a lack of power to the combo switch's "either/or" part kills both, but flashing the high beam is still there because that's a different route within the switch.
Okay - I just did a major wiggle session (flicking the switch between low and high) and got both back on. But this does not bode well for the switch. And from what I'm seeing out there, a combo switch with cruise control on it is not readily available.

Internal "either/or" part of the combo switch is highlighted

 

Yep - you need to clean/replace the combo switch.

 

Here's what it looks like disassembled.
Once you get the combo switch out of the car there are 3 screws that hold the headlight switch, then that comes apart with the 3 snaps the green arrows point to.
Then all the contacts can be accessed to clean.
What's not pictured is the spring loaded ball bearings that make the switches click into place, they will fall out and run away so take it apart on a clean table.
Also the brass horn contact is spring loaded and will want to escape as well.

 

Thanks for uploading that photo j_tso,

I've had that switch disassembled years ago, and the problem reoccurred, so I ended up swapping it out with one I salvaged off an RX7 that was heading to the scrap yard. Its that second one that' a problem now. I guess I'll try cleaning that one out too. And good point on the spring-ball-bearings.
I'll hose it out with a spray of electronics wash. Should I squirt in some di-electric grease around the slide contacts?
I might also buy a new replacement switch. Even if I don't install it (yet), I think it will hold its value in resale later - parts seem to be getting harder to find.