1976 Seville auto headlight dimmer

[RadSeville]

Hey all.

I have a '76 Cadillac Seville. It has an electric eye under the hood. Car is rather new to me. I was driving last night and manually turned on lights. They were on high beam. I pushed the floor dimmer switch and they dimmed. After that I couldn't get high beams to work at all. I tried lightly pressing switch but that didn't work either. I turned on auto dim and adjusted switch but nothing happened. Today I'm under the hood and find the electric eye laying on a trim piece down below behind bumper. Looks like the small springs are missing from bracket that's still attaced to core support.

Question: Why don't the high beams work?

[rocketraider]

Take it the car didn't come with an owner's manual. Operation of the GuideMatic headlight dimmer should be covered in that including how to manually override it.

 

Trying to remember if the Seville has floor-mounted or column-mounted dimmer switch. They operate differently and my GuideMatic experience is all with floor-mounted dimmers. And even then I haven't messed with one in close to 30 years. 

 

Sorry I can't be more help.

[RadSeville]

It does have an owner's manual, but it doesn't tell why the brights don't work.

[37_Roadmaster_C]

I had a slightly newer Buick Riv with the auto dim headlights. I do not know if the operation is the same, but when the headlight switch was NOT set to auto, the headlights worked like any normal headlight system with a foot switch hi/low system. Not knowing the electrical specifics, I would start by checking the dimmer switch for proper operation. If it checks good the next thing to do would be to get a factory electrical diagram for the car. While waiting for the diagram, check the bulbs, sockets, wiring, relays, fuses and so on.  That was about the time when some manufacturers began to fuse the high and low beams with separate fuses/breakers. It might be a blown fuse for the high beams or a blown fuse for the auto-dim circuits. Good Luck...

Edited April 24, 2023 by 37_Roadmaster_C (see edit history)

[tonyv_73]

Have you tried the basics first? check relays, bulbs, etc? to ensure that its for sure the auto dimming feature?

[RadSeville]

With trial and error, I turned off auto dimmer and I can dom/bright lights with dimmer switch. The electric eye was found hanging and not in it's mounted bracket. All the springs that hold the eye on are gone. That's another project.