1976 Guide-Matic Stopped Working

[Barry]

The auto dimmer on my 22,000 mile 76 Bicentennial has always worked really well. 2 nights ago it worked perfectly. Last night , no auto function. When I depress the foot switch half way I can hear the normal relay click , but they will not stay on high beam even if i turn the sensitivity dial to the near setting which would put them on high. Is there any repairing this, as I like all of the gadgets to work as they should. Any help will be greatly appreciated ! Barry

[mechanic80]

My 77 Guidematic stopped working at the same time as the dome lamps quit and the footwell lamps stay on ALL the time.  I know this is an issue on Sevilles and when the weather gets nicer, Ill spend a few weekends tracing the short.
mechanic80

[Barry]

All the other lighting functions are working on mine, just no auto function. I have the feeling it's on dim and not getting a signal to go to high.

[Glen]

On the earlier Guide-Matics pressing the dimmer switch was only a momentary signal to the on coming drivers.  To switch from dim to automatic you had to press the switch all the way down then release it.           

[cadillacmike68]

The original guide-matic requires you to have the HI beams ON via the foot switch, and the system will kick them into LOW when a bright enough light hits the sensor. Usually a failed sensor will cause the beams to stay on high.  I went through so many sensors in my 1970, I just stopped using it. My 1968 does not have it.

Try this sequence:

Turn your headlights ON
Turn the Guide-matic OFF with the instrument panel switch
Your HIGH beans should be ON at this point
If not, use the foot switch to turn the the HIGH beams ON
Then turn on the guidematic using the instrument panel switch.

If its during the day, your lights should instantly go to LOW beam. If they do, then block the photocell sensor completely and the should go to HI beam. If they don't then the sensor might be bad.

If it's night they should stay on HI beam. Shine a bright light (another car) into your sensor and they should go to LOW beam.  Again, if they don't then the sensor is likely bad.

[Barry]

Is there any such thing as having the photo cell repaired ? They look pretty well sealed !

[cadillacmike68]

Did you follow my sequence Barry? The cells are sealed because being under-hood items, they are in a crappy environment. They get hot and cold (very hot and very cold) and they just give out.

If you are pretty sure its the sensor (it always was in my 1970) then try to find a working used one. feebay may have one,or put a WTB in the proper place here. Ted Holcombe might have one, he used to have entire kits.

[Barry]

Thanks, Mike. Yes I did. Still no automatic return to high beam even with the sensor covered. I can still use the half-touch or full lock down of the foot switch for highs. Gonna play with it a bit more--it worked so well !

[R Schroeder]

Barry,
I have a 1977 repair manual here that says there is a relay in the circuit.
I dont know if that helps or not, since yours is a 76.
If it has one, it could be that it burned out.
Roy

[Barry]

It does have a relay which clicks, but in working on my 61 Continental Convertible, that does not always mean the relay is working ! Thanks for the suggestion !

[R Schroeder]

It could have burnt contacts.
Sometimes you can open them up to see what shape things are in.

[Barry]

Thanks, I'll see if I can open her up !The Lincoln relays can be and I have to do so fairly often !

[R Schroeder]

Don't know if this will help you or not. I did find the testing procedure for the lights.
Now this is out of a 1977 manual, so I dont know if its different from yours , but it may help.

[Barry]

Thank you so much , Roy. Raining today, but I am going to try this. I do have a 76 manual, this procedure seems fairly simple !

[R Schroeder]

I wasnt sure what you had for info, so I put it out there.
Glad it helps.
Roy