Schizophrenic headlights

[Doug Meloan]

Recently my headlights have been flickering from high beam to low beam in rapid succession, but only periodically.  Also sometimes when I try to turn on brights they won't come on, and then suddenly they may come on and then flick back off, or may stay on.  Autronic Eye is turned off but need some thoughts on what may be causing this.  Bad floor switch?  Short in system?  Doesnt seem to act up until I try to turn on brights, then it is anyone guess what will happen.

[Russ Austin]

Doug, you just have to reroute the wires. They are routed a different way, than a car without the guide-matic system.  They normally come straight down the fire wall to the dimmer switch.

[Doug Meloan]

Thanks, Russ.  The disconnected 3 pront connector will not reach the dimmer switch so I assume that I need to splice longer wires into this connection, or am I missing something?

Thanks,

Doug

[Russ Austin]

At the guide matic relay, disconnect the 3 prong connector, and run it to the dimmer switch.  That takes the guide matic system off line.

Might as well disconnect the power to the guide matic too.

[Doug Meloan]

Well I cleaned the grounds (which they needed) and that did not solve the problem. I then replaced the dimmer switch, and that did not solve the problem.  Read through the shop manual troubleshooting suggestions and got completely confused so decided to tackle it on another day when I have more time.  I will try Russ' suggestion of bypassing the guidematic next to see if the problem lies with that system but I am confused as to what I am suppose to disconnect and re-connect at the relay.  Do I disconnect the three prong female connector at the dimmer switch and hook another three way female connector to it instead (that normally runs to the relay?) I know I will eventually get this solved (and it is fun trying to solve the mystery), but you all offer the best clues (suggestions)  Thanks.    .   

[Doug Meloan]

Thanks guys for the suggestions.  I will check the grounds and go from there.  I learned a longtime ago to walk away from a project if I start to get frustrated as like you said a solution will eventually come.  I also know that members on this website have always provided good information on where the issue may be.  Thanks again and I will report back with what I find. 

[Russ Austin]

The grounds are always suspect, but I would look at the dimmer switch shorting out at the plug. You can disconnect the guide-matic system, if you think it is malfunctioning.

The normal headlight wire harness runs to the guide-matic relay box. Its on the interior firewall., just left of the steering column.  There are 2 connectors. Unhook the connector that will run to the dimmer switch. Plug it in the dimmer switch, and disconnect the power to the guide-matic.

You can leave the single connector attached to the dimmer switch, as it's just a ground contact.

Start with the grounds, as they probably need to be cleaned up anyways.   Then go to the dimmer switch.

[Jason Edge]

Doug, Tony is spot on with regard to the grounds. Follow the forward lamp harness just through the radiator support grommet and you will see a black wire that attaches to the frame via 5/16" hex screw. If that ground starts to lose contact, the lights will start to flicker. Also check all other grounds. Here is are pictures of the left and right side forward lamp harness grounds:

[Tony and Ginny 429]

I like the way ,you give your car , Human mental health issues
I know the pain and lack of sleep ,some car issues have caused me over the years
Some times , I arrive at my best solutions when I Walk away from a problem to think it out or after a good nights sleep ,I wake with the solution
It is our HOBBY so walk away ,before you allow it to frustrate you ,helps keep thing in perspective and Ejoyable
I would recommend ,that --everyone who owns one of our cars --take the time to go over the car from front to back and clean all grounds and wire connections

[Tony and Ginny 429]

The very first thing to do ALWAY is --clean all grounds-- , associated with the front headlights and the battery
This is always the first place to go ,with these cars
Most times these cars come back to life ,just doing that ,which is a very rewarding experience ( no expense) and a tibute to the outstanding engineering and materials ,that went into our Cadillacs
Grounds get dirty and intermittent ,when a car is this old ,depending on how much exposure the car has had to the elements over the years