Cadillac & LaSalle Club Discussion Forum

Cadillac & LaSalle Club Forums => Technical / Authenticity => Topic started by: WTL on May 02, 2018, 09:11:35 PM

Title: Headlights/Brights not working
Post by: WTL on May 02, 2018, 09:11:35 PM
Hey guys, maybe I need a bit of help. 

I have a 69 Fleetwood with guidematic/twilight sentinel. 

The headlights started getting inconsistent.  First, the automatic feature stopped working so I had to use it by pulling the switch out.  Then, recently, a few times while trying to switch to brights at night, both brights and low beams went out.  Obviously disquieting. 

Now, I can't get brights to come on at all.  When I hit the foot switch, both beams go out. 

I checked for continuity in the foot switch, and it seemed l could get continuity from the middle terminal to either terminal beside it, when the switch is depressed. 

I have a fsm, but curiously the colors listed in the diagram are off. 

Is it possible this is the switch, or the TS box?  Any way to narrow it down?
Title: Re: Headlights/Brights not working
Post by: cadillacmike68 on May 02, 2018, 11:35:18 PM
A Lot of these type of problems can be tracked to bad grounds coming of the light's' harnesses. Check there first After you check for 12V at the hot wire to the lights.
Title: Re: Headlights/Brights not working
Post by: cadillactim on May 03, 2018, 11:10:11 AM
Do you have the automatic dimming feature turned off at the headlight switch? When the auto dimming is on the system will control the high beam. If you press down on the foot switch and keep it down the high beam will come on (provided the footswitch us grounded properly). If you have the dimming feature turned off, you should be able to control the high and low beams with the footswitch. If not, then as previously mentioned check your grounds and the footswitch.

Tim
Title: Re: Headlights/Brights not working
Post by: 69Deville on May 10, 2018, 10:52:54 AM
Also, double check and make sure the relay for the guidematic is grounded.