Brights not working...

[Gregg Benedict]

Update on this: Again, '68 Imperial with both Safe Guard Sentinal and Auto Dimming. I managed to get a new 4-prong headlight dimmer switch. It was NOS and pricey (~$170). Anyway, I still have the same problem. The brights still aren't working. I've done the test bypass with a length of wire and that gets the brights to work, so I know the lights work. So, what else can it be? Maybe the only other option is to bypass then entire auto-dimming system... any idea how to go about doing that?

 

[Gregg Benedict]

I'm still trying to figure how to bypass this auto-dimming system. It seems like there is an inline fuse in the system which would effectively bypass the system if the fuse is blown or removed. However, I cannot seem to locate it. I can see it on the wiring diagram, but that's it. Any other ideas on how to bypass the auto dimming to make the dimming switch work manually?

 

[cbarge]

I had a 68 NYer with both ststems.
Never did work right.
Put a rag over the photocell on the cowl between the wipers and see iff the brights come on. Make sure the button in daash is set forthem to come on.
But make sure the photocell on the cowl is grounded well. Over the years they can lose ground and check the wiring for any breaks in it.

 

[70bigblockdodge]

Grounds, grounds, grounds.
Your high beams are providing the ground for the low beam or vise-versa. Happens on big trucks a lot with fiberglass hoods.
Run a ground back to the battery. If it makes it start working properly then go clean the grounds.