electrical and ignition Brake Light Switch Wiring

[7602inBrooklyn]

Please see the attached pic. Happend to notice this on my 76 when I was checking the oil today. It appears that I should have the other spade attached to the brake light switch. but the brake lights function correctly as is. In the realm of leaving well enough alone I didn't connect it. I looked at the wiring diagram but that was no help. 

Should I connect this to the other spade on the switch? 

 

[AustrianVespaGuy]

Well, I'll be honest, I don't quite know what that is in your picture, but I don't think it's your brake light switch.  The brake light switch should be back by the firewall behind the brake booster, where the linkage coming up from the pedal box meets the booster linkage.  Really no guess as to what that is in your picture though. . . :\

 

-Carl

[Hans]

could that be a brake circuit failure warning light sender??

[7602inBrooklyn]

I assumed it was a pressure switch in the hydraulic system for the lights, but yes I suppose it might be a failure sender. I had no idea there was a failure warning light. Where is the light? 

 

The sender is next to the master cylinder in what seems to be a brake system manifold. I suppose I could just hook it up and see what happens. 

[M3M3]

that is not the light switch. light switch is mechanical and is located in the brake pedal linkage on the top/back of the booster mounting bracked by the firewall.

[Mike Self]

The switch in your original picture is unique to the '76s, and warns the driver of unequal braking effort in the two hydraulic circuits, which would happen if there's a leak or other problem in one, which would cause lower pressure in that circuit.  If that switch detects a pressure differential, it will cause your dashboard brake warning light to illuminate, giving it three functions on a '76:  low brake fluid, e-brake on and pressure differential.  

 

The disconnected wire in your picture seems to be brown, which means it's a ground wire for something...and it may be that differential switch...a PO may have unplugged it to turn the warning light off.  There's actually a reset button on the fixture somewhere to turn the light off if it stays on after you fix the problem....

 

cheers

mike

[7602inBrooklyn]

Thanks Mike! That's exactly what makes this place such a great resource. 

[Hans]

Exactly