Lost high-beams

[Pierrot Azul 73]

Yesterday, while adjusting the headlights on the coupé, I suddenly lost both high-beams. This happened simultaneously when I was just finishing the adjustment of the right side high-beam.
Now, whenever I switch from low-beams to high-beams, I only get parking lights and the blue light on the dash goes on. When I flash the lights, only the blue indicator and nothing else.
No problem whatsoever with indicators or even additional foglights, and no problem with the rear lights.
My car is an early 1971 US version (2800CS) but the side lights were disconnected and removed.
Any suggestions to find and correct this fault?

 

[jhjacobs]

I just did a quick schematic revue and based on your description it sounds like the high beam relay is not working. The blue light on the dash appears to be controled directly by the switch - it is powered from the same circuit used to activate the high beam relay. It is also possible that there is an in-line fuse between the relay and the battery; a fuse not in the fuse block.

The high beam circuit is very simple; it uses a 4 lead relay. My car is at the body shop so I can't go and find location of the relay for you but you should be able to find it by tracing the wires back from the headlight.

The relay pins are:
30 - +12V in (comes from battery via horn relay - possible in-line fuse)
86 - Control (active at +12v; same signal as blue light)
85 - Ground (should be only used for relay coil - control return)
87 - +12V out to High beams (there should be separate wires to left and right)

 

[Pierrot Azul 73]

Thanks JJ.
As soon as I get the car to the garage I will try that, but it might take some time as I am now moving to a new home.