my 87 FC3S TII, when I turn on the headlight on low beam both left and the right light is good but when I switch it to the high beam the right side totally no light but the left side is good, I really don't know where to start looking for the problem.can anyone help. thanks !!

 

The High beam is burnt out on that side..it happens.
Replace the headlight with a 6054 sealed beam.

 

thx, but it happen after I change the headlights. is that happen because the relay???

 

wiring??? how??? the low beam works good only one side off when I switch to the high beam. more detail please. thanks

 

If both low beams work but only one high beam then the problem is as follows. There is a relay at the front of the car called the Dimmer Relay and its job is to change the power of the lights from dim to high and back. Now the relay has five wires connected to it and two of them go to the headlights as one is for low beams and the other is for high beams. Now since there are two headlights the low beam wire that comes from the Dimmer Relay has to split into two wires doing the very same thing so each headlight can receive a low beam signal. Now the very same thing applies to the high beam wire which is Red/White (low beam wire is Red/Black). So what is likely happening is the voltage on the high beam wire is coming out of the Dimmer Relay when it is supposed to but the voltage is not splitting in two properly. So with high beams "on" measure for voltage on the Red/Black wire at the high beam which does not work and see if the voltage is present or not. If not then try to trace down the problematic wire and locate the trouble spot.

 

thx a lot, it really help~~~~~