hi beam lo beam

[Mr.Meshie]

ok, so, got down to the nitty gritty of the turn signal switch and saw a white plug on the back. this white plug looks to have the space for 3 wires to be soldered onto it. yet i only see 2. a black and a red/white. is there supposed to be a red/yellow on there as well? is this the high beam switch connection?

[Lazeum]

There is a similar problem that happens on the early Z cars where after switching from the low beams to the high beams, or sometimes vice-versa, the head lights shut off, and stay off until you cycle the main light switch from on to off then back to on.

I've experienced this on my 72 Z this weekend for the first time...

I played with the high beam switch and everything went back to normal. I'm following carefully this thread. If I found the reason, I'll post the fix

[Neumeier]

I have had the same problem with my '78 280Z. First of all, it is probably NOT the combo switch or the high low switch. Here is why. A careful look at the wiring diagram shows that the combo switch ONLY provides power to the lamps (BOTH the high and low beams). Also, the left and right lamps are powered separately, each with its own fuse. Here is how the system works. When you turn on the lights, power is supplied to the lamps. The high low switch grounds either the low beam or the high beam (in the steering column area), depending on which position the switch is set to. Also, there is NO relay in the circuit. It is all rather simple. The bottom line is - if either the high or low beams work, it is DEFINITELY NOT the combo switch that is at fault.

Here is where the problem was in my car. Inside of the passenger compartment, on the passenger side just above the carpet on the firewall are two connectors. The black one is labeled C2 in the circuit diagram. In this connector is a red wire with a black stripe (R/B labeling in the diagram). It is the wire that returns to the high/low switch from the head lamps. This metal blade connectors in this plastic C2 housing are either dirty or the wires are loose on one of the ends. You will have to inspect it, clean the connectors, or (in the worst case scenario) clip the wires on both ends and crimp new connectors on them to establish the connection (i.e. eliminating the Black C2 connector entirely). There is only one other connector in this circuit - it is under the steering column on the right side. Remove the plastic cover under the steering column to access it.

My guess is that the C2 connector is often pushed by the passenger with their feet and it affects the wiring. Also, the metal blades in this connector are rather narrow for the 5+ amps required for the headlights.

Good luck!