Headlight delay?

Sometimes when it is cold outside my headlights take a second to turn on, or sometimes they won't turn on until i blip the throttle. Has anyone seen somthing like this before. The only thing that might be wrong with the electical system is the headlights dim a little at idle but become brighter when i rev the engine.

 

The battery is cold and has high internal resistance and is also probably on its last legs, and the voltage regulator ain't regulatin'.

There is an outside chance that someone installed a generator, I suppose - generator output is sensitive to rpm, hence alternators came along to replace them.

 

Is there a relay in the headlight circuit?

 

I'll try that, having the headlights refuse to turn on would no be fun.

 

Old vehicles seem to have a lot of problems with bad grounds. This goes along with rust and corrosion especially. I'd expect that the headlights are grounded through the body and back to the battery through the lead from the fender to the negative battery cable. If this path has a higher resistance than normal, you would see headlight brightness that depends more than usual on the engine speed.

On my '73, I had aftermarket headlights, and I installed a relay between the headlight switch and the lights. As I recall, there was no relay on the headlights from the factory.

I would also check that all the connections are solid and the grounds good in the regulator-alternator charging circuit.

Another possibility - does the '73 use the same thermal cutout in the light switch that the earlier Jeeps use? I thought I read here that part of the circuit is protected by a thermal breaker in the light switch on earlier Jeeps. The separate fuse box didn't happen until 74 or 75 - IIRC the '73 has just a few inline fuses, like the earlier Jeeps. Perhaps the switch could be getting flakey?

 

Yup, start with the grounds and also the relay contacts. I figure your pushing enough volts when you rev, I suspect the relay contacts. Run a wire from the ground side of the lights to the battery ground. If it is a ground problem, everything will work right. If your losing volts due to a broken wire(near open condition) you may be going past it also when voltage is applied. Get the headlights on, then move a few wires around, if you find the open or possible short, your lights will go dim or out. Wiring, oh what fun...

 

Thanks for your help guys i will check it out this weekend.

 

I turned out that the dimmer switch connections were rusty. thanks for your help.