Wonky headlight..., back again (post 17) Options

[VaccaRabite]

Last fall, the drivers side headlight went out. it was miswired - I am not sure how it was working to begin with. Fixed the wiring, and everything worked great.

Saturday I washed my car.

Today, I decided to drive to work, even though rain was threatening, weather said I would be clear. But it was cloudy this morning, so I put the lights on. I got no beam from the drivers side light, again.

Also, I noticed that the charging system was right at 12 volts, where it is usually at 13. May be unrelated.

I know that the wiring at the light is correct. Any idea where to start trouble shooting?

Zach

[VaccaRabite]

So, this problem still exists.

I had been letting it slide and just driving my car during the day, but I got caught after dark last week and had a scary drive home

So far this is what I have done:
Replaced all the headlight relays - at the motors and on the fuse panel.
Replaced the high/low relay.
Soldered on new H4 sockets at the ends (I had no sockets, just spades)
replaced fog light switch
Tried running a new wire (test wire) that acted the same for low beams.

High beams work as expected (though they are aimed low as they are my only lights)
Low beams are only getting 6 volts at the bulb.
Driving Lights are not working at all. Need to puzzle that one out.

So I am back at my original question.
What causes a circuit to go from 12 volts to 6 volts?

Anyone got a headlight switch I can borrow to see if that solves the problem?

Zach

Possibilities:
bad headlight switch.
bad ground somewhere between the fuse box and the light.

[Spoke]

Low beams are only getting 6 volts at the bulb.

Goal here is to find where the other 6V is being dropped. Measure each bulb terminal to chassis ground. It could be a couple of things:

1) WRT chassis ground: one terminal is at 0V, the other at 6V: Most likely your switch, fuse, or wiring to each. Do the same voltage tests at the fuse (fuse to chassis). Fuse voltage on each side should be identical (no voltage across the fuse). Measure fuse voltages on the wire spade, not the fuse itself.

2) WRT chassis ground: one terminal is at 6V, the other at 12V: Ground issue to the bulb. Trace the ground wires and correct bad connection issue.

3) WRT chassis ground: one terminal is at 3V, the other at 9V: Combination of both ground and switch/fuse/wiring to each.