No Headlights?

[seattlejester]

Hello folks,

I was hoping to find some help with getting my headlights to turn on.

Right now I'm just testing the wiring harness, so there is no motor in the car, however the starter and alternator are wired into the engine bay, and the battery is on a trickle charger at~11-12volts.

11/1971 240z.

No dome light

No door ajar switches

No door buzzer

No rear side marker

No rear hatch heater

No rear speaker

No antenna

No radio

No heater blower or heater controls

The PO had installed an aftermarket radio, but I'm pretty sure I sorted all that out.

I've checked the headlight and the connecting harness by wiring them directly to the battery so that portion works.

When placed on the headlight switch, all the dash lights, side markers, and brake lights turn on as they are supposed to.

The voltage at the front of the harness is a very dwindling voltage. Sometimes at 11v sometimes it goes down to 0.15 volts. Even when the high beam is engaged, the voltage from 11 volts or so drops almost down to 0 once the headlights are connected, when this voltage drops to 0, the blue high beam light on the speedo turns off.

Voltage at the fuses are 11-12 volts across, but also experience the same draining voltage when anything is wired inline.

I've tried and trace the wiring diagram as best as I could. Do these symptoms speak to anyone?

Edited July 4, 2012 by seattlejester

[slowride]

I had that problem and it was the Hi-Beam switch that needed to be triggered.

Other times it was that the fact that the engine needed to be running also make sure your marker lights screws are not touching any metal

[240260280z]

Check to see if the fuse box to dash wiring harness connector has come loose.

It is right under the radio at the front of the centre console.

It is white rectangular nylon-ish connector with 6 connections

[Carl Beck]

Hi Seattlejester:

Too many things to address at one time in one Post. Just too many variables in that list of items.

I would get the engine in the car and get it running first. Make sure you have all the ground wires clean and attached to clean metal on the body - this is very important. {most likely a cause of your floating power} Then start with one item - and work on that.

You Post was titled "NO Headlights" If you have power across the fuse when all the above is done, then the next place to check is the headlight switch. The contacts wear and corrode with age. Sometimes just flipping the switch on and off several times - will clear enough corrosion off the contacts to pass power to the headlights.

FWIW,

Carl B.

[seattlejester]

Despite all those missing parts, everything is grounded as it should be. Tracing the circuit I come up with this diagram, note I went a little overboard tracing the ground wire.

The problem is that I have power, but it drains. The battery has more than enough amperage with the trickle charger, I checked by running the alternator, and the trickle charger charges faster than the alternator at high drill speeds.

I found this post,

http://www.classiczcars.com/forums/thread643.html

which indicates a faulty ground on the combination switch, but I'm not detecting any voltage from what I think are the grounds. Anyone know where the wire in question from the previous post is?

[Zed Head]

It's hard to figure out what exactly you're describing. I don't even see the "wire in question" in your first post.

You can test the headlight switch directly by taking the plastic cover off of the top of the steering column and measuring voltage in and voltage out at the switch. The wires and their soldered attachment points will be exposed with the plastic cover removed.

Measure from the power input wire to ground, see if you have battery voltage. Turn the headlights on and measure the output wire, you should see battery voltage.

If you have both of those, then move over to the dimmer switch on the turn signal stalk. That is the ground for the headlights, one for low and one for high. It's common for the dimmer switch to get gummed up and not provide a good ground for the high and low circuits, either one or or both. You can spray contact cleaner in the dimmer switch and work it back and forth sometimes, to get the headlights working.

[seattlejester]

Sorry I know I'm not being the clearest. But I just checked as the linked thread said, and connecting the battery directly to the fuse supplying the headlight, provides headlights! So I'm on the hunt for the ground wire in question.

From what I understand, and what the voltages are telling me, the headlights ground through the turn signal stalk.

Specifically this black wire in the middle?

Tracing that wire brings me to this switch, which I'm pretty sure is the headlight/highbeam switch.

The contact in the middle seems to be about ready to fall off, is this the culprit in question? Or is this switch just in charge of highbeams alone?

[seattlejester]

So when I tried to fix the switch above it disintegrated on me (probably the cause for a few headlight failures).

So I hard wired the headlight (RW I believe) and wired it to the ground (black wire). Unfortunately this didn't do anything.

So I kept tracing and went through the right hand combination switch. Took it apart and got to the rocker assembly.

Three things caught my eye.

1. The contact patch was blackened.

2. The brass rocker wasn't sitting straight.

3. The spring loaded nubbin was sitting at different heights with respect to each rocker.

So I grabbed a set of pliers and squeezed the holding points to flatten them out and expand them.

Cut little bits of wires and stuffed them into the cap to raise the heights of the nubbin.

And used a blade to clean away a bit of the blackened patch.

Put it back together, and low and behold, headlights . Now off to do the headlight relay mod.

Thank you all! I know I wasn't the clearest with my problem, but I really couldn't and wouldn't have found the wire in question without your assistance.