dash lights and high beams don't work

[porscha356]

Good Day, Everyone,

 

I have a problem that has vexed me for a few days now and I can't seem to find the answer in the datsun forums.

 

First off, everything worked before I removed the instrument panel to re-install the factory tach bulb harness that had fallen out and was now lighting my shoes at night.

Couldn't install the bulbs into the tach while it was under the dash and later discovered that the plastic around the hole had broken in several places and couldn't retain the bulb harness.  So......I proceeded to glue a copper washer in place that would accept the harness.  That problem was fixed but when I put everything back the car would not start...........  Went on the site and discovered the tach needed to be wired in series with the ignition and that polarity might be a problem.  Reversing the white wires on the tach worked and the car started.  However, the dash, running lights, and high beams would not light.  

 

At this point I checked the fuse box, continuity, and ohmed out the fuses, then looked behind the dash for anything I might have loosened or forgotten to re-connect. The headlight switch was next, I pulled it and ohmed the contacts out...........got nothing on the first pull and low beams on the second.  Next, I checked for power to the switch, it was OK.  Then, going around the switch, I applied power from another source to the wire that powers the dash and running lights.  All worked.  The high beams however, did not work.

 

Thinking the switch was bad I took it apart to see the innards.  Simple, electro-mechanical device which looked good but I could not get it to switch on the first pull. So........I ordered a new headlight switch, original brand new Datsun part.  It arrived yesterday and guess what?  It ohms out the same as the old switch and when hooked up doesn't work.  So.........I hooked up a simple, off-on toggle switch from a lawn mower and the dash and parking lights worked but the high beams did not.

 

This car has not been butchered by anyone, the wiring is stock and not modified except for the installation of an internally regulated alternator and the omission of the voltage regulator.  I am the second owner and have never really had any serious electrical problems in the 36 years I have owned the car.

 

Any help out there would be appreciated.  Thanks.

[datzenmike]

The parking lights have to be working in order to be able to have high beams. This is because the power to the headlamp relay is... yup... the parking lights. Without them the relay stays in it's rest position which is low beams.

 

Find your headlamp relay and check the Green/Blue stripe wire. It must have 12 volts on it to work.

Go back to the headlamp switch and check the Green/White stripe wire. It supplies the switch with 12 volts from the fuse box.

 

 

Fuses... ALWAYS REPLACE THEM!!!!!!!! Never trust them. Make sure the brass clips that hold them are clean and making contact. Don't ohm them out. Test for 12 volts on both sides at the clips that hold them, with the headlight switch on.

[porscha356]

Datsun Mike,

 

Thanks for your input.   As always, you were right on the money with the fuse warning.  I replaced them all after the one for the parking lights disintegrated when I removed it.

 

I had checked the voltage across the fuses first thing, in trying to figure out the problem, it was OK.  I should have known if everything was fine beforehand it must have been a simple solution as to why there was no current.  My other mistake was not looking at the wiring diagram to determine current in and current out of the headlight switch.  I found current at the switch from the larger gauge, white w/red stripe wire and falsely assumed it was the only supply.  Therefore, I thought the switch was bad because it wouldn't ohm out through the first pull (parking lights) as it was not wired to do so.  I also misinterpreted the fact that when I applied power at the switch from another source, to the green/white stripe wire, all the running lights worked. That only reinforced my first assumption that the switch was faulty.

 

All in all, I have concluded that when it comes to electricity, I am not well grounded........