is it possible to get two bad headlamp switches?

[zschary]

i have to be wrong here..
i was trying to get 12 volts from the brown wire going to the taillight circuit on the firewall from the headlight switch, i checked the switch and i could only get 12v from one of the other tangs for the harness so i got another unit.. doing the same thing so now i figure its user error? I ran a headlamp relay system and that is working and it uses a few wires from the old harness, but it seems like i cant get power through the switch on the dash to anything else.. could use a hand here

[LockDoc]

Originally Posted by zschary

i have to be wrong here..
i was trying to get 12 volts from the brown wire going to the taillight circuit on the firewall from the headlight switch, i checked the switch and i could only get 12v from one of the other tangs for the harness so i got another unit.. doing the same thing so now i figure its user error? I ran a headlamp relay system and that is working and it uses a few wires from the old harness, but it seems like i cant get power through the switch on the dash to anything else.. could use a hand here

Check this electrical FAQ thread out.

http://67-72chevytrucks.com/vboard/s...d.php?t=815300

You may find your answer there.

LockDoc

[zschary]

i looked through that stuff.. thank you ..

Not too much has changed inside the car as it relates to the headlight switch except the switch itself.. But to ask a more focused question.. If i have the headlamp switch in my hand off the car and use an ohm meter across where the hot red wire and the brown wire plug in without the harness connected, it should have continuity right?

[LockDoc]

Originally Posted by zschary

i looked through that stuff.. thank you ..

Not too much has changed inside the car as it relates to the headlight switch except the switch itself.. But to ask a more focused question.. If i have the headlamp switch in my hand off the car and use an ohm meter across where the hot red wire and the brown wire plug in without the harness connected, it should have continuity right?

Sorry, I can't answer that. I tried to make a test harness to test the headlight switches and I didn't have any luck getting it to work.

I think some of that stuff relays through the turn signal switch. Maybe another member will chime in on the question.

LockDoc

[zschary]

thanks, i appreciate it.. Not sure how else it would work but i like learning new things like this.. I mean, it is a switch, it would make sense that when you activate it it simply connects the two blades, but i have been wrong before.. So before i buy a third switch ......
i did read on here that some of these new switches suck, so if it is bad its the second Delco..

[LockDoc]

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Here is a post from vettevet.

There is a plug in the firewall just behind the distributor that carries all the rear light wires. The brown wire is the tail light wire. Check it for power when the HL switch is on.

If you want to test the tail lights, and the headlight switch, you could pull the headlight harness plug off the switch and jump between the red power wire, and the brown tail light wire. If they don't work then there is a problem with the brown wire to the rear lights.

If the lights work, then jump between the orange wire and the brown tail light wire. The orange wire is actually the feed wire for the tail lights. If the tail lights work then the headlight switch is bad.

[RustyPile]

Originally Posted by zschary

i looked through that stuff.. thank you ..

Not too much has changed inside the car as it relates to the headlight switch except the switch itself.. But to ask a more focused question.. If i have the headlamp switch in my hand off the car and use an ohm meter across where the hot red wire and the brown wire plug in without the harness connected, it should have continuity right?

No, that's not right.. The red wire provides power only for the headlights..

Originally Posted by LockDoc

-
Here is a post from vettevet.

There is a plug in the firewall just behind the distributor that carries all the rear light wires. The brown wire is the tail light wire. Check it for power when the HL switch is on.

If you want to test the tail lights, and the headlight switch, you could pull the headlight harness plug off the switch and jump between the red power wire, and the brown tail light wire. If they don't work then there is a problem with the brown wire to the rear lights.

If the lights work, then jump between the orange wire and the brown tail light wire. The orange wire is actually the feed wire for the tail lights. If the tail lights work then the headlight switch is bad.

To expand on what vettevet explained: There are two power feed wires to headlight switch.. One is red, the other is orange.. The orange one comes from the fuse box (fuse is labeled "tail lights") and provides power through the headlight switch for the tail lights and dash lights.. Two sets of contacts control all those lights.. This explains why the "first pull" on the HL switch turns on the tail lights, and the "second pull" turns on the headlights.. The red wire, protected by the fuse link passes power to the headlights through one set of those contacts.. The headlights are protected by a current sensitive circuit breaker that's built into the switch.. The orange wire is protected by the fuse in the fuse box... Power is passed through the second set of contacts into the brown wire for the tail lights..

Follow the test procedure outlined by vettevet and you'll find the problem with your lights.. Tracing all these wires on a wiring diagram will help clear things up for you..

[zschary]

i will work on it today,
i will check the fuse on the tail lights.. i replaced it a few days ago, maybe i pinched that wire putting the kick panel cover on.. (wiring diagram says it feeds the dome too) I will turn my focus to the orange wire.. thank you

[BigBird05]

To answer your first question Yes you can get one or more bad switches. Go to a different store that sells switches from a different company or at least get a switch that is from a different batch. Sometimes parts from the same batch are all bad. ( recall) situation. When returning a bad part I mark the box so I know that they aren't reselling a bad part.

[zschary]

i think i found it.. Thanks for all the help.. The breakthrough was knowing the orange wire provides power.. I pulled the new fuse from the taillamp circuit that i had put in there, and it was ok, but i put it back and bam it worked.. So.. i guess my fuse box is not making a good connection.. or maybe its behind the box .. i am hoping its just dirty.. either way i think i have it.. Probably should clean or spray the little spring keepers with something
thank you
Zach

[LockDoc]

Originally Posted by zschary

i think i found it.. Thanks for all the help.. The breakthrough was knowing the orange wire provides power.. I pulled the new fuse from the taillamp circuit that i had put in there, and it was ok, but i put it back and bam it worked.. So.. i guess my fuse box is not making a good connection.. or maybe its behind the box .. i am hoping its just dirty.. either way i think i have it.. Probably should clean or spray the little spring keepers with something
thank you
Zach

Good deal. Glad you found it. Yes, those contacts can have a coating of rust on them. I used a small ball stone on my Dremmel to clean a couple of mine up but I can't find any more of the small round stones. I think the ones I had were 3/16".

LockDoc

[zschary]

good idea.. i need to make sure its ok, taillights are tough, you never know it if they go out.. important fuse i guess
thanks
Zach

[RustyPile]

Originally Posted by zschary

good idea.. i need to make sure its ok, taillights are tough, you never know it if they go out.. important fuse i guess
thanks
Zach

That's a close statement, but not totally correct as there is a way to know if/when the tail lights go out.. The dash lights are fed from the tail light circuit.. The dash light fuse is "down stream" from the tail light fuse.. If the tail light fuse blows, the dash lights also go out because there is no power to them.. If the dash lights suddenly go out, the first fuse to check is the tail light fuse..

[zschary]

good to know... glad that is the case.. thank you .

[72bowtiestepper]

Originally Posted by RustyPile

That's a close statement, but not totally correct as there is a way to know if/when the tail lights go out.. The dash lights are fed from the tail light circuit.. The dash light fuse is "down stream" from the tail light fuse.. If the tail light fuse blows, the dash lights also go out because there is no power to them.. If the dash lights suddenly go out, the first fuse to check is the tail light fuse..

Good info. RustyPile....Thank You !

[Andy4639]

You should be able to take the switch out of the truck and use your voltmeter/ohm meter and check it for continuity between the different connections on the switch.

[zschary]

i did put the probe on the red, but was not getting continuity, (i think to the brown wire) but as mentioned above i believe some of the lights that i was having trouble with are fed by the orange wire not the red, and the issue was actually the fuse on the orange wire.. which terminals are fed by the red wire? maybe everything else ?

[Andy4639]

Originally Posted by zschary

i did put the probe on the red, but was not getting continuity, (i think to the brown wire) but as mentioned above i believe some of the lights that i was having trouble with are fed by the orange wire not the red, and the issue was actually the fuse on the orange wire.. which terminals are fed by the red wire? maybe everything else ?

Change the red probe to the orange then and check it. Do both to see which ones are feed by each input.

[zschary]

i will try it on the one i took out that i thought was bad, now having second thoughts.. I'll bet the orange wire will have continuity with the middle brown..

[zschary]

no continuity between red and tail light brown.. But yes on orange to brown.. I think all these switches are ok..

[Andy4639]

Originally Posted by zschary

no continuity between red and tail light brown.. But yes on orange to brown.. I think all these switches are ok..

Yes that should be right.

[zschary]

great.. thanks for all the help
Zach