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73-87 Chevy _ GMC Trucks => Electrical => Topic started by: MossyOakSilverado on February 03, 2015, 08:34:10 pm

Title: No Headlights
Post by: MossyOakSilverado on February 03, 2015, 08:34:10 pm

Since I got the truck a couple montha ago, the headlights have not worked, high or low beam. I checked for power at the headlights themselves, nothing. I poped a new switch on that I had laying around and still nothing. The running, dome, and dimmer all work. Would someone happen to know which terminal at the plug is output for the headlights?Also, after power leaves the switch does it go through a relay or fuse? I havent had but a quick moment to check them out and im trying to get all info I can so I can run diag on it next chance I get. Thanks in advance for the help

Title: Re: No Headlights
Post by: Jason S on February 03, 2015, 11:09:18 pm

What year is your truck?

Here is a link to the service manuals (and wiring diagrams): http://forum.73-87chevytrucks.com/smforum/index.php?topic=30115.0 (http://forum.73-87chevytrucks.com/smforum/index.php?topic=30115.0)

Title: Re: No Headlights
Post by: Irish_Alley on February 04, 2015, 01:20:11 am

http://forum.73-87chevytrucks.com/smforum/index.php?topic=29869.msg249998#msg249998
http://forum.73-87chevytrucks.com/smforum/index.php?topic=28492.msg237564#msg237564
http://forum.73-87chevytrucks.com/smforum/index.php?topic=28492.msg237509#msg237509

Title: Re: No Headlights
Post by: srozell on February 04, 2015, 04:47:41 pm

Check your dimmer switch. It can get all corroded and cause shorting issues.

Title: Re: No Headlights
Post by: MossyOakSilverado on March 10, 2015, 06:52:20 am

So just an update, I finally tracked down my no headlight issue. I was checking wiring at the column last night and noticed a plug with three wires, two of which being the green and orange that carry the high and low beam from the firewall to the headlights. I pulled the plug off the bottom of the column and used my power probe to find it had a 12v source from the headlight switch. I ran a jumper wire from the yellow (12v) to the green then to the orange and had headlights! So I plugged it back up and noticed when I click the multi function switch on the column like I would be switching from hi to low beam, yhe plasic piece that the plug is attached to moves back and forth at the bottom of the column. My question is what is that piece and do I have to drop the column to get to it or can it be unbolted from the bottom of the column?

Title: Re: No Headlights
Post by: Irish_Alley on March 11, 2015, 12:19:32 am

does it look like this
(http://contentinfo.autozone.com/znetcs/product-info/en/US/wl2/UDS438/image/3/) (http://www.autozone.com/electrical-and-lighting/dimmer-switch/duralast-dimmer-switch/chevrolet/c10-1-2-ton-p-u-2wd/1984/8-cylinders-l-5-7l-4bl-ohv/19186_0_1985/)
if it does its the headlight dimmer switch just click the picture