Headlight issue + new guy

[nvr_di]

Hi Guys

This is my first post on this great site! Theres nothing like a group of people with a common love for these beautiful trucks helping each other.

I have a 69 c10 LWB truck that I bought in 2006. its got a 307 I beleive that the PO said he rebuilt before I bought it. it ran great while I drove it but I ended up parking it sometime in 2007 because of gas prices and I cheaply picked up a acura with heat, ac, and a transmission with over drive. Recently the acura was stolen and with gas prices down and me working from home im not driving as much, so i thought its time to get the ol truck running again. And Dam I miss driving it! its not much too look at right now but it sure is fun!

Anyway I put new gas and fluids in and it fires right up! I go to take it for the maden voyage and notice the headlights dont work.
The running lights, blinkers, dome, and brakelights all work but the dashlights flicker and work intermittently. I checked all the fuses and they are good. So I jump on the forum and do some searching and come up with the headlight switch.
I put a new switch in and the dashlights work great now but still no headlights.

More searching on the forum lead me to testing some wires and thats where im stuck and I hope you guys can point me in the right direction.
The headlights work when connected to the battery but the wires running to them have no power.
The Dimmer in the floor has power on the lt blue wire but nothing on the tan or lt green wires. and thats where im stuck. is my dimmer bad or is the problem further up the line?
Ultimately I want to do the headlight relay upgrade but from what I understand I need to see power on the tan and/or lt green wires correct?

Thanks in advance for the help and thanks for making this site such a great place!

Tim

[71MUTT]

I've had my truck for over 30 years and twice I had the headlights quit. Both times it was the dimmer switch. Replaced it and all was well.

Welcome to the forums

[1970cstblazer]

Usually the floor mounted dimmer switches are the culprit. It is entirely possible that both bulbs are blown, but not likely.

[oldblue1968chevy]

try teh dimmer switch mine went out too 7 bucks to replace at autozone etc

[VetteVet]

Pull the plug on the dimmer switch and jump between the light blue wire and the tan one or the light green one, and if the headlights work then the dimmer switch is bad. There are no grounding issues with the dimmer switch to worry about.

[nvr_di]

Thanks for the welcome guys and the information!

I was leaning towards the dimmer switch being the problem until now..

Originally Posted by VetteVet

Pull the plug on the dimmer switch and jump between the light blue wire and the tan one or the light green one, and if the headlights work then the dimmer switch is bad. There are no grounding issues with the dimmer switch to worry about.

Ok so went out and tried this on both the tan and lt green wires and got nothing.
I also hooked up one of the headlights directly to the battery and it worked. So I know at least one of my headlights is good.

So from what I can tell from the wiring diagram, if I jump the dimmer switch plug and nothing happens that means there is a break in wire between the dimmer plug and the headlight?
Or a possible ground issue?
That is of course if I am reading the diagram correctly.

Thanks again guys!

[BigDaddyDave]

Welcome to the board from NC!

[Andy4639]

VetteVet,

Pull the plug on the dimmer switch and jump between the light blue wire and the tan one or the light green one, and if the headlights work then the dimmer switch is bad. There are no grounding issues with the dimmer switch to worry about.

This is just one of the wires jumped not both. If you put the jumper back in place of the tan & light blue then disconnect the head light socket and check for power in the socket with test light. I had to replace both sockets on my 71 because the 30 years plus they had melted and weren't making contact with the bulb connection.