Head lights

['70GMCStep]

I wanted to run this past you all. I've got parking lamps and tail lights, but no headlights. I put in a new headlight harness and a new headlight switch. It appears to be all grounded right, but the lights don't turn on.

I thought I'd run it past you before I went and ordered a front harness. Kind of got me baffled, but I'm no electrician either. Thanks guys.

'70GMCStep

'65 Chevy C-10 lwb bbw
'70 GMC Stepside

[61_FL_Apache]

Check your connections at the firewall on the engine bay side. See if you have any voltage there.

[Clyde65]

I agree with 61, if you dont have power at the core support, follow the wires back to the firewall. If you dont get anything there, then I would check you headlight switch and how the wiring is done there.

[463]

check for power in and out of you good old dimmer switch. i'am thinking thats the weak point. heres a link on the wire dia http://6066gmcguy.org/headlight.htm

[1Bad62Pro/Street]

Checked Ground wire?


Wiring Diagrams:
http://www.google.com/custom?hl=en&s...iagram&spell=1

['70GMCStep]

Thanks for the advice guys. I'll take this to the garage.

'70GMCStep


'65 Chevy C-10 lwb bbw
'70 GMC Stepside

[protrash64]

I've had the connector at the core support come loose after putting on a new grill. Check connections and grounding if everything else appears to be correct.

[Slow Build]

Originally Posted by 463

check for power in and out of you good old dimmer switch. i'am thinking thats the weak point.

That's where I found my problem.
Have you tried both high and low beams?

[61_FL_Apache]

Your issue is going to start at the headlight switch. Find the pin on the switch for the headlights. Trace that forward thru the firewall to the core support. There should be a plug on the driverside coresupport behind the headlights if I remember correctly.

[markeb01]

It's helps if you also put dielectric grease on all the connectors like at the bulkhead and dimmer switch. It provides a better electrical connection and also keeps them from corroding/deteriorating.

['70GMCStep]

Yeah, I am not getting dim or bright on the headlights. The connection is good at the radiator support and the same result occurs with the new headlight switch and the old one that may have still been ok.

I picked up a voltage checker last night and dielectric grease I will need to pick up. I'll check all that and see where it goes. What I'm needing to do someday anyway is replace the underdash harness as it shows wear and tear. Thanks again for the advice. I'll post what turns up.

'70GMCStep

'65 Chevy C-10 lwb, bbw
'70 GMC Stepside

[61_FL_Apache]

Originally Posted by '70GMCStep

Yeah, I am not getting dim or bright on the headlights. The connection is good at the radiator support and the same result occurs with the new headlight switch and the old one that may have still been ok.

Did you get any voltage at the core support connection?

['70GMCStep]

I'll go home and tinker some more. Using computer at work since mine is getting repairs. I'll see what I find.


'70GMCStep

'65 Chevy C-10 lwb, bbw
'70 GMC Stepside

[nachodog2]

I had a similiar problem on my truck and it ended up being the high beam switch was bad. Installed a new one and they worked.
Posted via Mobile Device

[Clyde65]

fuse?

['70GMCStep]

Hey as far as fuses go, which one do we need? There are many at parts stores that are the same sizes, I am assuming that a 32 volt or lower is fine? I've not done any upgrades yet (wiring is the only thing not new/rebuilt on my truck)

I picked up a set of these today. I might try to post a picture of my underdash harness and see what you all think.

'70GMCStep

[Clyde65]

look at the connector on the FW, I had one of the blade connectors slide back away for the front harness connector back when my truck was original.

[fleetsidelarry]

good luck!

[jchav62]

I've got a similar problem with the '65. Let's see if anyone's dealt with this one. I believe it's the switch, let's see what you guys think. When the temp is cold outside(oddly), I get no power at all the the front of the truck, parking lights or headlights... only gauge lights and tail lights. At first I thought it was ground, but when I realized the park lights didn't work either, I figured the switch... Ideas?

[Clyde65]

connections at firewall is my guess.

[jchav62]

Everytime I'm prepared to test them, they work fine... when they weren't working, that connection was the first thing I checked. It's weird that both the park lamps and head lamps go out at the same time.

[Clyde65]

look into that connection and see if the little tabs are where they should be.

[jchav62]

Wiil do. Thanks!!

[astrochimp]

I just wanted to add, on the '63 the park light go off when there is power to the headlights.
It was the same for my old '67 GTO.
No idea when GM changed them from parking lights to running lights for our trucks.

[John Ragsdale]

(Our first new vehicle--70 Chevy C10 Short bed step side with a 250 in-line) I installed the "Ignitor Electronic Ignition" and "Flame Thrower" coil. I connected the red wire from the "Ignitor" to the pink wire just ahead of the resistor wire at the firewall. The engine fired off on the first key turn. Now when I turn the headlights on the running lights go off. Brake lights, turn signals and emergency lights work when the headlights are on.
What have I done to my lighting system? Thanks, John
First of all I'm in the wrong year. Secondly, I found and rectified the problem. Thirdly, thanks for the forum.