Cluster lights/Head Lights not working - Help Please

[jobsforu]

I have a 71 c10. Have new headlight switch and just installed the new Heavy Duty Headlight Harness from LMC. Also replaced all cluster bulbs with new green high light bulbs; aal from LMC. Here are my problems. Any help will be very appreciated:
1. Upon completion of new HD Headlight Harness, headlights worked great. Then I started working on Cluster lights to determine why they would not work; they were before with the old type bulbs. Somewhere along the way, using the headlight switch - I drained the battery and had to re-charge it. But, after the re-charge - the headlights did not work. I have cleaned all of the ground connections and reattached; still do not work.

2. Is there supposed to be a ground wire coming from the gauge panel/circuit board to metal under the dash? If so, I do not have one. Anyone know exactly where I hook it to the back of the gauge panel and where to run it?

3. Also, is there a ground wire from the new headlight switch that I need to connect somewhere? Anyone know what color it is and where it should go?

I have also cleaned all of the battery grounds and replaced. Also cleaned the plugs and connections for the dimmer switch and re-connected. Fuses are good. Yesterday installed new headlights just in case that was the problem. And, I have one wire with a bulb coming from the steering column that appears it should be on the gauge panel somewhere - but have no idea where it goes. And, when I rotate the headlight switch it dims the heater control light so I know that's working. As I said - any help will definitly be appreciated. Thanks, Doug

[70LonghornCST]

Hi Doug,
I moved this to our electrical section for you. Hoping that some of our resident electrical experts will soon chime in.
Richard

[jobsforu]

Thank you Richard. Need all the help I can get.
My Best,
Doug

[VetteVet]

Originally Posted by jobsforu

I have a 71 c10. Have new headlight switch and just installed the new Heavy Duty Headlight Harness from LMC. Also replaced all cluster bulbs with new green high light bulbs; aal from LMC. Here are my problems. Any help will be very appreciated:
1. Upon completion of new HD Headlight Harness, headlights worked great. Then I started working on Cluster lights to determine why they would not work; they were before with the old type bulbs. Somewhere along the way, using the headlight switch - I drained the battery and had to re-charge it. But, after the re-charge - the headlights did not work. I have cleaned all of the ground connections and reattached; still do not work.

Check for power at the blue wire on the dimmer switch with the headlight switch on. If you have it then the HL switch is ok and the dimmer is bad or the wiring to the headlights is open.You'll have a tan and a green wire coming to the left headlight. If you jump power to either of these wires from the blue wire at the dimmer plug both headlights should come on.

If you have no voltage on the blue wire then the HL switch isn't getting power from the battery, alternator junction, or the switch is no good.


2. Is there supposed to be a ground wire coming from the gauge panel/circuit board to metal under the dash? If so, I do not have one. Anyone know exactly where I hook it to the back of the gauge panel and where to run it?

Yes the dash cluster must be grounded. The factory used a small wire with a clip to the cluster, but most of those disappear over the years. You can make a ground easily by just running a short wire with crimped terminals from the cluster to a good ground in the cab such as a steering column mount bolt. The ground to the cluster can be any of the small screws that hold the back together.

3. Also, is there a ground wire from the new headlight switch that I need to connect somewhere? Anyone know what color it is and where it should go?

There should be a white wire on the switch harness that plugs into the switch that is the ground circuit for the dome and courtesy lights. I'll see if I can find a picture.

I have also cleaned all of the battery grounds and replaced. Also cleaned the plugs and connections for the dimmer switch and re-connected. Fuses are good. Yesterday installed new headlights just in case that was the problem. And, I have one wire with a bulb coming from the steering column that appears it should be on the gauge panel somewhere - but have no idea where it goes.

it is a fiber optic cable from the cluster.

This is the light for the shift gear indicator.

And, when I rotate the headlight switch it dims the heater control light so I know that's working. As I said - any help will definitly be appreciated. Thanks, Doug

You have two sources of power to the headlight switch, the large red wire and an orange wire for the parking and tail lights. This is the one that powers the dash lights. We need to separate these two problems but I have an appointment so I'll check back later.

[VetteVet]

Here's the switch.

[jobsforu]

VetteVet:
Thank you so much for your quick replys to my wiring and light problems. Your information and its detail were very helpful. As I was in the garage last evening, I turned on the headlight switch and was fooling around with it a bit and learned that if I pushed the switch handle to the right - the headlights came on and I could dim them and brighten them. So, I concluded that the switch is bad and ordered a new one. If the new one does not work - I will return it. In your opinion, does this sound like the fix I need for not only the headlights, but also for the instrument lights?
Thank you again. I really appreciate your expertise.
Doug Massey

[VetteVet]

Well you control the brightness of the cluster lights with the headlight switch but the headlights don't have a dim to bright feature. They come on when you pull out the switch and shine at the same intensity depending on whether the dimmer switch is set to bright or dim.it sounds like the HL switch is your problem.

I want to clarify the grounding question concerning the headlight switch.
the lug on the switch is not grounded until you turn the switch knob full to the right and then it grounds the lug and the white wire which completes the ground on the dome light to turn it on.

I'm in Charleston S,C.now with a sick family member. Too bad we aren't closer.