In need of wiring help
 

I am sure the answers to my question are already some where in thread but here goes. Are 72 C20 is driving me bananas. The side marker lights in the front fenders don't work there is power on the brown wire side of the pigtail. So I thought okay it's a ground issue so I un taped the wiring down down the as far as I could to discover the ground wire for the pigtail is factory soldiered to the blue turn signal wire for the marker light in the front bumper. As I have discovered from reading on here the side marker lights are supposed to flash on 71 and 72 pickups when the turn signal is on. So my question is where is the ground supposed to come from for the light to work?

Re: In need of wiring help
 

I dimly recall that the ground for the turn signals goes through the marker lights, and that that is what makes them alternate. I'm hazy on the details, and I don't think that my truck has this feature. Somebody with more knowledge should be by soon to clear it up.

Re: In need of wiring help
 

They don't have a ground really. They get a lower-than-12V signal through the front turn signal/parking lights. Make sure the front turn signal/parking light assemblies are grounded properly.

Try taking out the LED bulbs from the front turn signal/parking lights and from the side markers, and put regular incandescent bulbs in and see if it works. Try them with headlights off and turn signal lever on on, then with headlights on and blinker off, then with headlights on and turn signal lever on.

The going-bananas option comes at no extra charge with LED bulbs. :-)