Another "no lights thread" 55 2nd 3100

[hb32]

I installed a new factory style harness from Classic in my 55 2nd with an alternator. I have no head lights, tail lights, park lights or brake lights. Suspected the switch so took it out and apart twice but appears good. Filed the breaker points and cleaned the internal contact points. Fuse is blown on the resistor for dash lights but should not effect the rest according to the schematic. Read somewhere that a bad dimmer would affect the head lights but does not explain the rest of the lights. signal lights work and all the bulbs appear serviceable. Horn is also not working but does work when connected directly to battery. No clicking noise at relay. Checked amp meter connections and swapped in a different one, still no joy. Have bat voltage on both terminals of amp meter. Truck will start. Trying to figure out what is common to all in circuit. is my second rewire on one of these trucks and no issues with the first. Any thoughts?

[mr48chev]

I think you are on the right track by doing the process of elimination.

Either the wire that feeds the lights and horn on the fuse block isn't hooked up or there is a bad connection in that circuit.

Will the lights work if you turn the key to Accessory?

Pull out the instruction sheet and see if you can figure out how the fuse panel for the lights is supposed to get it's power and backtrack.

This is supposed to be the stock wiring diagram for that truck. http://chevy.oldcarmanualproject.com...df/55truck.pdf

[OrrieG]

Check your grounding. Should have a #4 ground from cab to battery negative, cab, front clip and bed to frame and frame to battery negative. You have so many things not working that is where I would start. you need good bare metal connections, not just the treads or a sheet metal screw. Once you know the ground is good you can start systematically testing circuits to narrow it down.

[hb32]

Originally Posted by mr48chev

I think you are on the right track by doing the process of elimination.

Either the wire that feeds the lights and horn on the fuse block isn't hooked up or there is a bad connection in that circuit.

Will the lights work if you turn the key to Accessory?

Pull out the instruction sheet and see if you can figure out how the fuse panel for the lights is supposed to get it's power and backtrack.

No fuse panel on this one as it never got that option.Lights won`t work in any position of the key.

Thanks for the input.

[hb32]

Originally Posted by OrrieG

Check your grounding. Should have a #4 ground from cab to battery negative, cab, front clip and bed to frame and frame to battery negative. You have so many things not working that is where I would start. you need good bare metal connections, not just the treads or a sheet metal screw. Once you know the ground is good you can start systematically testing circuits to narrow it down.

I drove the truck home with working lights so really at a loss. Wiring was a snakes nest so figured a new harness was a good thing. Tracing out wires through the stock schematic which this one is suppose to follow. Wondering if the switch to alternator by the previous owner is causing grief? Harness I bought was for an alternator. Need to figure out how pwr gets from bat to light switch.

[tmoble]

supposed to be a 14ga red wire running from one of the two BATT terminals on the back of the ignition switch to the headlight switch. In the wiring diagram linked above they've got two blown up views, one is the ignition switch and the other is the headlight switch. you should be able to get it from there.

[hb32]

Originally Posted by tmoble

supposed to be a 14ga red wire running from one of the two BATT terminals on the back of the ignition switch to the headlight switch. In the wiring diagram linked above they've got two blown up views, one is the ignition switch and the other is the headlight switch. you should be able to get it from there.

So would that be a wire direct or through the harness some how?

[Coupeguy2001]

it uses a separate wire from the ign. to the light switch because of the two bi metallic contacts. If the lights use too much current, the contacts open, cooling down the wire.

[hb32]

Originally Posted by Coupeguy2001

it uses a separate wire from the ign. to the light switch because of the two bi metallic contacts. If the lights use too much current, the contacts open, cooling down the wire.

OK and thanks. I will have a look at that in the norning. Wonder why it is not included in the harness I got or mentioned in the install steps. Easy to see in the factory schematic once I enlarged it.

[justplainray]

heres a photo of my light switch, maybe it will help with the de-bug.
pay no attention to the color code of the wires, it does not match OEM


FWIW
justplainray

[entourageguy]

Is the light switch installed when you are testing it? It needs to be grounded to the dash before it will work.

[justplainray]

Originally Posted by entourageguy

Is the light switch installed when you are testing it? It needs to be grounded to the dash before it will work.

just to clarify...
the headlights and running lights will work if the switch is not grounded.
but the dome light will NOT work if the switch is not grounded.
justplainray

[hb32]

After help from this forum and the stovebolt there are 2 red pwr wires that connect to the ammeter for a total of 3 wires. Pwr to the light switch is off the ammeter and not direct from the switch as shown in the factory schematic. Now my problem is no right brake light which I have determined to be in the signal switch assy as that is where it gets pwr.

[hb32]

Turns out that Chevy runs the right brake light through the signal switch in the column. New switch = brake lights serviceable
Turns out the horn needed a new steering wheel contact.
Next project is the T5 and an HEI dizzy.