Tail light wiring w/o ambulance doors 79’ 40 (1 Viewer)

[Jl33olemiss]

Bought from PO and headlights, flashers, brakes and turn signals all work. Dash, and rear tail lights don’t work while ambulance doors are off. I know the ambulance doors must ground out the lights. Question is how do I ground correctly without ambulance doors. Obviously not experienced in electrical. I have it grounded but it’s not working. See pic. Thanks for any help.

 

[charliemeyer007]

So you checked that ground is actually making conductive contact.

You could easily run a new ground wire to every bulb/socket that's not working back up to the battery. 14 gauge black auto stuff 50' is less than $20.

You should find the wiring diagram for your rig. I had the Haynes one for my 72 blown up to A4 size, then laminated. Should have put all the tune up spec's, part # for stuff like filter, belts, hoses and torque specs on the back before I had it laminated.

 

[pb4ugo]

I'm pretty sure the white wire with the blk stripe is a ground.

 

[Aloha Jen]

Bought from PO and headlights, flashers, brakes and turn signals all work. Dash, and rear tail lights don’t work while ambulance doors are off. I know the ambulance doors must ground out the lights. Question is how do I ground correctly without ambulance doors. Obviously not experienced in electrical. I have it grounded but it’s not working. See pic. Thanks for any help.

View attachment 3494742

View attachment 3494743

Your rear lights don’t work because I think it needs the license plate lights plugged in to complete the circuit (I think). I had a similar issue with rear lights not working because the license plate lights weren’t plugged in. Try to see if the lights work if plugged in and grounded to the body.

 

[Jl33olemiss]

Your rear lights don’t work because I think it needs the license plate lights plugged in to complete the circuit (I think). I had a similar issue with rear lights not working because the license plate lights weren’t plugged in. Try to see if the lights work if plugged in and grounded to the body.

They do work when doors are installed. It is grounded that way. Question is how to over ride this with the doors off?

 

[Jl33olemiss]

They do work when doors are installed. It is grounded that way. Question is how to over ride this with the doors off?

I tried grounding the additional black and white wire and it still didn’t work

 

[Jl33olemiss]

I'm pretty sure the white wire with the blk stripe is a ground.

I found the electrical diagram and I think you are right. Tried grounding that without the door plugged in and still didn’t work

 

[charliemeyer007]

Have you used one of those test lights to see if there is power to the hot side (center knob of single bulbs) with the tester grounded right on the neg. terminal of the battery. Running extra grounds is risk free - its not like they are going to short out or something.

 

[pb4ugo]

Removing the amby doors and license plate light should not effect the rest of marker lights unless it's a common ground wire issue. The license plate light is wired in parallel, not in series. The rest of the lights should work even when power is disconnected from it. In your pic the blk wire that is grounded is not stock, what's it connected to? You mentioned your dash lights don't work either, which tells me there's no power in the circuit when the marker lights are turned on. I would 1st check the fuse and clean the fuse holder. I'd disconnect the batt b4 cleaning it. As Charlie asked, do you have a test light?

 

[Jl33olemiss]

Removing the amby doors and license plate light should not effect the rest of marker lights unless it's a common ground wire issue. The license plate light is wired in parallel, not in series. The rest of the lights should work even when power is disconnected from it. In your pic the blk wire that is grounded is not stock, what's it connected to? You mentioned your dash lights don't work either, which tells me there's no power in the circuit when the marker lights are turned on. I would 1st check the fuse and clean the fuse holder. I'd disconnect the batt b4 cleaning it. As Charlie asked, do you have a test light?

I’ll get a test light and clean the fuse holder. The fuse is brand new and did not blow prior to me replacing it.