It's not the fuses

It's not the bulbs

It's not the multifunction switch

It's not the wiring harness connector

It's not the ground

It's not the relay

It's not the wipers (?)

I am hear a relay somewhere else click once when I try and signal left or right but nothing comes on

 

1. Is the dome light working?

2. Did you find the wiring diagram?

 

To me it sounds like half your ignition circuits aren't powering up. Did you check just the mini fuses or the larger ignition fuses under the hood as well? Also, I'm assuming you checked both fuse box locations for any blown fuses????

 

Are you getting power OUT of the multi-function switch? Rear lights are simple circuits, with very little in common, aside from the power source..... There are a selection of splices in the rear circuits, but, none in common..... except for the taillights....

 

What would cause a single click of the turn signal relay but no lights coming on on the dash when I use the turn signal?

 

Bad flasher maybe?

 

That could be I just replaced it it could be bad,

I looked up the schematic, but it seems like the wire colors coming out of the multifunction switch are labeled "nca", so I need to reverse engineer the connector under the dash to get accurate pinouts?

 

What wiring diagrams are you looking at? I use this site, though it seems to be loading slow today..... It shows wire colors as well.

 

That's the site I've been using (very helpful, ty! )

It's looking like I am going to have to re wire everything from scratch in a separate circuit to isolate the tail lights,

To do this I will need to know the wire colors of the multifunction switch, but it appears only the wires in the harness are spelled out,

The wires in the multifunction switch are different, just trying to see how much work I am going to have to do

You see the multifunction switch is labeled NCA (no color associated?) but the wiring of the Dodge (my multifunction switch is labeled GM, Delco, a Chevy product) harness in the van is spelled out

 

Turn and stop lamps will go thru the multifunction switch, taillights should not. If none of 'em work, but the ones in front do...... gotta be where the rear harness splits off from the rest of the wiring.