1938 Trunk wiring harness questions

[Guest locoincolo]

My coupe had some new wiring installed. It includes pigtails to go to the left/right brake/running lights, the license plate light, and the fuel sending unit.

This is a nice repro harness, with the braided wire and those twist lock style connectors.

I can find plenty of schematic info, but I cannot find details about how these harnesses are run. I see where the clips are, so running the harness through the trunk is no problem. Do I put those taillight twist lock connectors outside of the trunk in the fender? How are the wires supported under the fender?

Here's a pic of the taillight with its current pigtail, and the new pigtail. Should I install the new pigtail where the blue crimp connectors are? If so, the braided cover does not protect the wires through the taillight housing hole (in the next picture), should I put a grommet in there? (yes, is My answer)

After that, does the fuel sender wire come through this hole in the middle of the trunk, or above the exhaust pipe on the drivers side? And again, where should the "connector" go, inside or outside of the trunk?

[Guest Grant Magrath]

Howdy!

That distillery's looking good! I'm at work right now, and I didn't really pay too much attention to the 38 wiring, but the fuel sender wire usually goes across the top of the tank under the car to a hole on the left of the tool box area near the tail light and in to the harness that runs to the front of the car.

And if the tail lights are similar to other GM products of the time, the wires from the tail lights under the fenders should have tar coated heavy cloth insulation on them.

Did you use Rhode Island Wiring? They're pretty comprehensive when it comes to schematics and instructions.

Cheers

Grant

[Guest locoincolo]

Grant, there is a hole in the left of the tool box area, and one in the middle. Sounds like I use the one to the left.

Yes, the wires have a heavy loom for under the fender - you can see the new one in the top of the first picture.

Unfortunately the harness was installed to this point before I got the car- I don't know the manufacturer and have no instructions. Much of it is obvious, my biggest question is where the connectors between the harness and taillight should reside, inside or outside the trunk?

[DonMicheletti]

All the connectors on my '38 Roadmaster are inside the trunk.

Don

[Guest locoincolo]

Thanks Don.

I'm thinking that the holes for the taillight wires inside the trunk are too far forward. THere's a ton of repair. The tar infused portion of the taillight pigtail is far too short to protect the wires fully under the fender.

I think I'll plug the existing holes and make new ones. Any advice is welcomed.

Since I'm not doing a show car, I don't know why it matters to me to try to do things "right"- it's a disease I think.

[Guest Grant Magrath]

I'll see if I can go and check our 38 for you today.

Cheers

Grant

[Guest locoincolo]

Through fits and starts, a few photos, the manuals, and help from you guys I'm starting to figure this thing out. I see where the correct holes used to be for the taillight wiring to enter the trunk in my coupe. I've attached my new pigtails to the taillights themselves, and soon will have the taillights connected (relatively) properly.

One bummer. The PO mounted the RHS (passenger side here) taillight way too high. That is, he used the wire hole as the bottom bolt hole, the upper bolt hole as the wiring hole, and drilled a new hole up high for the upper bolt hole. I guess he used so effing much bondo that it was difficult to remember how the thing went together.

Unless someone here tells me that the coupe taillights were offset by a good six inches from each other I'm going to mount the thing where it fits the holes and the contour of the fender properly.

I asked my family if I should leave it in the wrong place, or move it - and the consensus is to move it - even if I have to fill and touch up a half inch hole. Ok then.

[DonMicheletti]

Loco,

On my '38 46S, The left side wiring is on the trunk pan and on the right, the wiring hole is along the side near the bolt holes. I dont know how to post photos, but if you E Mail me at donmicheletti@cs.com I'll send you the photos.

By the way the car is unrestored and the grommets are still in place.

Don

[Guest locoincolo]

Ok - now I'm wiring the deck lid for the license plate lamp. I'm looking for info or pix about the routing of the pigtail to the license plate lamp from the harness wire in the lid (which I can route properly by using the old one as an example).

Thanks again for all the help - feels good to press on the brake and see a brake light!

[Guest locoincolo]

Figured out the deck lid wiring for the license plate light. Now need to reroute the fuel sender wire to the right hole and get a grommet on it.

Then I need to run an extra wire to one taillight for the turn signal.

After that the rear wiring is complete - time to start up front.

I think I'll replace the single filament bulbs in the front park lights with dual filaments. I can keep the "clearance" lights that way, and get a turn signal. I'll just run those wires separately along the looms. It's not perfect, but it'll work.

Any hints on installing the firewall grommets after all the wiring is in place? Seems like I need to cut them and fit them around the cables. Thankfully I found a box with grommets so I don't have to buy them (sorry Bob's - well, they actually came from you anyway).

Cheers!

[Guest Grant Magrath]

Yeah, you can cut the grommets. If you're keen, you can glue them together with a CA adhesive.

Good idea with the park lights/indicators. The 39 has park lights in the head lights so we got accessory park lights for the fenders and wired them up as indicators. I hope you're up to speed with indicator wiring! It's really easy to get wrong if you're using double filament rear bulbs. Unless you're running separate wiring for the indicators of course!

Cheers

Grant