Electrical: Tail light wiring '57 Scotsman. Frustrating.

[Pepse]

I think I am missing something in what I am doing. I got new tail light harnesses (installed in the housings) and proceeded to connect them to the rear harness from the frame. The tail light harness has 2 wires and the frame wiring has 3. I know the black wire from the frame harness is for the backup lights. So, when I connect the 2 wires from the tail light harness to the frame harness I have nothing, but if I take a wire for the tail light and ground it to the frame I have a tail light. What am I missing?

Later. Pepse.

[StudeRich]

A few Nomenclatures need to be clear here first.

The Wire from the Tail Lamp Assembles are just 2 wrapped "Wires", one for Tail Lamp and one for Stop and Turn. Not Harnesses.

The "Rear Wire Harness" from the Dash area has the Red Fuel Sending Unit wire, a Left Turn, a Right Turn, a Tail Light (usually Black with a Yellow Tracer stripe) Circuit to both Left & Right, the Licence Light and a unused back-up light Wire on Scotsman.

Of course at both of the Tail Lights you would only see the 3.

In order for the Tail light to come on by Grounding a normally "Hot" when switched on wire, there would have to another "Wire" from somewhere attached to the Tail Light, unless you are seeing Sunlight, not a Lit Bulb!

So WHAT wires were connected to the Tail Light and WHAT was turned on at the dash for the "Testing?

Was the T/L Housing mounted and Grounded?

Were the Turn/Stop wires at the Steering Column from the Main forward Harness to the Turn Signal Switch properly connected?

UPDATE: OK on review 4 times of your Post #1, I realized that maybe what you did not say is: the Tail Lights OR on the side you tested, the Turn Indicator was ON (AND the Ign. Sw.) were switched ON, so one wire was Hot and grounding the other gave it a course to Ground through the other Bulb filament to Light one of them and the Bulb, Bulb Socket or T/L Housing was not grounded.

[Pepse]

Okay I went out to the car and wrote down the taillight wiring. Left side: taillight wires green/white stripe and white, wires from frame harness: white/green stripe, black/green stripe, and brown. Right side: taillight wiring green/white stripe and white, frame harness: black/green stripe, green, and white/black (or green) stripe. The taillight assemblies are mounted to the body. Also, there is a black wire in the middle of the rear frame that I am sure is for the license plate light. Using the headlight switch in parking light mode. I can only do the taillights as the wiring harness under the dash is mostly disconnected from the steering column. Not sure why my father-in-law did that. I did take pics of the wiring. The wires coming out of the firewall don't exactly match the wire colors from the steering column. I have a wiring diagram but I can't figure out the area I need to work with.

Another note. This car was stripped of all external things like taillight assemblies, headlight assy's, trim (what little there is on a Scotsman) license plate bracket and license light housing, bumpers, and the housings that the front parking/turn assy. signal goes into and a few other things like the wiring under the dash that I mentioned. I have put most of the parts back on the car except the front panels that hold the park/turn assy's., because the front bumper is bent and I can't mount the left panel.

Hopefully I got everything needed at the moment.
Later. Pepse.

[rockne10]

Jim,
FWIW, you might want to procure the Shop Manual, Body Catalog and Chassis Catalog. It sounds like just having a wiring harness schematic would benefit you greatly.

[Pepse]

I do have those manuals on a CD ROM. Like I said I have a schematic but it doesn't help me as to where the wires are coming from and going to the steering column. I would hope one of those 3 manuals would have pics of the area or something besides the schematic that would direct me to the area in question. Probably hoping for too much. Also, it is a pain in the dupa paging through these manuals on CD to try to figure out which one has the info I need.

Later. Pepse.

[StudeRich]

Without the Parking lights grounded and connected to the Turn Signal Switch through the Flasher, the Rear Turn Signals will either Not Light, or Flash rapidly depending on a Std. or H.D. Flashing Unit.
So that is ONE reason why the Rear Turn Signals do not work and why the Tail Lights do.

[TWChamp]

I always buy the 3 books for my cars. I don't like using CD's.

[doofus]

Pepse, borrow a print copy of the wiring diagram, have it blown up to 48x48 in . tape to some cardboard. priceless! Luck Doofus

[52-fan]

Pepse, borrow a print copy of the wiring diagram, have it blown up to 48x48 in . tape to some cardboard. priceless! Luck Doofus

This helps me too. I always enlarge whatever area I am working on and sometimes I use colored pencils to trace the wires I need to work on. This makes it much better than trying to follow the black lines on the original page.

[TWChamp]

I've seen colored Studebaker wiring schematics on ebay.
I take my wiring and lubrication chart pages to the print shop and have them enlarged.

[Mike Sal]

Taillights on a Scotsman.....I figured they just used candles or a barn lantern....

[Pepse]

Yes Mike Sal, it has real taillights. 12 volt bulbs even.
Anyway, it looks like I need to ground the black backup light wires to the taillight housing and theoretically I should have lights.

Later. Pepse.

[TWChamp]

Yes Mike Sal, it has real taillights. 12 volt bulbs even.
Anyway, it looks like I need to ground the black backup light wires to the taillight housing and theoretically I should have lights.

Later. Pepse.

Did I miss something here?
This doesn't sound right. If you have a backup light wire, it's to power the backup lights, if you have them installed.
It's not to supply a ground for other lights.

[Pepse]

So then the 2 black wires are to be grounded somewhere on the taillight housings?

Pepse.

[TWChamp]

Can you post a picture of your car's wiring schematic, or at least the wiring for the taillights?
I don't know of any steel bodied car that used separate ground wires to the taillights.
The body acts as the ground side of the circuit.