The Stovebolt Site Forums The Shop Area The Electrical Bay No brake lights- what am I missing here?

Here's the facts:

1. 1957 Panel Truck
2. New brake light switch is mounted in truck
3. New wire harness
4. Fuses are in fuse block for parking lights, turn signals, and brakes
5. Testing with one of those square trailer lights

I see no voltages on the brake light switch wires nor the wires that go to the back lights. I had the ignition turned to on, but did not have it running. Pretty sure these lights should work even when the truck is not running, right?

Wish I knew why this truck fights me so hard.

Would you please post your wiring diagram AND any modifications you have made?

Have you checked for a blown fuse?

Thanks for the response. No mods made, brand new fuses. The harness is a Speedway Motors 22 circuit harness. I will find a link to a diagram, but there are 2 wires that go to the switch (brown and white), and then 3 wires to the back for turn signal, stop, and running lights (yellow for left, green for right, brown for running.

Link:

https://www.google.com/url?sa=t&source=web&rct=j&url=https://static.speedwaymotors.com/pdf/91064022.pdf&ved=2ahUKEwil3rP70fzwAhXXSzABHcSUAucQFjAAegQIBBAC&usg=AOvVaw0Mbw-Oj8L5zZO7mSZxwot2

Correct URL: https://static.speedwaymotors.com/pdf/91064022.pdf

Thank you, apologies.

This is a universal wiring kit so it's not a custom fit to your 57 which I suspect your already know.
Are you using the 1969-74 GM column as noted in the instructions?
If not then it looks like you have additional wiring to do.
If you have added the wiring, would you please provide a diagram of this wiring?

Note in the instruction:
This kit was designed to function with a factory GM style
switch and column plug. It plugs into the 3-7/8” plug found
on GM columns from 1969-1974. It is found on a majority
of after market columns including Speedway’s Tilt Columns
such as p/n 910-32972
If you are using a later 1975 and on column we have
included a connector to convert over to the required style.
The columns use the same pin out locations making the
swap easy; please follow the wiring table below to install the
adapter plug on a column.

Thanks for taking the time to review that. No, I am using the stock column. For the brake light connection, I did not think that anything on the steering column would either need to be connected or involved. I figured it would come into play for the turn signals, but not the brakes.

I guess I will have to research this further.

Think about it. The brake light, turn signal and hazard (4 way flashers) all use the same bulb. What controls everything is the turn signal switch.

Do you have a copy of the original 57 Chevy Panel Truck wiring diagram?
Do you have an original or add-on turn signal switch on your steering column?

For the rear lights, the brightest or high element is used for brakes and turn signals and that's why the wiring goes to the turn signal switch.
"IF" your brake and turn signals are a separate light, I would convert to having both in the same light because it is a standard configuration.

For your turn signal connector plug (only applies to a 6 wire turn signal assembly):

Connector G ---- to wire coming from your horn switch (one side of switch is ground and when switch is made, puts a ground on this wire).
Connector H ---- to your turn signal switch wire, left direction (light blue?)
Connector J ---- to your turn signal switch wire, right direction (dark blue?)
Connector K ---- not available in 1957
Connector L ---- to your turn signal switch center or common wire, not ground (yellow?)
Connector M ---- to your turn signal switch brake/rear wire, right direction (purple?)
Connector N ---- to your turn signal switch brake/rear wire, left direction (pink?)
Connector P ---- to your turn signal switch brake feed wire (white?)

I included above what I think is the color code for 1957 turn signal wiring but you need to verify everything to make sure. I am human and easily make mistakes.

Thanks guys, there's a turn signal switch on the top of the column, and earlier this AM, I did find a wire diagram for the '57 TS circuit. After work today, I'm going to compare the diag to the sliced and diced old harness currently in my column, but at first glance, it appears to match.

That said, I guess the next thing on the purchase list is a new TS switch. It's $150, and doesn't even include the turn signal lever, lol. I wish it were a '56 truck, bc then I could say it did not come with turn signals from the factory!!! Eesh.

If you have an original turn signal assembly and it works, or could be made to work mechanically, then I would just replace the switch inside. It's about $20 plus shipping. You have to remove the steering wheel. The old mechanical parts may simply need degreasing and cleaning. Check shop manual from type grease required.

The problem is with the wiring connectors/connections.
If the 57 is like the 54 and 55, the wiring from the switch goes inside the steering column and comes out directly underneath the dash.

option 1: Call Speedway or whomever you purchased from and see if they offer a mating connector with wiring and contacts. It's called a "pigtail". You would clip the 57 connectors and hardwire (solder the wires together and heat shrink) to the pigtail.
option 2: Clip the wiring harness turn signal connector and install 57 type mating connectors (if they are available) to the new switch.
option 3: Don't use any connectors. Hardwire only. The downside is if the switch ever fails, it will take longer to replace.

Thanks! I did wonder if the OEM one could be rebuilt, since it's already there. It just looks a bit tired. The wires that are on the OEM one actually do come out at the floor on mine, so I don't know if maybe it's an aftermarket one or not. I'll have to get some pics later today and load them here.

The harness kit came with a few different connectors, so I'll have to check and see what is there.

I went ahead and ordered a new turn signal switch, and a TS lever, from Eckler's yesterday. I'm going to see if that resolves my debacle before going and ordering a whole cup assy blah blah blah. Stay tuned.

Heads up, this information may be of interest only to those who want to use a modern configuration wiring harness and keep the original steering column.

I interchange the word "pin" with "connector".

There isn't a pigtail available on the market that will connect to the 3 7/8" plug of the turn signal circuit of the 910-64022 wiring kit. The kit is originally made by American Autowire (AAW). AAW does make a 1955-59 Chevy/GMC complete wiring kit but here again the kit is for an early GM steering column (1969-74) with the same 3 7/8" plug. If you want to keep your original steering column, AAW provides an adapter (basically the opposite gender plug) but it is not prewired. You cut off the old wires from the 1955-59 plug of the turn signal switch and crimp-on the provided connectors that push into the adapter. You could simply hardwire the connections and not use plugs but if you ever needed to do maintenance on the assembly, it would be nice to simply unplug the connection.

Jegs has a kit 555-10408 that includes the parts needed.

Crimping connectors on wires is an easy task as long as you have some kind soul to show you how it's done. For a good crimp you need a ratcheting crimper ($100+ ones like Amphenol are an overkill), with a die, made for the specific crimping diameter. Too small and you shear the connector off. Too big and the wire will fall out. Some other gotchas. Don't crimp the connector around the wire insulation. You have to put the correct wire in the correct position in the plug. Once it clicks in place, it can be difficult to make it release to get the wire out (I use a flattened paper clip to depress the locking tab).

The plug that is physically mounted inside of a 1969-74 steering column is a male housing plug that uses male connectors. This is is the style plug (like the one from the Jegs kit) that will now go to the 1955-59 turn signal switch. The plug of the wiring kit (910-64022) is a female housing plug with female connectors.