Brake Switch Wiring

[rrenner]

I'm using a speedway 20 circuit wiring harness and am up to wiring the brake switch, instructions say orange #40b to imput side of switch and white #17a to output side of switch. I am using the stock lever arm switch activated off the pedel arm. My questions are, which contact on the switch is which, or does it matter? The harness does not supply a wire to run to the back, I assume one runs from the switch to the brake lights, from the output side? Any help will be apprecaited. Rob.

[mr48chev]

It doesn't matter, the switch isn't polarity sensitive. In-out / off/on (normally off) in either direction.

[_Ogre]

Originally Posted by rrenner

or does it matter?

no. it doesn't matter

[rrenner]

Thanks for the help guys, seems like the first part of my question is getting answered, but what about the wire to the back, if polarity doesn't matter then the wire running aft comes off either contact on the brake switch? I have searched for a diagram but no luck. On the 1958 wiring diagram I see only 2 wires comming off the stop switch.

[Russell Ashley]

Rob, if you have turn signals the wire from the switch doesn't go directly to the brake lights, it goes to the turn signal switch.

[_Ogre]

speedway uses the same color code as gm standard color codes i believe. also the same as most aftermarket harnesses
there should be 2 connections on the stop light switch: orange power in and white out to the turn signal switch

you have 7 wires going to the turn signal switch: 3 hots in - blinker, hazard blinker and brake light switch, then 4 wires out to each corner of your truck
your brake lights and turn indicators are the same wire out back, plus you have a wire to the back lights off the headlight switch
in the harness there should be a single tail light wire that splits into 2 wires for tail lights and 2 wires LR and RR stop/turn, it may be only written as LR and RR turn
there is a double filament bulb in each tail light; the big bright one is stop/turn and the smaller dimmer one is tail light

what column are you using?

[mr48chev]

Good point made by Russel. Are you running a turn signal switch that allows for the brake lights to run through it? Or are you running separate turn signal lights if you have turn signal lights?

With no turn signals or separate turn signal lights you would just run from the switch back to the brake light side of the tail/brake lights.

With a late model steering column and turn signal switch you would run from the stop light switch to the proper brake light input wire on the turn signal switch.

Some aftermarket clamp on the column turn signal switches have provisions for brake lights and some don't so that would depend on the switch.

[rrenner]

Its all getting clearer, that why this forum is my go to place. I do have turn signals, hope to wire to my stock turn signal switch on original column. I had posted a question about that a while back and Orge came through! I'm not sure what tail lights I'm going to use (don't even have a usable bed yet) but I have some magnetic harbor freight trailer lights to mock up the rear connections. Front buckets are rebuilt and wired, so can test them too. Thanks fellas!

[Russell Ashley]

This might help a little. I'm using an EZWire harness but probably the wire colors are the same as yours since they are supposed to be original GM colors. I am using an original style turn signal switch and here is how I have mine wired. The ribbon cable on the left side of the connector is the cable from my turn signal switch. Notice that the colors don't match in every case.

[OrrieG]

Here are diagrams of the stock turn signal wiring harness. Power from the switch comes from a yellow wire from the flasher. Power to the flasher is fed by a pink wire from the accessory circuit. On stock trucks the flasher is stuffed up under the dash. Stop light switch is feed from the light switch by an orange wire.

[_Ogre]

notice the above pic only has 6 wires for the column wiring (plus horn)
stock harness only had one flasher, no hazard flasher power
post up a pic of your column; there were many different turn signal switches in these trucks
oem cup on column; some with self cancel wheel
signal stat 900 series, especially on the bigger trucks; turn signals were sometime a dealer option

[mr48chev]

Tie those Magnetic HF lights down before you go for a test ride. I've had two different sets bounce on the pavement when I had them on my trailer frame. They work good in the middle of a deck lid though.

The key now is does the turn switch have a provision for brake lights so you can use one bulb or light on the back or is it "turn signal only" as many early ones were and you need separate turn lights or bulbs.

If you have the brand and model (if available) of the switch and the number of wires coming out of it someone might be able to dig up info on it.

[Russell Ashley]

Rob, I just noticed that you are from Chicamauga. I just spent a few days up that way visiting my Bro-in-law near Lafayette. I usually visit him about twice a year and help him bale hay. Lovely country up that way. If you ever go to any of the local cruise ins around there and see a tan 69 Dodge 4X4 that's my old truck.

[rrenner]

Russell, that picture will help a lot. Looks like your setup is what I'm shooting for, is that cleves your e-brake? (did the same thing). This area is nice, moved here from Fl. and work in Lafayette...
I have thought of another issue that involves the brake wiring. I am using a 700r4 and got the lockup kit from Bowtie Overdrives. The diagram has a wire from the relay tapping into "existing brake circuit". Is that one of the turn signal wires Ogre is talking about? The harness also has a third brake light wire that I wasn't going to use, could that be used? Thanks again for all the advise. Rob



bowtie wiring.pdf

[Russell Ashley]

Originally Posted by rrenner

Russell, that picture will help a lot. Looks like your setup is what I'm shooting for, is that cleves your e-brake? (did the same thing). This area is nice, moved here from Fl. and work in Lafayette...
I have thought of another issue that involves the brake wiring. I am using a 700r4 and got the lockup kit from Bowtie Overdrives. The diagram has a wire from the relay tapping into "existing brake circuit". Is that one of the turn signal wires Ogre is talking about? The harness also has a third brake light wire that I wasn't going to use, could that be used? Thanks again for all the advise. Rob



Attachment 1319899

Rob, the clevis is my e-brake cable. I got rid of the original rod and pulleys and got new cables from Control Cables.
I'm not familiar with your Bowtie Overdrives kit. One side of the brake light switch has battery voltage on it all the time while the other side has battery voltage only when the brake pedal is pressed, as Ogre's pic shows. Without seeing the instructions from Bowtie Overdrives I can't say for sure which side they mean.

[rrenner]

Hey Guys, I guess my attachment did not show up, maybe a jpeg will show better. Here is the bowtie wiring daigram. The kit comes with relay and the rest of the necessary wiring and connectors including the stuff that went in the transmission. I'm thinking that 3rd brake wire would work, would'nt that have 12v when the brake is applied, which is what the lockup is looking for? Either that or the wire from the switch that has 12v when the brake is applied.

Russell , did my e-brake the same way, the guy at Control Cable was great to work with..

[Russell Ashley]

I think the "existing brake circuit" wire they are referring to is the wire from the brake light switch that goes to the turn signal switch. I'm guessing that the third brake light wire would work too.
Since your fuse panel has a hazard flasher already it's pretty easy to add the wiring and switch to make them work. I'm away from home now but will do a thread on how to do it when I get home.

[_Ogre]

i drew this up a couple years ago to explain how to cut power to the lockout
if you already have the relay in the harness it is probably wired like this
i needed this for my lockup and cruise control kick out

[OrrieG]

Originally Posted by _Ogre

i drew this up a couple years ago to explain how to cut power to the lockout
if you already have the relay in the harness it is probably wired like this
i needed this for my lockup and cruise control kick out

ground is pin 85, energize signal is 86

[_Ogre]

your diagram and the drawing i posted are basically the same, yours cost more
my 30 wire hooks up before the brake switch for fused 12v power, your red wire.
my 96 hooks up after the brake switch, same as your green wire

the connection between 30 and 87a is always on until the relay is energized (hit brakes)
so, yes. your 3rd brake wire would work for the green wire
the red wire feeds 12v to the lock up circuit, when the brakes are pushed the circuit is de-energized, releasing the lock up

[rrenner]

Hey, Hey, we got brake lights! and tail lights and turn signals! At least in the back. At first no brake lights then realized they have thier own fuse... duh. Also 12v to that third brake light wire, hooking that up to the relay for the lockup. Thanks for all the great advise on this part of the project.