The Stovebolt Site Forums The Shop Area The Electrical Bay Brake Light Issue w/Speedway Harness

I installed a 22 circuit Speedway wire harness even though I am not planning to use a lot of those circuits currently. I have a lot of the fuses pulled but beleive I have all the circuits powered that I will need for now.

I am finally getting to the point of wiring lights and find that while the parking lights and turn signals all work the brake lights do not. I have confirmed that I have 12volts at the brake light switch and 12 volts on the other terminal of the brake light switch when the pedal is depressed.

I am not sure where the harness connects the brake light function into the rear turn signal function and suspect that is where I need to fix the issue.

Anyone here have insight into this harness (I realize it is not original so a limited population or members) that can help point me in the right direction would be appreciated.

I don't know the harness, but don't forget that the brake light circuit goes thru the turn signal switch.

The output side of the brake light switch connects to pin 17A (grey) of the turn signal (column) harness.

Power for the brake lights passes through the turn signal switch so it can make them flash.

What kind of turn signal switch do you have? I suspect there is a misalignment between what wiring it is expecting and what the harness is set up for.

I talked to Speedway tech support and concluded the problem is in my turn signal switch. I have confirmed that power through the brake light switch is being delivered to the turn signal switch so next step is to take the switch apart to see if I can fix it. It is a new to me, appears to be not previously used column mounted switch that I got from a fellow Bolter.

I should have realized the turn signal switch is where the turn and brake light circuits must intersect but didn't until clued in by the Speedway tech support person.

Depending on the type of turn signal switch, some modifications might be necessary to make it work in the modern way.

What kind of switch is it?

WICruiser PLEASE tell us the brand and model number of your turn signal switch so we can help you. We are as good or better than Speedway customer support, What they know they got from reading STOVEBOLT. You were already "clued in" by Bill Hanlon and FIB in 90 minutes with then havnig VERY little info. They, and we all, are gearing up to help ASAP.
Let us know if you want us to help you.
It's just a minor miswire. Go over the instructions a few more times and be cognizant of wire color or function of T/S switch.
Did you build/wire the T/S mating connector half? Can we see some good pics of that to check the wiring with a new set of eyes. We can download the instructions very easily ourselves.

The switch instructions say it is from Foxton. It attaches to the column with a hose clamp. I tried to upload a picture of the wiring diagram but I'm experiencing some technical issues with the website preventing that at the moment.

I have taken the switch apart and confirmed that there is power to the "brake" wire and contact when the brake pedal is depressed. Internally the brake wire connection makes contact with a metal strip that crosses over to the other side (presumably to contact with the second brake/turn light wire).

I confirmed that if I touch the brake contact with the right rear turn signal wire contact and depress the brake pedal that the light illuminates, but the internal contacts are apparently not functioning as intended.

There are 3 metal contact strips supported by small spings in a plastic case that rotates with the switch lever relative to the fixed plastic plate that has the wires connected to contacts. I presume that in the center position the brake contact is intended to be connected to the left and right rear turn signal wires such that when power is provided through the brake switch that the lights both illuminate. when the switch is moved to the right or left turn position the contact plates connect the switches power source with the corresponding rear turn signal wire through the flasher to illuminate/flash the corresponding rear light. I supect that the other "brake" light would be illuminated even though the contact position is rotated from the center position.

I have tried to clean the contact plates to remove any residue from sitting on a shelf for an unknown amount of time but so far no joy. I have not tried to clean the fixed contacts yet but that is probably the next step.

Assembly of the switch requires some adjustment of the screw that secures the rotating part to the fixed part such that they can rotate relative to each other but still retain contact pressure between the metal strips and the fixed contacts. The springs pushing the plates against the contacts are not very strong and do not have a lot of excess compression to maintain contact between the plates and the fixed contacts.

Understand you are doing your best. No problem.
I was looking for markings on the switch body to indicate brand and model. They are ususally marked.

I Can't troubleshoot the guts of your switch. You are doing what I would do. testing., cleaning, observing operation to detect what is wrong. If anything

Is 6 or 7 wires coming out of the T/S switch or 4 or ?

The brake portion of the T/S switch function is to turn off the brake light signal to the bulb in the direction of turn. Otherwise it would not flash.

Yes Stovebolt had been slow earlier.
Keep trying "attachment manager" to post pix of T/S switch, it's instructions and the connector you "built".
It's too bad you took it apart before we got a chance to suggest tests. This can cause the dreaded two different issues at once and us not being able to record a boiler plate.

You said all turn signals work but not the brake lights. That sounds like a very easy problem to fix. It means bulbs are all good, flasher is good and T/S switch is routing signal pretty good. Grounds are good.
Typically you will have 7 wires in and out of the T/S switch:
1. From brake switch output
2. To RF brake/turn filament
3. To LF brake/turn filament
4. To RR brake/turn filament
5. To LR brake/turn filament
6. From flasher La vintage vehicle to
7. From flasher P

This is the list for older aftermarket clamp-on switches without 4 way and with P, L and X flasher terminals. Variations will apply. As well as the 8th BLK wire for horn. You don't need to use it , you can wire the horn separate if that is better for a 1949/50. All part of adapting a modern pre wired universal harness to a vintage vehicle.

As you know the running/parking lights front and rear are on a different bulb filament and are controlled by the headlight switch. You need dual filament bulbs.

There is a mistake on the list of pinouts in the instructions. Anyway, be sure you have the Speedway wires plugging into the appropriate wire/function on the T/S switch that they call for. Don't rely on old T/S switch wire colors.

14A & B H Light Blue Left Front Turn Feeds the left front turn lamp bulb high filament and the right left turn dash indicator lamp

Thank you for the feedback and additional information.

There are 7 wires coming ot of the TS switch. I was able to upload the wiring diagram (see attached). All the lights (front and rear) are new dual element bulb types (no LEDs). The parking lights all illuminated correctly with my headlight switch in the first detent.

The #7 yellow wire is not connected, the flasher is integrated into the fuse block.

I will get a picture of the connector where the TS switch and harness meet to add some insight.

It sounds like my understanding of the brake light switch interaction with the TS switch is off in that the movement of the TS switch breaks the connection between the brake switch provided power and the flasher provided power to the appropriate rear light. That being said I think my problem remains that the power getting into the TC switch from the brake light is not being connected internally to the rear lights.

Here is a picture of the harness connection between the TS switch and the main harness.

I have been able to get one brake light to work sometimes but nothing consistent regardless of what I try within the switch internals.

The brake light that never works still does work with the TS switch in the appropriate position so I am stumped.

Given the other items on my to-do list for the truck I will continue to play with the TS switch but at the same time move on to other items on my list. At some point I will need to decide if this switch is viable or if I should just move on to a new one. If there are recommendations regarding a preferred source/manufacturer's switch it would be appreciated in case I decide to go that route.

Everything looks good except the bottom connection in your pic. Black wire from T/S to harness black wire? The harness connector black is horn, where is that black wire going on the T/S connector you built ?

Also on the T/S switch wiring diagram is the left rear a Green wire? Can see for sure.

I believe the left rear color is Cyan which appears green in my connector picture. I can confirm which wire that connects in the main harness.

The bottom connection in my connector picture is not from the TS switch and is the horn wire that comes from the steering column going to the horn relay.

The black wire coming from the TS switch is second from the top in the picture. I can confirm which wire in the harness it connects with but it should be the right rear turn/brake light.

All connections are OK that I see. If the horn works then that is good.
Bottom line:
Only 6 wires used from T/S switch. No. 7 (P) not used.

Cyan is NOT green. There is a sky blue on the diagram that can be called Cyan. There is no green on the T/S wiring diagram.
It is possible that they saw that sky blue is very close to Cyan and changed it to green but not the diagram. HOWEVER... cyan has never been available as an automotive or military wire color. So they never had a cyan wire. The standard in the T/S and automotive world is Lt Blu and Dk blu. There was never a sky blu or cyan. The company made up the names.

If you are sure that wiring is all correct after all posts here, I highly recommend to get away from that old T/S switch.
We have to know that the switch is good to continue. You have said all lights flash when lever is shifted left or right. That almost covers all of the issues there might be with wiring or switch or grounds or bulbs. You tested the brake switch and it operates as designed. All that is wrong according to what I read is the brake lights don't work.
So if there are no miswires.......Right now, as you have reasoned, it seems like a problem with the brake "circuit" inside T/S switch. Starting with a known good switch is the answer.

Bartamos, thank you for sticking with me through this.

I finally went back and checked all my wiring from the TS switch and discovered that I screwed up and followed the original TS switch wiring that was identified previosuly here as being in error. Once I switched the #3 and #4 wires things got better. It still took some effort on my part to get the TS switch back together with enough, but not too much contact pressure but everything is working now.

The bottom line is I should have been paying more attention to the original feedback that highlighted the known wiring diagram error. I thought because the turn signals all worked the wiring had to be correct but because the front and rear were wired wrong they worked okay with the turn signal (both flashing) but not with the brake.

The attached connector shot shows the updated wiring locations with #3 and #4 swapped.

I don't see that you have done a correction. It seems you have done a miswire now. What is the known wiring diagram error you speak of. please explain.

But I can't argue with........ "but everything is working now."

I was referring to the previous note that reads "There is a mistake on the list of pinouts in the instructions. Anyway, be sure you have the Speedway wires plugging into the appropriate wire/function on the T/S switch that they call for. Don't rely on old T/S switch wire colors." What I had previously was the #3 dark blue and #4 green wires going to the left front and left rear respectively. I have swapped those 2 such that the dark blue goes to the left rear and the green goes to the left front.

The wiring now aligns with the information that I received from Speedway regarding which wires from the TS switch align with which wires in the Speeday harness.

OK, if it works now, good job.
Very glad that somehow it generated a fix. Good work hanging in there.
Let us know if new issues show up.