Help with Brake lights

[landarts]

I have finally finished up my long build on the Fixrupr project which is a 1972 1/2 Cheyenne truck. I replaced all of the wiring with a American Autowire kit 510089 Classic Update. Can't say enough of how great this kit is. I have all lights working except for brake lights. Tail lights work, blinkers work, just no brake lights. I have a good ground and lights are bright for blinkers and taillights, all wiring, bulbs and fixtures are brand new.

I have checked and the brake light switch under the dash is plugged in, the wire going to the proportional valve is also plugged in. What is the best way to troubleshoot this issue. Thanks!

[kazoocruiser]

I don't know how your brake switch is mounted, but on my 1981, it is made out of plastic and it mounts in a bracket that allows it to be adjusted back and forth to close the contacts when the pedal is pushed, and open the contacts when the pedal is released. It seems like maybe that might be the issue with your truck.

[Andy4639]

The brake light switch feeds from the steering column. White wire going into the switch and Orange coming out to lights. Check the white wire then the orange. As stated you will need to adjust the switch so it will activate when you step on the brakes.
Checkout the drawing and it will tell you what it is doing. self explantory really.

[Sheepdip]

Get a partner and start at the bulb socket for power both brake and tail lamp, if that fails to check out move to the wiring going to it, brake light switch etc.

Process of elimination, get the low hanging fruit before digging into the column would be my plan.

[rockyrivermark]

Chasing electric issues are a process of elimination.
Get a light 12 v tester.
Check for power going into brake switch.
The check for power out of brake switch with pedal depressed.
Then check for power at the socket, using a good ground of course.
Often it's a bad ground at the taillights but test everything.

[landarts]

Thanks for all the suggestions I will be doing some testing on Tuesday. Pretty sure it is not a ground problem at tail light since I have perfect blinkers that are bright and tail lights that are bright, just no stop lights.

[Mts67C10K20]

Had a similar problem with mine
That turned out to be the turn signal assm
After checking the obvious use the diagram provided
In the earlier post and check the turn switch
Good hunting

[VetteVet]

Originally Posted by landarts

Thanks for all the suggestions I will be doing some testing on Tuesday. Pretty sure it is not a ground problem at tail light since I have perfect blinkers that are bright and tail lights that are bright, just no stop lights.

Your assumption is correct on the rear lights.
If the lights are bright the grounds are good and the blinkers use the same wires and bulb elements that the stop lights use. So that tends to rule out the wiring to the rear lights. Stop ,tail. and blinkers. It only leaves power to the turn signal switch and the switch itself as possible problems.

If you confirm power to the switch on the white wire when the brake pedal is depressed, then the malfunction is in the switch or in the white wire from the connector to the switch. This wire powers both stoplights so it is possible that it is cut inside the column in the harness to the switch.

To troubleshoot this you can disconnect the column connector and locate the white, dark green, and yellow wires in the column half of the harness.
With a volt meter set for continuity, check for zero ohms between the white wire and the dark green wire and then the same between the white and yellow wire. This with the TS selector lever in neutral or centered position.

Power to the white brake switch wire originates at the fuse panel from the stop tail fuse. The orange wire supplies power to the dome light, the headlight switch (for the park lights, and the dash lights), and to the stop light switch.
See the diagram. Then the white wire from the stoplight switch goes to the column connector as has been described.

The voltage for the brake lights is constant and controlled by the switches so the key does not need to be on for them. VV

[JDSurge]

I have a similar problem with the brake lights except, everything worked just fine a couple of days ago but now the brake, tail, and dash lights are out. I remember when I used to drive these old trucks and cars (1960's and 70's) that when the dash lights go out it means your brake and tail lights are out also. My blinkers work just fine and the brake fuse is good.
Not sure where to start looking now. Thought sure I blew a fuse.
Any thoughts?
JDSurge

[Steeveedee]

Originally Posted by JDSurge

I have a similar problem with the brake lights except, everything worked just fine a couple of days ago but now the brake, tail, and dash lights are out. I remember when I used to drive these old trucks and cars (1960's and 70's) that when the dash lights go out it means your brake and tail lights are out also. My blinkers work just fine and the brake fuse is good.
Not sure where to start looking now. Thought sure I blew a fuse.
Any thoughts?
JDSurge

I think you should start a new thread for this, because you're going to get people answering questions from stuff that is posted above, and it will get confusing.

[JDSurge]

Good idea Steeveedee. Im kinda new to this site and wasn't sure how to start a new one but I'll read a little to find out.

[67chevemall]

I was ready to give up when I found if the turn signal arm was not centered the brake light would not work.
Then I spent 1000 bucks on a coloum and tach gauges. Sick I tell ya