1994 Chevrolet Silverado Brake Lights

  • 5.7L
  • V8
  • 4WD
  • 125,000 MILES
I am looking for a wiring diagram that shows the brake light system. The one in Haynses manual sucks. I have no brake light unless I put power hot wired to the brake switch. My 3rd brake and emergency flashers don't work either. I am also looking for a diagram of the wire block mounted on the pass. Side firewall

Any help would be appreciated.

What is an appropriate amount for a donation and where does the donation go?
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have the same problem?
Saturday, December 21st, 2013 AT 1:55 PM

1 Reply

Hi Jim; Randy here. That's the orange wire at the brake light switch that should have 12 volts all the time. That switch, and the hazard lamp system are fed from the 15 amp "stop / hazard" fuse. Check that fuse. If it's okay, check for voltage on both sides of it. In this case, a test light might be more accurate than a voltmeter. A lot of GM vehicles had aluminum wiring at the inside fuse box that was prone to corrosion and bad connections. A voltmeter might falsely pick up enough through that corrosion to say there's voltage there. A test light needs current to operate, and that current might not get through that corrosion. A voltmeter reading will be most accurate if you read it at various test points while applying the brakes.

The closest book I have is for a '93 model but GM did a real poor job in this one too. The best diagrams are from the professional web-based service manual providers. There used to be links here for Mitchell-On-Demand but I don't see them now. AllData is another popular one. This book doesn't show the block you're referring to.

As for the donations you asked about, they go to the web site owners to help pay for running the site, and they give us part of it. They also reimburse us for the 99 percent of the questions that don't include a donation. Those dollars don't come close to covering the seven computer crashes I had two years ago in one five-month period. Most of us take the time to research answers and provide information because we want people to be informed consumers and to be able to repair their own vehicles when possible.

I just got the bill for MY web site and I'm not happy. I'm spending well over $300.00 per year to dispense automotive electrical information for students and instructors, and I've never made a penny from it. Seems everyone on the internet is making money except me.

The amount of donations is totally up to you, and I and the other experts don't get to know that amount. We just know that you were kind enough to donate, and for that we thank you. You will typically not get a more in-depth answer from me if you make a donation. I spend hours each day on the computer, and some of my conversations go on for weeks. Most of the people I work with over longer time periods are trying to fix their own cars because they can't afford professional help. There's nothing in it for any of us to allow them to waste money on wrong parts and incorrect diagnoses. We can also warn them of the pitfalls of incorrect service procedures that can lead to other damage or safety issues. If someone has to go to a shop, it's easier to work with an informed and knowledgeable car owner, and simply explaining why they do some of the things they do can reduce the suspicion and mistrust of mechanics.
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Saturday, December 21st, 2013 AT 3:13 PM

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