Help on brake lights please

[LARRY N]

I have a 97 Silverado and the brake lights and 3rd brake light is out. I have checked the 30 amp fuse and switched the relay under the hood and the 10 amp fuse in the cab Both fuses have over 12 volts with an ohm meter. All the other lights work fine as well as the hazards. so I am guessing the brake light switch or the multi switch. I did crawl under the dash and can hear and feel the relay to what I think is the lockout for the shift lever when the brake pedal is pressed, so I'm thinking the switch itself must be ok? So to me it kinda points to the multi switch under the column. I have searched the rest of the threads on this topic and still need your input. Also if it does point to the multi switch a brief description on how to replace it.

Thanks
Larry N

[j cAT]

Originally Posted by LARRY N

I have a 97 Silverado and the brake lights and 3rd brake light is out. I have checked the 30 amp fuse and switched the relay under the hood and the 10 amp fuse in the cab Both fuses have over 12 volts with an ohm meter. All the other lights work fine as well as the hazards. so I am guessing the brake light switch or the multi switch. I did crawl under the dash and can hear and feel the relay to what I think is the lockout for the shift lever when the brake pedal is pressed, so I'm thinking the switch itself must be ok? So to me it kinda points to the multi switch under the column. I have searched the rest of the threads on this topic and still need your input. Also if it does point to the multi switch a brief description on how to replace it.

Thanks
Larry N

remove the brake pedal switch and check with a ohm meter..it could be in need of adjustment as well.

[Airjer_]

You should have power on the orange wire at the brake switch all the time. There should be power on the white wire with the pedal depressed. The 3rd brake light is independent of the turn signal switch so if you suspect the switch the only way that is possible is if the 3rd brake light is burnt out.

[kahjdh]

Prob a multi function switch, I see these alot. Find a wiring diagram and see that you have voltage coming out of the switch.

[Airjer_]

That doesn't explain the third brake light not working. Until we find out if there is power out of the brake switch and or the 3rd brake light was burnt out there is no reason to consider the turn signal switch yet.

[LARRY N]

I thank all for the responses, I took out the stop light switch and replaced it. That is a job in itself. It did fix the problem. I have a little tip on installing the retainer clip. take a scrap piece of 3/8 tubing about an inch long and insert the tubing into the keeper just enough to spread it open, then put it on the pedal assembly and gently twist sideways to remove the tubing. Worked for me!

Thanks again

Larry

[skeeter123]

I really like these forums, they save me a lot of time and enable me to dig in and repair things I would previously wouldn't try. My father told me his 1998 Silverado was very hard to get out of park into any other gear; after some troubleshooting we also found out that none of the brake lights were working. After searching this site for info, I checked the brake light relay, the wiring in the back to the brake lights, the 30-amp brake fuse under the hood and the 10-amp brake/haz fuse by the driver's door. All were OK, which pointed to the brake switch. Afte reading the posts on here about it, I laid on my back, reached up under the driver's dash where the brake pedal arm goes up to the plunger, popped the white switch up off the brake plunger, and using a small flathead screwdriver I popped the retaining clip off the side of the switch. It came out easily, but the retainer clip dropped down between the carpet and the firewall. I was able to retrieve it since the carpet isn't really glued down to anything. I pulled the switch down low enough to release the 6-wire connector, and took the switch into the kitchen. I was intending to buy another one, but it looked easy to take apart so I just popped the two halves apart. It was surprisingly simple inside; one spring (which didn't fly across the room), a plastic actuator, and three pairs of switch contacts. I couldn't really see what could go wrong, or how it could NOT work. But I took out a pair of the metal contacts, and found that where they are supposed to make contact, there was a tiny speck of dirt/carbon build-up, right on the contact pads. I borrowed an emory board (nail file) from my wife, and using the finest grit available, I sanded the contacts down to remove the build-up. I'm talking about a speck that's maybe 1/32" or smaller. The three pairs of contacts are arranged so that one pair "closes" when the brake is applied, the other two "open" when the brake is applied. The one that "closes" had the biggest speck of build-up on it; this was the one connected to the orange and white wires. I cleaned all the contacts up, re-assembled the switch, and re-installed it. I did end up holding a flashlight in my mouth, but the process wasn't that bad. Stepped on the pedal, Brakes Lights Work! Comes out of park just fine. I haven't verified if pressing the brake will turn off the cruise control yet, but I'm confident that it will.
If all three of your brake lights aren't working, or if you can't get it out of Park, try cleaning the contacts in the brake switch.
Hope this helps.