No brake lights, cruise control doesn't work either on my 98 Chevy 2500.

[sinny87]

I have changed out brake light switch, turn signal switch, new bulbs. All my other lights work. Absolutely no brake lights nor does the cruise control work. I used a jumper wire at the relay and have brake lights but they stayed in. Any ideas? I'm at a loss.

 

[CountyLineGarage]

What year is the truck? Can you get any data with a scanner?
Otherwise grab a back probe and start chasing it back and see where you’re loosing power.

Make sure all fuses are good. Judging by the fact that you can jumper out the relay and get brake lights I’d assume that part is good. But once in a while even a full time mechanic will miss something so never hurt to double check.

If you’re getting power back to the brake lights and they kick in I’d say try and swap out the relay for starters. Being as it works via jumper I’d say that’s your best starting point.

Cruise issue may be unrelated unless it uses the same reference as your brake lights for deactivation. I’ll have a look at my chilton manual in a minute here and get back to you.

 

[CountyLineGarage]

So here’s the wiring diagram from my chilton manual along with the “key” for the symbol meanings if you’re unfamiliar . Not sure if it will give you good direction but like I said before a decent power probe will help out a good bit.

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[GoToGuy]

Always start with, Year, make and model. And eng trans if power train related. They all look the same until you open the doors and look under the hood.
If your using the relay to get brake lights, and they illuminated then the problem in the cab.
No brake lights and no cruise control, both are actuated and disconnected via the brake switch. Try checking or replacing.
We have FREE, OE service manuals in PDF format. Use search bar at top, " service manual" , look in the paragraphs , for the posting. Download your year, may be more than one volume, get all your year. Wwwwaaaayyyy better than any Haynes, Clymer, aftermarket.

Some of us have more than one truck. So always start with year, make, model, you'll get more answers.

 

[sinny87]

Thank you. I thought I had put year in. It's a 1998 Chevy 2500

 

[Orpedcrow]

Carefully check the harness from the brake pedal switch. Mine (and a few others here) have been found to rub and the metal support. It’s a real pain to see.