99 Suburban dash lights

When I put my foot on the break without keys in the ignition the dash lights come with a buzzing noise. While driving when I step on the break the signal light stops blinking until I take my foot off the break. I replace the Flasher and checked all fuses. Any thoughts?

When I put my foot on the break without keys in the ignition the dash lights come with a buzzing noise. While driving when I step on the break the signal light stops blinking until I take my foot off the break. I replace the Flasher and checked all fuses. Any thoughts?

Turn signal switch possibly, that might explain the brake / turn signal part of it, as those two circuits interact, and the switch is the most likely source of a problem......but not sure about that dash light problem.
Sounds like a trip to the dealer maybe. Good luck.

Here is a couple of ideas that could be causing the problem.The brake lite circuit may have a bad ground and is grounding through the park circuit.The other suggestion is that the fillament in one of the bulbs from the park lite circuit is touching the brake lite fillament,thus suppling power to the park curcuit.Does any of the park lites come on when the brake lites are on,or is it just the dash lites?Poor grounds can cause lots of electrical problems.I would check all of these.
chuck's

okay heres whats happening. the brake light circuit is feeding power back into the parklight circuit. i'm willing to bet a beer all the parklights come on when the brakes are on as chuck mentioned. first off do you have trailer wiring??? this is the most common place where wires short out because they get beat up by rocks and mud. if you don't have trailer wiring remove the tail light assembly's and unplug them. if the problem is gone it's one of the light socket boards. another place where wires corrode on chevy's in the wires under the carpet near the drivers door. it can take a lot of time to find electrical shorts but if you get a diagram(chiltons/haynes) and go after the places where the park light& brake circuit are common it helps narrow it down a bit. also what happens when the park lights are on? do any of the brake lights light up? a little off topic but one time i had a truck with a manual transmission that would keep running after removing the key if it was in reverse while the brake was pressed. it would shut off as soon as the brake was released. what was happening was power from the brake circuit was feeding through the reverse circuit all the way back to the ignition switch.
happy hunting?

I pulled the trailer lights off and pulled the fuse to the rear tail lights. the dash lights and break lights still go on. I never check for the parking lights. I took the truck to the local mechanic and he tried to replace a switch in the steering column but no luck. Thanks for the help I will let you know what we find.

take it to another mechanic. he should've known better than to change the multi-function switch because the park lights have nothing to do with that switch. try pulling the fuse for the highmount brake light. does your cruise control work? i bet it won't if the park lights are turned on.

Sure enough it was the trailer lights. I bought the truck used and the trailer lights were not using the towing package lights. They tapped into the regular lights. I only pulled the connector but the mechanic pulled the entire splicing and it resolved the problem. Thanks again for you help.