HELP!!! no brake lights

I have a 99 suburban. The other day I was towing my trailer to pick up a car. When I hooked the trailer up I checked all the lights on the truck and trailer. Every thing was good. When I got home I was backing in the trailer and my brother noticed I had no brake lights in the truck and trailer. First thing I thought was bulbs. Nope not that. Then I thought brake switch on pedal. Nope not that:grinno: . OK lets get the test light out. juice in and out of the switch but nothing at the back of the truck. Then it clicked, chek the fuse and or relay. So I open the hood take the top off the fuse box, look at the top to see what fuse and relay are for the stop lights. Sure enough they were on the lable but to my suprise there were nothing in there slots.:screwy: Thats right no relay or fuse where they should be nothing. What the F. HELP!!! It does have a factory tow package. Would there be another spot where the relay and fuse would be?? :banghead:

Look for fuses in the passenger compartment.

Im no mechanic but the brake lights went out in the back of my 99' Suburban and it turned out to be the Multi Function Switch in the steering column. This was a while back and the dealer fixed it for free, out of warranty.

Fuse no. 1 a 20 amp in the inside IP panel fuse box
If the brake light switch has 12 volts in and out the fuse is good.
Check for brake light in and out of turn signal switch?
Does turn signals work ok?

Also with a trailer plug check trailer plug wiring and where it connects to main truck wires.
Are you getting brake light/turn signal voltage to rear of truck?

Where is the ip panel located? I have juice to the turn signals but nothing for the brake. It has to be something stupid. I tried to get a wiring diagram from the local chevy dealer but hey said they had nothing for it.

Open drivers door and look on right side/end of the dash.
There will be A little door that lets you into fuses.

Does brake light go into and out of turn signal switch.
Does turn signals work?

This info is for the Old Body Style only. If your Sub is New Body Style it has different systems. So, with that in mind:

The brake lamp relay in the underhood fuse block is only used on pickups, not on Subs or Tahoes. The I/P fuse block is on the left of the panel. You can see it when the drivers door is open.

If your Sub has the 3rd brake light and it is working ok, the fuse and brake sw are good. If your rear turn signals are working ok then the wiring and bulbs are good as the turn signals and brake lights use the same bulbs and wiring from the turn signal sw.

Hey MT-2500

I did check those fuses also. But when I looked in the box I did not see the top row of fuses. :banghead: This time I took a closer look and sure enough that was it. Thanks!! I do have another one seeing you got this one. I had the suburban for 3 years now. From the first day I had it when the key is off the blower motor (heater) will come on for a few seconds then stop. Maybe an hour will go bye and then it goes on again for a few seconds. This happens all day long. Just for 2-3 seconds each time. Good thing for dual battries. Never really checked it out. I just live with it.

Look and see if someone has wired in an afterblow module into your blower motor- they use these sometimes in humid climates to dry out the evaporator- to keep bacteria from growing- it has an algorithm and decides to run th eblower at various intervals depending on shut down temp, engine on time, etc...- it would be wired in somewhere near the blower motor- to feed it....

Silly, but it could happen. I bought a used 97 silverado. The guy swore it never towed anything. Couple nights later a car pulls me over. My previously working tail lights were dead. I was close to home so I drove on.
Next morning inspection revealed a dangling ground wire and evidence that a tow hitch had been recently removed. The loose bolt vibrated free and my lights went out. Easy fix, I got a bolt and replaced it in the frame and hooked up the dangling ground wire back to the frame. Ta-Da! Tail lights, but I din't check the brake lights. Next night, guy tells me I got no brake lights, tail lights yes. Got a flashlight and looked and amazingly, a second ground wire kind of "curled up" into the frame when that previous bolt popped out. Re-connected it and all my lights worked. Just do a simple double check, maybe this will help!

JMR

My 94 lost all lights but headlights. Kept blowing fuses as soon as I hit the switch. turned out to be the wires back at the trailer light hookup. wire hat come aprt from the crimp and was shorting out.