Turn Signals/Hazard Warning Light/Trailer Brake Lights

I have a 2000 GMC Sierra 4WD Z71 w/heavy duty towing package and electric trailer brakes installed. I lost my turnsignals, Hazard Warning lights, and trailer brake lights at the same time. Any ideas?? I couldn't find any common fuses, but I could have just missed it.

Thanks for your help. Jim

I'd start checking the fuses under the hood, the trailer lights all have seperate fuses from the lights on the vehicle and have TRL on the fuse labels

under hood fuse block has seperate fuse for trailer brake, running, and turn, check cover for location, i think in left top area standing at fender, if fuses blown, check trailer for short

We have a 1998 GMC Sierra that we have had the same problem with twice. Both times we have had to replace the brake switch under the dash. We have ask if they make a heavy duty brake switch, since we have had to replace it twice. They don't. We were told, some of these trucks have this problem and some don't. They don't know why.