Late 90's GM Truck Electric Brake Plug?

I've Googled it & found some info BUT not what I need. I am looking for info or diagram/s to hook up an electric brake dash unit for my travel trailer. 1999 Chev C1500 Suburban...which is apparently the same as '98 and a few years prior. The 2000 Suburban changed as did the 1999 and up model truck? Apparently they held over the 1999 Suburban to the '98 specs. Confused yet? I am.

My Sub is a conversion model but the electrical is not affected...at least down at the fuse box. It came with a factory tow package and I figured it should have a plug already factory wired for electric brake controller but it doesn't. I know there's a bunch of these trucks still in use and somebody has to know the right way to do this. I'd prefer just buying the proper plug and match to a Tekonsha Prodigy unit but even the websites for Tekonsha & others are confusing when looking for a 1999 Suburban...seems they think the 1999 model Sub went the way of the 1999 truck changes while that apparently is not the case. Mine is similar to the '98 and earlier trucks.

Go by a camper sales place and talk to shop guys. Bet they can show and tell you exactly what you need and where it goes.

Why not just mount the controller under the dash and run the wire back to the plug under bumper. The one I had also had a brake line to attach to master cylinder

I have a 2001 GMC Sierra with towing package. Suppose to be the same. I installed an under dash controller. I watched a lot of you tube videos, must of been 50 until I found the one I needed. In the fuse panel under the hood I found a black wire with a connector with a cap on it. I removed the cap and placed the wire on #2 terminal. I had to buy a large 30 amp fuse to go in the empty slot.
I'll reply later when I check it.

Look in the fuse control center under the hood. What slots are empty? I used a large 30 amp fuse in slot #1.
A friend has almost the same truck as mine. All he had to do was apply the fuse.

Thanks Cane. I'll check that tomorrow and get back.

To check to see if it's working have someone in the truck, have a wheel on the trailer jacked up. Spin the wheel. Have person hold the brake down and spin the wheel again, shouldn't spin or have lots of drag to it. Have to use the lever on the controller to get total lock up of trailer brakes which you don't want.

Yeah I can figure that out once I get wired up. But...I was thinking there is surely a connection/plug to be made in that junction box under the dash by your left foot in the kick panel? I think I see what you're saying about installing a fuse in the box out under the hood if it don't already have one...didn't get to check it today...will try tomorrow. I recently replaced all my 4 wire flat connectors to 7" rounds on my Sub and 3 trailers I pull at diff times. It's possible I can slip under the rear with my test light and figure it out if it's already wired for it. Now that I'm thinking about it, it should already be wired and I've been trying to make this too hard.

I guess I could do what Wilbur suggested and run wires all the way from the controller but that probably won't be necessary ...specially if I can figure where to plug the controller under the junction box under the dash. Gotta be a plug that fits that junction box for my model.

This is the harness that came with my controller. It plugs into the controller and into #2 slot of the control center under the dash. No other wiring is needed in the cab. Tie the harness up out of the way.
Tekonsha Trailer Brake Control Wiring Adapter - 2 plugs, GM 3015 | eBay

Yours equipped with towing package, but doesn't have the 7 way plug already, that's weird.
From all the you tube videos I watched most said to look for a thicker blue wire in the trucks harness under the hood by the fuse center and at the rear of the truck. You'll have to add to it.
On my truck, remove the spare tire, there is a panel. It has a harness for the right lights, left lights, tag lights and the 7 way plug.
Like I said, I watched a lot of you tube videos before I found the one for my truck. Here's one to get stated with, may want to make a list so you don't watch the same ones over and over.
https://www.youtube.com/watch?v=BlI2fjOwQBU