Tips on installing a Brake Controller in a OBS (1999 Suburban)

BiigBird said:

I googled installing a brake controller on my 1999 OBS Chevy Suburban. Most answers left somethings unclear. Here is what I did and I think will help you find a straight forward install.

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This photo shows where I SAFELY drilled thru the firewall

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First photo shows the wire going thru, second photo shows hole placement. I did cut back a small amount of the plastic and insulation as shown in photos.

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These are 2 types of grommet. I found the plastic grommet much easier to instal, works equally well and available at hardware stores.

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This shows the wire used to turn on your brake lights when you MANUALLY use the brake controller. The wire I used is in the center, be sure and use a test light to be sure this will work for you.
The hot wire can be connected to the fuse box HOT INPUT under the hood and I used a wiper motor screw for the ground. AGAIN, check everything with a test light. It took me quite awhile to install the controller I think these tips will cut down install time immensely.

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jhornsby3 said:

My controller was just plugged into the box under the dash in my 1998 Burb. There was a harness that was plugged into the harness from the controller and was from Curt that plugged into the box. When I got my newer pick up, I had to get the harness from the controller to the new vehicle under dash box.

Might be worth checking for the prewired connection. Not sure if mine had the tow package or not.

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Hipster said:

I thought by 99 most were pre-wired plug and play with adapter harness. Just need to locate plug.

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jhornsby3 said:

My controller was just plugged into the box under the dash in my 1998 Burb. There was a harness that was plugged into the harness from the controller and was from Curt that plugged into the box. When I got my newer pick up, I had to get the harness from the controller to the new vehicle under dash box.

Might be worth checking for the prewired connection. Not sure if mine had the tow package or not.

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A97obs said:

Show me this location and pre wired plug harness from GM wired up Under dash from any 92-99 Obs as a visual illustration ?

As stated they offer and put in place the Orange and blue wires tucked under the brake booster taped up if you have a tow package from the get go .. but they require hardwiring the blue wire into the brake controller and the orange wire at the fuse block +

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A97obs said:

From what I understand you have to hardwire a 99’ at least
Yes the Orange and Blue wires are pre positioned taped under the brake booster . Cut the tape pull the wires down and run the orange to the Fuse block . My orange wire had a Ring Terminal already in place .
The same wires are already ran down the frame and tucked away at the Hitch.
As far as a hidden harness that plugs and plays in a 97 98 99 etc I don’t think it exists under the dash . And that would mean the modern day curt brake controller plugs would have to be the same as a 25-30 year old plug and play harness that’s under the dash in a OBS.

I know the two wires exist if you have a tow package on a 92-99 etc but as far as a harness that’s hidden that’s already pre wired nah…

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A97obs said:

I wasn’t aware they (GM) gave a curt brake controller right off the car lot or right off the assembly line in any Obs in the 90s that’s probably where I’m misunderstanding? Maybe that was a k1500 thing or 4wd models

I just know on a 2wd for sure the wires are already ran from the factory to hardwire one in if you have a hitch from the factory usually and they’re visible as Orange and blue under the brake booster at least for a suburban maybe the same for a c1500 Silverado of the era

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