99 Silv. Trailer Brake Controller

stolzyboy · February 25, 2008

I have a 99 silverado w/o towing package. I can't figure out where I need to connect the wiring to for the brake controller.

Here is the link to the install for the brake controller (http://www.tekonsha.com/instructions/BC%20Wiring.pdf), but I'm not sure where I get the power from/etc... Others say they have a "stud" in their fuse box where they connect to, how do I do this?

FYI, I have the trailing wiring done back to the connector for everything else (lights/etc...) but can't seem to figure out the brake controller portion.

Once I get that working, I'll get the wire back to the connector, but I'm at a loss as to what to do in the cab and under the hood.

Any help would be appreciated as I'm fully confused.

Jeremy

Q101ATFD · February 25, 2008

Do you have the 4-pin or 7-pin plug at the back of the truck? If you only have the 4-pin plug, there's a lot more work than just connecting one wire. However, if you have the 7, I think the stud you need to connect to is in the fusebox under the hood, not the one next to the driver's door. Are we talking NBS or OBS truck? I have a '98 OBS that I can look at in a day or two and let you know.

stolzyboy · February 25, 2008

I have the 7pin as I'll be pulling a travel trailer. (I installed this plug, I didn't have the OEM plug OR hitch, I installed those aftermarket)

Edit: I thought for a few seconds what NBS and OBS means... I have the new body style 99, not that classic.

Q101ATFD · February 25, 2008

This is what I could dig up. I'm not too familiar with the early NBS wiring (got a '98 and an '05). Just to humor yourself, did you look in the box to the left of the pedals for the brake controller jumper plug? Anyways, to the meat and potatoes, look at the attached image. Anyways, you are just looking for a constant +12 VDC source into the brake controller.

stolzyboy · February 25, 2008

I'll look there when I get home, there is supposed to be a panel (that's hidden and you need to take off a nut or something) and there should be a trailer "plug" there.

If there is this mystical plug, do I just get a plug from the GM that would connect to the brake controller (which has 4 wires coming out of it)?

Q101ATFD · February 25, 2008

The plug should be there regardless... GM sells a harness that has the plug in one end and the four controller wires blunt cut on the other - I think U-Haul sells the same harness for $8. However, you can order a plug from Tekonsha (part no 803025) that connects straight from the GM plug to the back of the controller. Check your local RV supply store for that. However, since you don't have the OEM towing package, there may be no wires connected to the plug. Anyways, this box is to the left of the brake pedal and is held on by a long plastic hex nut. On the reverse side of the cover "should" be a label that shows where to plug in the harness..... Keep us posted...

stolzyboy · February 25, 2008

Can I just look on the back of the plug to see if there are wires coming out? If there are, this is a good indication that using the harness will work?

If I don't have this functionality, what do I do to get this wired?

stolzyboy · February 25, 2008

I found the panel and I found where the trailer plug would go. On the panel labels, it says 6 way. I see 5 of the 6 holes have metal "prongs" sticking out of them, is that correct?

I verified I was looking at the right one by unplugging other ones, such as the courtesy lamps one.

I assume since the metal prongs are there that it's wired? If I shouldn't assume, how do I make sure they are wired (besides looking for wires as I can't seem to see up that far)?

Q101ATFD · February 25, 2008

Okay - you have the plug in place - thats a good start. It should be on the top row, second from the left.

However, the only two usable pins there now are the ones for the brake switch and the ground. The other two wires (+12V and trailer brake) are connected to the pins, but are terminated near the engine - usually under the vacuum assist near the under-hood fuse center, and are colored black (+12V) and blue (trailer brake)... The black wire needs to find its way to +12VDC, via one of the protected (I think 30A) posts in the under-hood fuse box. The blue wire should be mated to the existing brake wire that you have going back to the 7-pin plug.

stolzyboy · February 26, 2008

I don't see any posts under the fuse box. Just a bunch of fuses and a couple spots where it looks like you could thread in a bolt.

stolzyboy · February 29, 2008

Does $75 sound right for the plug from the brake controller to the fuse panel? The six prong plug?

That's what the chevy dealer here said it was, is this different than the one you can get from Tekonsha?

Q101ATFD · March 1, 2008

Heck no!

The GM cable has the 6-prong plug on one end and blunt cut on the other, and should be around $25. Find an RV shop and get the tekonsha one - it's plug and play. They might even give you some free advice if you haven't figured out where to tap into the 12 VDC yet.