Posted 2008-02-16 8:56 PM (#77008) Subject: Brake controller setup on a 99 suburban
Member
Posts: 10
Hi all! My other half is a horse girl but I'm new to this stuff. We've recently purchased a 99 Suburban (old body style, GMT400, same as the 1998 model) and I'm doing my part by trying to get the brake controller set up. This is the model before GM started including a brake controller harness connector under the dash. Here's what I understand so far with respect to the wiring:
The controller (a Tekonsha Prodigy) has 4 lines coming out of it: black, red, white, and blue.
The 7 pin socket the trailer will plug into has a plug for the built-in 4 wire light connector (left/right turn signals, tail lights, and ground), in addition to a black wire, a blue wire, and an orange wire.
As far as I can tell, this is what I have to connect:
- Black wire on the controller goes to a stud coming out of the underhood fuse block (fused for 30 amps).
- Red wire on the controller splices in on the ground side of the brake light switch on the pedal.
- White wire on the controller connects to ground.
- Blue wire on the controller connects to blue wire on the 7 pin socket.
- Orange wire from the 7 pin socket goes to another stud coming out of the fuse box, for auxiliary electronics on the trailer.
Assuming the foregoing is correct (?) I had a few questions:
1) Where should I get ground for the white wire on the controller? Do I have to run a line from the battery or chassis or can I just splice into an existing ground wire under the dash?
2) This leaves me with a black wire going into the 7 pin socket that I don't know what to do with. What's this line for and what should I connect it to?
Sorry for the long post, but I'm thoroughly confused!
Posted 2008-02-17 8:08 AM (#77028 - in reply to #77008) Subject: RE: Brake controller setup on a 99 suburban
Veteran
Posts: 296 Location: Tennessee
Your connections look right to me.
For the white ground wire, you can splice into an existing ground wire, but I would just find a screw or fastener that attaches into the body sheet metal and attach your wire there.
On most 7 way plugs, the black wire is the 12v fused battery lead for charging the breakaway battery, powering interior lights, etc..
Posted 2008-02-17 11:24 AM (#77051 - in reply to #77028) Subject: RE: Brake controller setup on a 99 suburban
Member
Posts: 10
On most 7 way plugs, the black wire is the 12v fused battery lead for charging the breakaway battery, powering interior lights, etc..
I thought that's what the orange Aux line was for. It's possible the terminology is just getting mixed up here. In short though the truck comes with two fused lines going to the rear, one for brakes and one for aux. Am I going to have to run a third line?
Posted 2008-02-17 12:33 PM (#77054 - in reply to #77051) Subject: RE: Brake controller setup on a 99 suburban
Expert
Posts: 1416 Location: sc
Originally written by rationull on 2008-02-17 12:24 PM
On most 7 way plugs, the black wire is the 12v fused battery lead for charging the breakaway battery, powering interior lights, etc..
I thought that's what the orange Aux line was for. It's possible the terminology is just getting mixed up here. In short though the truck comes with two fused lines going to the rear, one for brakes and one for aux. Am I going to have to run a third line?
The 2 fused lines going to the rear are for the trailer brakes and the 12 volt power....usually blue and black. The orange/AUX wire is probably for the backup lights. Yes you need to run a ground wire for the brake controller directly to the battery. I belive that is specifically addressed in the Prodigy instructions. The 7 pin socket should be grounded to the frame.
Posted 2008-02-17 12:59 PM (#77057 - in reply to #77054) Subject: RE: Brake controller setup on a 99 suburban
Member
Posts: 10
Thanks! I had seen that page before with the plug/socket diagrams, but was confused in part because of the unfortunate coloring of the heavy wires already in place on the truck (the orange wire is intended for the black 12v connection on the diagram, not the orange Aux connection).
I hadn't seen a reference in the Prodigy docs to connect the unit's ground to the battery but will look again. Sounds like a good idea though, I can solder it to the terminal, unless there's an easier way.
Now to find a way to tap into the brake switch line -- which I can't see because of a steering column bracket!
Posted 2008-02-17 5:00 PM (#77086 - in reply to #77008) Subject: RE: Brake controller setup on a 99 suburban
Veteran
Posts: 296 Location: Tennessee
Rationull, the Prodigy wiring instructions say "The WHITE wire must be connected to a suitable ground location. The negative terminal of the battery is a suitable ground location in the absence of a Trailer Tow Package connection."
Of course, the battery is not the only suitable ground location. Any point that returns the full amperage is "suitable."
Posted 2008-02-17 5:22 PM (#77088 - in reply to #77086) Subject: RE: Brake controller setup on a 99 suburban
Expert
Posts: 1416 Location: sc
Originally written by Towfoo on 2008-02-17 6:00 PM
Rationull, the Prodigy wiring instructions say "The WHITE wire must be connected to a suitable ground location. The negative terminal of the battery is a suitable ground location in the absence of a Trailer Tow Package connection." Of course, the battery is not the only suitable ground location. Any point that returns the full amperage is "suitable."
True, the battery is not the only ground point that will "work". However the Prodigy is very testy about grounds, be it at the trailer plug or the controller itself. Trust me I know. I would not waste my time grounding anywhere other than the battery.......will likely save time in the long run.
Posted 2008-02-17 8:05 PM (#77107 - in reply to #77088) Subject: RE: Brake controller setup on a 99 suburban
Member
Posts: 10
Thanks for the info. I'll definitely ground to the battery, then. At this point I think the hardest thing will be finding the wire I need off the brake light switch.
Posted 2008-02-17 8:50 PM (#77116 - in reply to #77008) Subject: RE: Brake controller setup on a 99 suburban
Regular
Posts: 97 Location: Newport News, VA
My husband is currently in the middle(well, not quite the middle, yet) of the same process on my 95 Dodge Ram 1500. So far, he mounted the unit under the dash and got the circuit breaker. The truck already had a receiver hitch and a round 6 pin plug for a hitch. I don't know it's history is as far as what it was ever used to tow. I recently purchased this vehicle and under the dash, just to the right of the steering, there is a plastic plug. I thought, "Excellent, it is already wired to plug in a break controller." I bought the Dodge plug(it did say 96 and newer and the guy I bought it from said he didn't think they came with them any earlier than 96) and it doesn't fit. Any idea what the plug under my dashboard might be for? Also, it does have the lovely 6 pin plug in, however, the trailer I bought has a 7 blade plug. Which is the best to change, the truck or the trailer? I bought an adapter, but when I tried it, the marker lights don't seem to be coming on and when you use the turn signal, both lights flash. Since both things are new to me, I don't know if the problem is the truck, the trailer, or the adapter. I am going to try to get someone with a 6 pin trailer let me plug the truck in and try it and see if someone with a 7 blade vehicle will test my trailer lights. Man, this trailering stuff is HARD!
Posted 2008-02-17 9:17 PM (#77121 - in reply to #77107) Subject: RE: Brake controller setup on a 99 suburban
Expert
Posts: 1416 Location: sc
Originally written by rationull on 2008-02-17 9:05 PM
Thanks for the info. I'll definitely ground to the battery, then. At this point I think the hardest thing will be finding the wire I need off the brake light switch.
IIRC, look for a spade terminal marked NAT or somthing similar on the fuse panel/box under the steering wheel. Check it with your tester.
Posted 2008-02-17 9:39 PM (#77124 - in reply to #77116) Subject: RE: Brake controller setup on a 99 suburban
Expert
Posts: 5870 Location: western PA
Originally written by luckeys71 on 2008-02-17 9:50 PM
Also, it does have the lovely 6 pin plug in, however, the trailer I bought has a 7 blade plug. Which is the best to change, the truck or the trailer? I bought an adapter, but when I tried it, the marker lights don't seem to be coming on and when you use the turn signal, both lights flash. Since both things are new to me, I don't know if the problem is the truck, the trailer, or the adapter.
Get rid of the adapter and buy either a 6 or 7 pin plug/receptacle and wire the trailer/truck correctly. I use a 7 pin plug in my truck and trailers. In my area it seems to be used more often than the 6 pin plugs. I only use 6 wires, omitting the back up light circuit.
Posted 2008-02-18 11:21 PM (#77226 - in reply to #77121) Subject: RE: Brake controller setup on a 99 suburban
Member
Posts: 10
Originally written by chadsalt on 2008-02-17 7:17 PM
IIRC, look for a spade terminal marked NAT or somthing similar on the fuse panel/box under the steering wheel. Check it with your tester.
You're a lifesaver! There are two spade terminals in a socket labeled NAT just as you say. They get 12 volts when I tap the brake pedal.
Brake controller setup on a 99 suburban
