Jump to content

How-To: Install Electric Trailer Brake Controller GMT900.

SinisterSS

Recommended Posts

vette1028 New Member

vette1028

Posted
Posted

JUST BOUGHT A 2009 DENALI PICKUP. IT HAS THE TRAILERING PKG, BUT DOES NOT HAVE THE FACTORY BRAKE CONTROL SWITCH IN THE LWR DASH. DOES ANYONE KNOW IF THE TRUCK IS PREWIRED FOR THE FACTORY SWITCH. I CAN BUY THE SWITCH & LWR DASH PANEL FROM GM BUT NOT SURE IF ANYTHING ELSE IS NEEDED.

  • Replies 39
  • Created
  • Last Reply
brims Senior Enthusiast

brims

Posted
Posted

It's been tried, there are a LOT of components that are needed. I forget who was going to do it but he gave up seeing how much stuff was needed to add it, plus they don't seem to sell those parts to install the controller after it's been built at the factory, liability or something.

  • 2 months later...
ub2slo Enthusiast

ub2slo

Posted
Posted

Problem, I just installed my brake controller and added the 7 way plug in the bed. When plugged up to the camper the reverse lights come on and stay on. All functions work, tail lights, blinkers, hazards, and brake lights. Anyone have an idea of what could be wrong?

 

Thanks

  • 2 months later...
  • 1 month later...
MattyB4x4 Enthusiast

MattyB4x4

Posted
Posted
the step by step directions are not working.....

 

I just noticed that too. Any way I could get them?

 

Have a trip on Friday and got the controller yesterday.

 

Thanks!

MattyB4x4 Enthusiast

MattyB4x4

Posted
Posted
Here ya go. I happened to save them.

 

GMT900 Prodigy Install Info

 

Its a PDF, so you will need acrobat reader. It is big, so it takes a few seconds to load.

 

C

 

Thank you so so much!!!! I'm working in the dark in my driveway right now. Got everything taken care of but need to run to the hardware store...didn't know what size nuts to get for the two posts on the fuse box.

compulynx Enthusiast

compulynx

Posted
Posted
Problem, I just installed my brake controller and added the 7 way plug in the bed. When plugged up to the camper the reverse lights come on and stay on. All functions work, tail lights, blinkers, hazards, and brake lights. Anyone have an idea of what could be wrong?

 

Thanks

 

Sounds like you got the +12v on the trailer hooked to the center pin. Should be pin 4. Center Pin on a 7 wire is for backup lights on a GMT900. It is labeled "auxillary in this diagram.

 

con3.jpg

 

Just for info, you are looking at the trailer plug from the back, not looking in to it. This is where these diagrams throw a lot of folks....and this is the plug on the trailer, NOT the truck receptacle.

 

This would also be the wiring pattern looking INTO the receptacle on the truck.

 

con2.jpg

 

C

MattyB4x4 Enthusiast

MattyB4x4

Posted
Posted
Here ya go. I happened to save them.

 

GMT900 Prodigy Install Info

 

Its a PDF, so you will need acrobat reader. It is big, so it takes a few seconds to load.

 

C

 

Thank you so so much!!!! I'm working in the dark in my driveway right now. Got everything taken care of but need to run to the hardware store...didn't know what size nuts to get for the two posts on the fuse box.

 

 

 

Got it all hooked up, minus the fuse. Does it make sense that I would have power at the controller without the fuse in? I assume that the fuse has to do with the actual trailer brakes and not the brake controller itself?

 

Thanks again

  • 4 months later...
gerry001 New Member

gerry001

Posted
Posted

Yet another thanks. That was one of the best instruction/info packages that I've seen anywhere. I also liked your mounting approach. A little more work here, as all I could get was steel, but painted to match and it looks good.

  • 3 weeks later...
  • 2 months later...
Jsdirt Senior Enthusiast

Jsdirt

Posted
Posted

I just installed the P3 in my '07 NBS Silverado. On the white wire there's a tag -- it says to connect DIRECTLY to battery ground, or it will result in intermittent operation. I can attest to this. While towing an 18' flatbed with an S10 Blazer on board through hilly backroads , I got full lockup on some applications of the brake, then other times not enough braking. Got real annoying in NY traffic. Light pressure on the pedal would result in violent see-saw action of the truck & trailer on occasion. Didn't happen every time, but enough to be aggravating.

 

Going to see if I can get a wire out there without drilling through the firewall, but more than likely I'll have to drill. Hopefully that will take care of that issue - which I'm thinking it will due to the number of times this is mentioned in the installation instructions, along with the ground wire sticker.

  • 1 month later...
ponchjoe Enthusiast

ponchjoe

Posted
Posted
I just installed the P3 in my '07 NBS Silverado. On the white wire there's a tag -- it says to connect DIRECTLY to battery ground, or it will result in intermittent operation. I can attest to this. While towing an 18' flatbed with an S10 Blazer on board through hilly backroads , I got full lockup on some applications of the brake, then other times not enough braking. Got real annoying in NY traffic. Light pressure on the pedal would result in violent see-saw action of the truck & trailer on occasion. Didn't happen every time, but enough to be aggravating.

 

Going to see if I can get a wire out there without drilling through the firewall, but more than likely I'll have to drill. Hopefully that will take care of that issue - which I'm thinking it will due to the number of times this is mentioned in the installation instructions, along with the ground wire sticker.

 

How did this turn out? I can't find a black wire in the factory harness. Do you have to run a seperate ground?

 

Thanks,

Joe

Doug_Scott Senior Enthusiast

Doug_Scott

Posted
Posted
I just installed the P3 in my '07 NBS Silverado. On the white wire there's a tag -- it says to connect DIRECTLY to battery ground, or it will result in intermittent operation. I can attest to this. While towing an 18' flatbed with an S10 Blazer on board through hilly backroads , I got full lockup on some applications of the brake, then other times not enough braking. Got real annoying in NY traffic. Light pressure on the pedal would result in violent see-saw action of the truck & trailer on occasion. Didn't happen every time, but enough to be aggravating.

 

Going to see if I can get a wire out there without drilling through the firewall, but more than likely I'll have to drill. Hopefully that will take care of that issue - which I'm thinking it will due to the number of times this is mentioned in the installation instructions, along with the ground wire sticker.

 

If there is a wire from the neg term on the battery to the body, then there is no reason the run a dedicated wire to the battery. About the only issue that can come from that is the wire may not be big enough to support all the grounds needed. If you want to make sure it is big enough, simply run a 10 gauge wire from the engine to the master cyl mount (to avoid having to scrape paint off of the body to ensure good connection)

  • 4 weeks later...

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Latest Articles

  • Posts

    • 81mmcat
      Higher oil pressure after DFM shut off

      By 81mmcat · Posted

      Can anyone explain why the oil pressure runs higher after the DFM is shut off?  just installed the Pulsar Lt.
    • fm2176
      New to Me 2010 SLE (Quirks, Issues)

      By fm2176 · Posted

      Thanks!  I figured as such; GM and other manufacturers have used standard parts and harnesses across trim levels and such for decades.  I pulled the blank accessory cover off of my commuter van (a 2016 or so Chevy 15-passenger) years ago and found the plug for a USB outlet.  It wasn't connected to anything, though (I tried swapping in an outlet from another van).  I was a GM Tech years ago (late-90s) and was pretty familiar with my 2006.  I might be wrong, but I view newer vehicles (pretty much anything made in the past 20 years) as being a lot more plug and play.  Meaning, more unused wires and plugs unless you have the Mack Daddy of vehicles.    
    • Coastie05
      It's Been a Long Time...

      By Coastie05 · Posted

      Welcome back!
    • davester
      New to Me 2010 SLE (Quirks, Issues)

      By davester · Posted

      not all plugs will be used.  gm uses more generic harnesses that support most/all options, and if your truck doesn't have a specfiic option, the plug won't be used (commonly will have a dummy insert in the plug , or it'll be taped up, but some may just be left as is).  But it's sldo possible some p.o. has installed the wrong/cheaper parts that aren't correct for your vehicle...
    • fm2176
      New to Me 2010 SLE (Quirks, Issues)

      By fm2176 · Posted

      First off, I'm not trying to just get easy advice/fixes for the issues I've noticed so far.  I'll be combing through the site via searches and such, and if past experiences are any indication, should find what I need.  For the sake of conversation, though, I figured I'd post the handful of things I've noticed in the 12 hours since buying my 2010 SLE CCSB.     Indicator lights: Airbag and TPMS.  The tire pressures aren't reading for any of the wheels, so I'm pretty certain the sensors were either removed, are damaged, or are otherwise inoperable.  I used to mount and balance tires 25 years ago but am pretty much ignorant when it comes to TPMS.  My 2006 didn't have the sensors and this might be the fourth vehicle I've owned that does.     Radio: Rear speakers aren't working.  I removed the driver's side rear door panel and checked the speaker and wiring.  I also removed the sill and b-pillar covers to check the wiring.  A few minutes of Google Fu showed that this is potentially a head unit issue.    Switches: Power mirrors don't turn left/right.  I ordered replacement driver's door switches that should arrive tomorrow.  The windows and locks work but it was only about $20 for all of them.  The driver's side rear window switch lets the window down but won't put it back up.  I think the passenger rear doesn't work at all.  In the coming days/weeks, I'll break out my multimeter to check all of that.   Unknown wiring harness: There's a box attached to the front driver's side of the engine compartment, right where the second battery shelf is located.  There are three plugs, one of which looks like it fits a standard headlight-style bulb (9007 or similar).  It doesn't look like it's plugged into anything.  I'll do some digging and if I don't see anything elsewhere on the site, post some pictures here.   Unknown plugs on brake booster: There are at least two female plugs on the brake booster that aren't being used.  I think it might be a replacement/aftermarket, so maybe those are used for a different application, as there don't seem to be any unplugged harnesses and no indicator lights are on.   Little squeaks when turning: Sounds almost like a bushing around the bed of the truck.  I'll have to pay close attention as I get more familiar with the truck.   Clunk on acceleration: possibly the infamous drivetrain clunk.  My 2006 had it and I'm just not familiar enough with this truck yet to fully grasp what it is.   Anyway, my apologies for the vague and all over the place post.  This truck is new to me, and it's been four years since I drove my 2006.  With 200k miles, I know I'll need to learn this truck quickly to avoid having any major issues, despite being confident it's got much more life to it.  My 2006 had nearly 320k on it when I parked it (nearly 300k of which I put on the truck), and it was still drivable then, though I suspected the head gasket might have blown.  I'd hoped to have that truck back by now, but it's gone forever, as I detailed in my reintroduction thread.  

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...