Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!

Chevy Silverado and GMC Sierra Trailer and Towing Questions



  • 1offroader1offroader Posts: 208
    I followed the instructions below from a previous post. Followed instructions exactly, everything went well, except that after sitting for a couple days the battery is stone cold dead. BTW I installed a Prodigy controller. Any ideas??


    This took me a little research to get right and even the dealer who sold me the truck didn't know.. so here is the scoop! There is no pigtail wire set for the 2007 silverado ( new body style ) and even if you got the max trailering package the dwebs at chevy didn't wire the trailering electrical or the brake control wiring for you! What were they thinking....well they are offering an in dash brake controller in thier following series and they prewired it for that option.
    1) There is a bundle of blunt cut wires below the dash to the left of the steering column above the fuse box that is labeled and tucked around some other wires. Pull the blundle down. There will be 5 wires, with black electrical tape on the ends. Red and Black is the hot , positive battery wire, white is ground, negative. Blue and white is the input tail-brake light wire and the all dark blue wire is the trailer output brake voltage. The last wire, I believe , is for the brake controller light, but I am not certain. I did not use that wire. Consult your instructions . The next step is to open the hood, take off the top on the fuse box and locate space 65 and 70. Get a 40 amp fuse and put it into space that is labeled 65, this is the brake output voltage fuse, the voltage to your brake controller, post 65. the 70 space has a 30 amp fuse in it. Now go between the left fender and the fuse box and locate the red/black wire. This is attached to the post that is larger and silver on the front of the fuse box. Nuts not included. They are metric 10-1.5 course. the other black post is 8mm. Get the red black wire wrapped below the master cyclinder and attach it to the black post ( smaller ). You can't make a mistake with the wires because they can't be attached to the incorrect post, one is smaller than the other ( the opening ) The jist is that you need 2 nuts and a 40 amp fuse. Not supplied with the truck... now.. You are set. The reason for wiring the brake controller to the post is for 12 volt use from the main batter. If you use a secondary auxillary battery the wiring will be different . Good luck and thank chevy for making this a mystery or misery as the case may be. Read your manual under brake controller and it seems a little more clear, but just a little. I read it over about 3 times before I understood what they were getting at. Boy how could they not wire the trailering wiring.? Duh!.
  • Can someone please enlighten me about this? In past years, GM full size trucks came with a wiring harness that was about 12 inches long and was located loose in the glove box. I believe this was a trailer wiring harness extender of some sort. I think you would have plugged this into your bumper and then attached it to your trailer. I may be off here. The reason I ask is because I took delivery of my new 2007 GMC Sierra Denali AWD a couple of months ago and it came with no such wiring harness. My truck has the Z82 package and has the full towing package (class IV, I think). The dealer says they've never heard of such a thing. Any information would be much appreciated. I pulled the following off of a GM site and I think it references what I'm talking about:

    "Z82 Heavy-Duty Trailering Equipment Package includes trailer hitch platform and trailer electrical connector"

    Z82: TRAILERING EQUIPMENT, HEAVY-DUTY, includes trailering hitch platform and 2-inch receiver, 7-wire harness (harness includes wires for: park lamps, backup lamps, right turn, left turn, electric brake lead, battery and ground) with independent fused trailering circuits mated to a 7-way sealed connector, wiring harness for after-market trailer brake controller (located in the instrument panel harness), and single wire for center high-mounted stop lamp, (K47) high-capacity air cleaner and (KNP) external transmission oil cooler (Included with (NHT) Max Trailering Pack. Included with (PCY) Towing Package.)
  • obyoneobyone Posts: 8,065
    I think you had it correct when you stated "in past years" as I haven't seen what you're describing since my '00 Denali.
  • hotel1hotel1 Posts: 50
    Look at this post with pics. to wire up a trailer brake
    controller to the NBS GMT-900 trucks.

    It shows the interior blunt cut wires and where their
    hidden along with the 2 wires hidden under the hood
    that need to be hooked up............. oller
  • Update to my own original post.

    I tried to duplicate making the truck battery go dead, couldn't do it. I left the controller installed and connected, and let the truck sit for 3 days just like before. No problem, truck started right up. I also checked the amperage that the controller draws while at rest, the specs say it should draw 15 mA, and it does. Everything seems to check out fine. I even had a friend who is extremely knowledgeable about electronics (he designs radar antennas for a living) check my wiring & etc. & he gave it a thumbs up.

    So.....I think what happened is that I left on a dome light, left a door partly open, or etc. & the battery drained. There appears to be no problem now, & I could not reproduce the original problem under the same conditions. However, I think I am going to install a good quality switch on the black/red hot wire under the hood located between the fuse box and fender. This is the power supply wire to the controller. When I'm not towing (98% of the time) I'll just turn the switch to 'off', that way there is no possible way for the controller to drain the battery. When I hook up the trailer I can just pop the hood open and turn on the switch to power the controller, and I'm ready to go.

  • i just finished my 01 s/rado with a protige control are you wireing the black and red both hot??wrong the black is hot 24/7 the red hooks to your brake lite hot when pushed.white is ground blue goes to activate trailer.its sounding like you are not going to the hookup under the box located at your left foot.if your truck came with the tow pac.ther should be the pig tail in the g/box.mine never so i had to run the blue wire back the frame.the pigtail at the rear needs 8 wires mine had six.i was missing the brake wire and the 12hot all the time(interior camper lite)
  • 01rado

    No. Under the dash, the black/red truck wire goes to the Prodigy black wire (hot). The light blue/white truck wire goes to the red Prodigy wire (brake light). The dk. blue to dk. blue (trailer brakes), and white to white (ground). Under the hood, I connected the 2 black/red wires to their respective posts on the fuse box, and installed a 40A fuse in slot 70 in the fuse box. That's all there needs to be done.

  • you may be right i just did the hookup on a buddys 05 that had the p/tail in the g/ you have a test lite the connecter on the bumper should tell the story you should have the blue at the bumper a real dim on your test may have a diffrent protigee mine has 4 wires black,red,white,blue.i think you are right by the way you are saying you hooked them up gm give me a runaround .my buddys 05 was a 5 minute job as he had the tow pac
  • 70,000 original miles? Or has the odo turned over a couple times?
    Get the brakes checked.
    If you drive in cold weather, a heater core will be necessary.
    Yep, 8 mpg if you're lucky.
    The new trucks are alot more efficient and built tougher for towing but they don't have that "classic" style.
  • I have a brand new 2500HD Silverado with 700 miles on it.
    It uses a factory trailer braking system, which is new to me. When pulling my toy hauler, and applying the brake, the engine races and the RPMs go up to about 2000 to 2500 as the vehicle is slowing down.
    I am not sure why this is happening nor am I sure what I may do to eliminate this from happening as it seems that the engine should not race as the vehicle slows.
    Can anybody provide any guidance e.g., is the gain set too high, too low, something else?
    The dealer says don't worry.
  • Umm...Did the tranny downshift? The Allison is electronic and will downshift under a load even if you don't have the Tow/Haul button on.
  • 2007hd2007hd Posts: 2
    The tow haul button was on and, yes, the tranny downshifted but would that make the RPM increase? It seems as though it should decrease while slowing. Thanks for the reply, was starting to wonder if anybody had seen the question.
  • It is doing what it is supposed to do. The trans has a brake sysem that uses engine compression to help in the braking process. This is similar to the Allison transmission and a great change to the Chevy line up. I was pleasantly surprised to have this feature as standard. So to answer your question, Yes the RPM will go up when the trans downshifts in this mode.

    This is intended as a trailer braking aide, not to be confused with a brake controler.
  • I have a 2000 Silverado 1500 with less than 50,000 miles on it that I pull my travel trailer (Jayco Feather). A friend advised me on our last camping trip that my brake lights on my Travel Trailer were not working. The brake lights on my truck work fine as do the turn signals. Turn signals work on Trailer as well. I had my camper dealer check for an electrical or fuse problem. They check the pigtail as well as all of the fuses under the dash as well as the ones under the hood on the Driver's side. I was told that they could not locate the problem at any of those places. I then took it to a friend's independent auto sales and service business and they kept it a day and told me that the problem was in the steering column with the emergency flashers. They said that there was a short in the emergency flashers and the system/unit would have to be replaced to the tune of 300.00 + dollars. I have had others suggest that this does not sound like it is the problem. I don not know what they are basing their opinion on and I am not a mechanic. Can anyone advise me as to the reasonableness of this recommended solution?


  • Sounds almost like the same problem I had on my 04 silverado... The independant dealer is close but the problem wasn't in the steering column it was in the flasher fuse. The chevrolet Dealer spent two days tracking down the problem and after endless tests they changed out the flasher unit and it works great.. After that they found out that a bad ground on the trailer was causing back feed and it melted the connections inside of the unit.. I would suggest trying that first before spending 300.00 on the shop..Go to your local part store and pick one up you can get them cheap and easy to install.... Good luck
  • I'm having the same issue on my 2000 Silverado Z71. And I do also have a problem with my hazard lights. Had no idea the two could be connected, but I've looked everywhere for a fuse specifically for trailer brake lights and I can not find one. All fuses appear to be fine. Guess I'll have to bite the bullet and get the hazards fixed, I was gonna let them go and not worry about them. The work if I push them to the right but they are almost impossible to engage. I never could simply depress the button without hitting it with my fist several times.
    Please post if you discover another cause.
  • Well The part is called a Hazard Flasher.. And the location is probably going to be under your dash on the driver side..On my 04 it's located close to the steering colume.. but it could anywhere on the driverside under the dash.. if you turn your hazards on you may her it ticking from under the dash... There is usually two of them that may look like. one is for your blinkers and the other is your hazards... I't usually a square shape.. Part number should be 44120.. I would also suggest that you check your ground on your trailer once you fix it. Take it loose from your trailer and clean the area really good, make sure there is no rust or paint between the connection.... Hopefully this helps, I know it can be a real pain.. It took almost a month to figure it out..
  • Well, in my case it absolutely turns out to be a defective flasher switch. My hazard switch has always been difficult to turn on and I noticed it stopped working the other day unless I held it just right. Tonight I plugged my trailer light tester into the plug on my Z71 and all lights tested OK with the exception again of the trailer brake lights. I had my brother watch the lights on the tester while I wiggled the hazard switch and if I pulled it hard toward the door while pressing the brakes the tester brake lights came on. Gotta be the switch then... no fuse, no flasher problem. I did a little more research and found that this problem has also been reported and a recall issued for the 2000 Malibu and the 2000 Blazer.
    I think I'll try taking the articles to my dealer and see what they say. It's worth a shot. - 037&SearchType=QuickSearch&summary=true - earch&rcl_ID=01V364000&summary=true - earch&rcl_ID=01V364000&summary=true

    Hope this helps somebody out. Thanks everyone for taking me in this direction.
Sign In or Register to comment.