Howdy, Stranger!

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

Howdy, Stranger!

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

Did you get a great deal? Let us know in the Values & Prices Paid section!
Meet your fellow owners in our Owners Clubs

Trailer Towing with Sierra/Silverado

mikey42mikey42 Posts: 28
edited March 2014 in GMC
Ok, I got my 2000 Sierra over the weekend and it
came with the towing package. It also came with a
separate harness for the electric trailer brake
controller but the manual says I need to take it to
the dealer to install. First the dealer is a half
hour away, second all it is a plug that plug in
somewhere and hooks up to controller. BUT WHERE
does it plug in ? I cant find it. Also, my
controller takes 4 wires, +/- and brake switch and
brakes, the harness only has 2 decent gauge wires
and 3 small gauge wires, why ?

My closest dealer is a half hour away and when I
called them they said they didn't know where it
plugs in and I should bring it in and they will
figure it out. Before I drive a half hour down
there, I will find a +/- connection and splice in
the 2 brakes wires I need. I does appear to be
wired the the trailer plug for brakes the wire is
there at least.



  • dmickdmick Posts: 28
    The box location for the Electric brake controller is located under the dash Drivers side,remove cover and it is located in upper left corner. A diagram is located on the inside of the cover. You will have to splice the wires from the harness to the brake controller following the controllers diagram before you plug the connector in. The harness came with a 40 amp fuse which I don't believe you will need, I didn't.
  • dmickdmick Posts: 28
    Did you get the 5th wheel wiring provision code UY2. If you did make sure the wiring harness is there. Mine was not and it was listed on the options list. My dealer is putting it in tomorrow because GM forgot to install it. It should be located between the cab and the bed on the drivers side tied up with wire ties.
  • With your instructions, I found it durning lunch. Now I just have to figure out the wiring, there are 5 wires on the harness and I only need 4 on the brake controller, plus 3 of those wires are pretty small gauge. I did not order the 5th wheel provision just the towing package and the connector at the receiver does have all the wires. Of course in the wrong connector type for my trailers but thats easy to change. I did also wonder about the fuse but thats for tonight with the VOM and test light.
  • jaijayjaijay Posts: 162
    Yup I was in the same boat as you guys. We bought a trailer and it needed a connection for the electric brakes. You should of gotten a wiring harness with your towing package. It is just a bunch of wires that have a connector to them. They also provide you with a fuse. I beleive the fuse is to run DC back to the trailer and charge its battery. Check your glove box or under a seat sometimes this is where the dealer puts them.

    Now look under your dash (drivers side) where your left foot would be. There should be a box there with a wing nut on it. Unscrew this nut and remove the cover. There will be a bunch of fuses there and some empty sockets. On the inside of the box cover is a diagram of what every thing is. It will pin point where the harness connects to.

    It connects to the top, second socket from the left. If you look on the wires you will see that they are marked by a tag. They tell you what they are for. You must splice them to what your controler needs. One of those wires (brown I think) is for a night light to your controler. Mine, a Tekonska (sp?) does not have one so I taped it off.

    Once you have this spiced in you should be ready to mount your controler. I mounted mine to base of the cross beam that is just below the dash board. You will see this beam. It runs right near the emergency brake peddle. I did not want the controler to clutter the dash and once it has been set up you pretty much can leave it alone.

    As for the fuse, you will have to open your hood. On the drivers side there is a fuse box. Pull off the cover and on the inside all of the fuses are marked.

    Where the fuse goes is not clearly marked.

    The box looks like this.

    _____! O F B O !_______
    | U R !
    ! S A !
    ! E K !
    ! E !
    ! !
    ! !

    Execuse my drawing, The fuse should be installed on the oposite side of the trailer brake fuse, one socket in.

    Yup I went through the whole shabang. The dealer did not know too much and the trailer company wanted to rewire the entire truck? Chevy did it right however it is difficult to get anyone that knows anything about it. It is really very easy to install, it is just that everyone wants to charge $$$ to do it.

    If your brake controler is brand new, it should have information on the Chevy wiring harness. And beware, the color scheme that the controler uses may not, and in my case was not the same as the harness. Good luck.
  • I didn't have time to plug in the trailer last night since I have to get the correct plug on the trailer but using my test light, it appears to be working. Thanks everyone !
    The only question I have left is whats the fuse for ? It appears to have power and be functional without the fuse. Is the fuse just to power accessories on the trailer if the trailer has 12V stuff on it ?
    By the way I tried to order the Service Manuals today for the 2000 trucks using that number in the back of the owners manual and was told they are not ready yet.
  • the part where jaijay said the fuse was just for DC power to the trailer. So I guess I am ready to change the plug on my trailer and go play this weekend. Hopefully, I am ready :-)
  • I have just installed a Tekonsha brake controller on my new Silverado using the wiring harness. Sure makes it easy. Does anyone know if it is normal to have 12 volts at all times on the trailer brake wire (blue one) going from the controller to the trailer. I'm ready to change the trailer plug and try it out if the controller is working ok! Anyone know if the plug to change out on the trailer end is easy to come by?

    Really like the truck. LT Ext Cab. 5.3 engine.

    T J
  • jaijayjaijay Posts: 162
    I have the Tekonsha controller too. I believe that this brake wire will keep 12 volts running through the magnets all the time. The current is very low and increases to activate the magnets when the brakes are applied.

    My controller is for one and two axel configurations. There is an LED on the controller that lights green when the trailer is connected to it. When the brakes are applied the LED turns orange/red.

    The green LED indicates that a connection to the magnets have been made (current is running through the magnets at a low current).

    The trailer connection harness also has 12 volts that run from the truck to an auxillary battery/power source. I do not know which color wire this is. GM supplies a fuse with your wiring harness that is just for this wire.

    I mounted my controller so that it was out of the way of you knee. I have it mounted to the bottom cross brace that runs along the bottom of the dash board. You problably seen it when you connected your harness to the fuse box.

    Love this truck!
  • jaijayjaijay Posts: 162
    You might want to check the Tekonska instructions. It mentions in mine what wires have power back to them or runs continously. Gotta go.
  • In the Tekonsha manual it mentions that if you want to test the unit, you must do it with a test light since 12 Volts will always be there. Sure enough when I put the test light on blue it was on and the green light on the controller came on.

    Thanks to all that answered my questions on where to plug the thing in. I like this factory wiring stuff, it makes life easy.

  • about towing with my 5.3 Ext Sierra ? I tow a small car on a trailer and I used to tow it with my Toyota 4X4 using Load Levelers but the Sierra is too low and the load levelers scrape on just about everything. Since my tongue weight is only 450lbs. I thought I would try without the load levelers and it brought the truck down 3 inches till it is almost level, instead of the back end being up. My Toy was 12 years old and sagging badly in the back and since I keep my trucks a long time, I don't want to mess this perfect truck up.

    This is full size truck, yeah only 1/2 ton truck but it sure should handle this right ? By the way it seemed to handle fine over the weekend, I am just concerned about long term damage, the load levelers were so nice for towing since they raised the back end of the Toy up almost to normal. I tried many variations this weekend and the Sierra is just too low to the ground, thats not a complaint by the way, the truck is still perfect.

  • I'm not sure what "load levelers" are, but my Air Lift pneumatic helper springs were in stock at Camping World when I bought them for my '99 1/2 ton Silverado, and they work great! No scraping!
  • vince4vince4 Posts: 1,272
    quad, which Air Lift product do you have? I'm looking for the Super Duty air bags (5000lb) and today was told by Camping World that it is a special order for $299.
  • I tried towing this weekend with my new 99 1500 silverado/extcab, 5.3L, auto, 4x4, w/Z71. My previous truck had a 9000lb suspension so it never had a squating issue, but this truck does. I haul 1000 lbs of truck payload with 500-800 Lbs of tongue weight.

    Setup like this the rear dropped 3" at the receiver. This puts the headlights at the top of the trees... not good.

    I bought the 1500 because the older C20 w/heavy suspension just road too rough the 300 days of the year I was not towing. So I was wondering what you would recommend to solve the sagging issue. I don't want to make the ride any worse (its still a truck!) than it is now when the truck is empty. But I need more rear-axle capacity when towing.

    Suggestions comments welcome. Any websites I should look at?

    Overall the truck had plenty of power (w/3.73) and was very stable. The trailer is a 16' dual axle flatbed, total trailer weight (last weekend) about 3500lb. A few times a year I'll push this to 6500lb. But 500-800 on the tongue is consistent.

  • Question?
    I have a Kelsey trailer brake controller. Kelsey states in it's manual that the black power wire is to be mounted directly to the positive side of the battery via a 12 gauge wire through a 20A self resetting circuit breaker. It says a Fuse is not acceptable.
    Did GMC take this into account in the furnished wire bundle?

  • The positive connection through the trailer harness in the connection block (under the dash) runs to a 30AMP fuse under the hood. No resettable circuit breaker to my knowledge. Some brake manufacturers call for a self-resetting CB others call for a fuse. My opinion is its what their lawyers recommend to be recommended!

    Obviously some electrical protection is required, if a short develops the fuse will be a one-shot. Once tripped, no more brakes! Where the resetable CB will try to re-engage (assuming the short went away...)

    I'm using the fuse as GM designed.
  • vince4vince4 Posts: 1,272
    I responded to your post in the Silverado topic.
  • vince4vince4 Posts: 1,272
    I suspect the comment on the fuse is because a temporary surge could blow it out and then no brakes. If they recommend a 20A breaker then likely a 30A fuse would be just fine. I don't know if they make slow blow fuses for cars but that would also solve it. If you are worried about it put in a heavier fuse and pick up a breaker at an RV store. They are small, easy to install and cost about $5.
  • I was given this GM number by someone on a newsgroup. Its for a Circuit Breaker that replaces the Maxi fuse on the trailer wiring. GM part number # 12088553.

    Don't know anything about them, but I will be going to my dealer this afternoon to order one.
  • Click on the thumbnail to view my Airlift pneumatic helper spring, left side. As you can see, lots of room. My truck is 1/2 ton, thus 2500 pound rating for the Airlift set.

  • markbuckmarkbuck Posts: 1,021
    What's that big groove on your rear disc?
  • mgdvhmanmgdvhman Posts: 4,162
    I wasn't gonna say anything...but now that the ice is broke....we know what it get rid of it!

    - Tim
  • When you're tryin' to slow down a Vortec, your brakes have to be up to the task!
  • vince4vince4 Posts: 1,272
    Thanks for the great picture, really clear. How do you sneak that photo in a text message?

    Someone mentioned a problem mounting similar air bags because the frame is boxed in that area. Is that true in your case? How did you handle it? Are those bolts self tapping or do they have a nut on the back?
  • You embed your text with html codes to put in the photo and link.

    Bolts are not self tapping. There is a locknut on the back. The metal frame rails are soft. You can drill easily right through a weld bead, which I had to do to properly locate the bracket. The back side of the boxed frame rails are open. You have to slide your hand in there. It's tight, hardest part of job. At least there are no fuel or hydraulic lines in your way on the Silverado. I didn't believe it could be done so I called the AirLift 800 number. They told me that, can get your hand in there so quit whining. And I found out, it is possible, but I was battling doubt, until the last nut was tight. But I think the whole job took about 3.5 hours, without hurrying. Did you see my shrader filling valve in the fender lip? I didn't want on-board compressor, wiring, long hoses etc. Just felt it was something to go wrong. I carry a bicycle pump. By the way, don't link the two air bladders to each other. Keep them separate, so when you are cornering, you don't get extra lean caused by air in the outside bag transferring to the inside bag.
  • vince4vince4 Posts: 1,272
    Thanks for the info. Good tip on the air lines but I am getting the dual guage on-board compressor so I can adjust to any situation. I hope to get a little adjustment for leveling a camper in the campground as well but I don't know how much travel I can expect. I'm getting the Super Duty bags which mount directly over the axle which is a little different than yours. Now it's a contest to see which will arrive first, the bags or the truck.
  • Leveling for your camper will be a snap. Let me know how the compressors work out. I don't know how much travel you will get, or need with your 3/4 ton. But on my 1/2, it is more than satisfactory. You can inflate them to 100 psi, but I can overload the cargo, camper, GVWR, all the way up to the GAWR, and with just 50 psi, the bed is still above level.

    You start by measuring what "level" is. The distance from the axle center to the fender lip. On my truck it was 23.0 inches. After the bags are installed, you have to maintain a minimum pressure of 10 psi. That ends up raising the bed up another 1/4 inch above level. You can raise the bed up exactly how high, I am not sure. Quite a bit. The instructions say that is a mis-use. You are supposed to level your load to the stock height (+ 1/4) at all times.
  • vince4vince4 Posts: 1,272
    I ended up buying the Air Lift compressor & guage package for around $160. Firestone makes a better one with a heavier compressor and a 1/2 gallon storage tank. You can add a hose and use it to fill tires etc. The problem is it costs over $300 which is just too much for a simple air bag application on a light truck.

    When I level my camper with wheel ramps I usually need around 4" of lift. I doubt I'll get that much from the bags alone but they should help.
  • mgdvhmanmgdvhman Posts: 4,162

    With 3000 lbs in the 3/4 only went down a few inches. Not sure how much travel it will give you. it's one stiff puppy!

    - Tim
  • I think 3 inches down would easily have your axle resting on the jounce bumper. You'll always have more drop at the hitch then you would have near the axle.

    I am less skeptical that you can get enough to level it from the bags alone. I think those 5000 lb bags will level your camper EASILY.
    A friend of mine has them on his Powerstroke Dually, and easily levels his ponderous 5th wheel camper. Let me know if I'm wrong.
This discussion has been closed.