Chevy Silverado and GMC Sierra Trailer and Towing Questions

davethecarnut · April 2009

If your wondering whether its 3.73 or 4.10 he's definitely got a 3/4 ton which is fine for a 30 ft trailer. If you're not the original owner, did he at least give you the build sheet? That will definitely tell you.

davethecarnut · April 2009

Billy Bob, you definitely need a big block V8 or diesel for your application to stay in the green zone. Keep looking.

thom56 · May 2009

I have a 2001 Silverado.it came with factory installed trailer package. installing the controller and the wiring to the under dash junction block is done.
i found the blunt cut end to the factory installed wiring harness leading to the hitch.
but,i cant find where to attach the cut end to the main wiring harness.
if anyone knows where this is done,please let me know.

thom56 · May 2009

update: mystery solved.it may be used for a fifth wheel trailer .

davethecarnut · May 2009

Were you refering to the "blunt end" to the bundled wire that was behind the cab?
Then, yes, that wiring is for a camper add on or to put a plug in the bed for a 5th wheel trl.

3839 · June 2009

I have a 2002 6.0 1500 HD. I have put a hypertych programmer on// changed the front -rear gears from 3.73 to 4.56// changed orig exhaust to magnaflow// and i still have a serious problem pulling a measley 6800 lb. rv trailer up inclines and hills and starting off. W H Y ????? maybe hi flow cat converter needed and new cold air intake system ??? please any advice!!!

davethecarnut · June 2009

What you mean by "problems", Willis? Seriously, how fast (or slow) are you going uphill? Are you an experienced trailer puller? Because an RV and, say, a trailer with some dirt bikes are two different animals. 4.56's?? Did you put taller tires on your truck?
To compare: My 496 (I refuse to go metric) pulls my 9500lb 5th wheel up a 6% or so hill around 45 mph. Maybe 50 if I push it and the hill is short. It's factory stock. And the Allison is a great transmission.

hrsgrl · June 2009

I have a 2006 Chevy 1500 crew cab with 5.8 bed. I am looking at getting a goosneck horse trailer, but am worried about the truck handling it. It has the 5.3l V8. Trailer weighs 6000 lbs. Anyone done any towing like that with this truck?

obyone · June 2009

Is that 6000 loaded or empty?

davethecarnut · June 2009

First off: I see clearance problems. You said gooseneck. I know they make sliding 5th wheel hitches but I don't know about gooseneck balls.
Is 6000lbs the trailer's GVW or is empty weight? Your truck will do fine with 6000lbs but not with 2 or 4 horses in the trailer. Your truck would be fine with a 2 horse pull trailer.

cprovost · June 2009

I have a 2006 GMC 1500 crew cab with the 5.3 and i towed a bobcat that weighs around 9000 lbs. I had no problums and hauled it 95 miles none stop and it was great. Had no problums taking off are stopping.

jeannep · July 2009

I am looking at 06 GMC 1500 sierra longbed,truck cab, 4.81 vortec v8, AT, to pull 2 horses & trailer, 6,500 max weight. Does not have tow hitch, but does have "tow mode" switch. Not planning any long trips, just local rereational.Will this work?

davethecarnut · July 2009

No factory tow hitch usually means no heavy duty radiator or trans cooler.
But "local" towing you should be okay. Max towing capacity should be found on the decal in the pillar of the drivers door

jdsprad · July 2009

Does a website exist where I can enter my VIN, and bring up all of the vital info of my truck, similar to that found on a window sticker at the dealer? I recently purchased a 2004 GMC 2500 CREW (6.0L), and the seller did not have the original sticker, nor did he know what gear (rear-end), or transmission that the truck has. Did GM install more than one type of tranny in the gassers for that year? I got a heluva deal on the truck, so I am not real concerned, but still need to know exactly what I have here. Any help would be greatly appreciated. Thanks.

akjbmw · July 2009

I requested a build print-out based on the VIN from the local Chevy dealer on the last three vehicles I have bought used. They did not charge for it.

Back in the "olden days", I did the lift one tire off the ground: chalk mark on the drive shaft (flange bolt was convenient) and the lifted tire edge, then turn the wheel (counting the turns) until the shaft completes a full turn. Divide the number of wheel turns in half and convert to decimal.

The dealer print is very handy to reveal surprises in the form of unknown adds and deletes. Our sedan had been ordered with light duty front disks and side air bag delete. I was a bit disappointed, but it's a good thing to know. The Duramax had more stuff than I knew about, cool to know about.

jeannep · July 2009

Dashboard light stays on indicating doors are open. Takes 10-15 min for overhead, door and cargo lights to go off after shutting down. overhead light stay on 5 min after starting engine. Tried the WD 40 on the hinges, did not work.
Any suggestions?

jdsprad · July 2009

Picked up a "build print-out" today from the dealer. Thanks for the help.

gutelius · July 2009

How do I hook up after market Electric brakes on my 2009 GMC Sierra

oakb · July 2009

08 Silverado 1500 4WD Crew Cab, 5.3L Vortec, 3.73 rearend, 4 speed tranny, 20" tires summer, 17" winter and Z85 handling/trailering suspension. Looking at 6700 lb 5th wheel (will use sliding hitch) for 1-3 hr trips with minor elevation changes and 1 long trip with elevation changes. The truck is rated for this the way I understand it but looking for practical input from folks with real world experience.

bcouv1 · August 2009

I have just installed a brake controller on my 2006 Silverado 1500. I have installed the 40 amp fuse to the #1 Stud position in the box under the hood. I still have no voltage reading on the red or blue wire connections under the dash where the trailer brake harness connects too. Any clue?

dmoore524 · August 2009

I have a '04 Silverado 1500 with the heavy duty tow package. I use the truck to pull a bass boat on occasion. I try to remember to unplug the trailer lights so nothing shorts. I must not have remembered once, because I have no power for the lights. The fuses at the side of the dash and under the hood are good. there is no power to these fuses at all. Is there another inline fuse or something I am missing. I'm usually pretty good at troubleshooting but I'm at a loss now. Thanx.

pantera123 · September 2009

pantera123 · September 2009

I have no power to the constant 12volt connection on my female trailer plug on my 2002 Silverado 1 ton. It has the 7 wire plug from the factory. I can't locate a fuse for this wire. Any help would greatly be appreciated. Thanks.

brandon_09 · September 2009

Ok i have a chevy silverado 1500 and when i pull my camper it over heats.I have the transmission cooler on it but every time i pull it it seems to over heat is the Chevy silverado 1500 just not able to pull that kinda load.

grizzly4 · September 2009

How heavy is the trailer? What year is your truck? What is the rear end gear ratio? What size motor do you have?

oakb · September 2009

Did the research on all the items you suggested and more and just bit the bullet and bought a 3/4 Silverado diesel with the 6 speed Allison. This way there was no limiting factors as far as tow vehicle. Ended up with a 34 ft fifth wheel and am very happy. Thanks..

grizzly4 · September 2009

Sounds like you have a nice truck and trailer. Enjoy! Now bring it to Montana sometime. It's beautiful up here.

davethecarnut · September 2009

Yeah..that 34' 5th wheel is slightly heavier than 6500lbs

You got a great powertrain combo. Did you still get a shortbed? And did you buy a sliding hitch? Which one did you buy?

oakb · September 2009

Thank you. Montana is on the list but it is a big list....

oakb · September 2009

6ft bed, my uncle had a Reese non- slide that he was not using since he upgraded to a slider. I bought a Cougar 5th wheel that has a new nose that eliminates the problem of hitting the cab so I feel safe using a non-slider. Thanks for the help....

countryboy34 · September 2009

countryboy34 · September 2009

i just recently bought a 1500 sierra with a factory installed tow package and wnat put hook up electric brakes for towing. i have read that all i need to do is plup in the controller in under the dash which i found. i know other people that have done this and needed to get a resetable circuit breaker for it. do i need to get one or is it all set to go. and if so where is it? is it a fuse or a circuit breaker. also anyone know what the wiring diagram is on the factory 7 plug for the trailer? are one of the slot for a constant 12v accewsory? do i need a fuse for it or anything else to hook it up. cause i checked with a volt meter and i couldn't seem to find one. any help would be appreciated

harrisoncrazy4 · October 2009

harrisoncrazy4 · October 2009

Looking to buy used truck, but not sure if it strong enough for what I have. I tow my trailer with a F150 and I hate knowing it is too small for my trailer. 10,000 lb. trailers are heavy, do I need to worry with a 6.0L HD?

etmegabyte · November 2009

Quote: I have a 2005 2500HD with the Duramax, with the same problem of no aux power in the trailer connector. I checked in the manual and it says DO NOT install a fuse in the STUD 1 location on vehicles equipped with the diesel or 2 batteries..... I have both. Any ideas?

---

I spent quite some time today going through my 2003 GMC 2500HD truck trying to get an answer to this very question. And I think I've figured out why...

My truck has the plow prep package and the towing prep package. It also has dual batteries. I found that part of my dual battery setup connects an extra wire directly to stud 1 (not the fuse location, the actual stud below the plastic cover) that gives it power when the key is in the "on" position. This effectively makes stud 1 a switched power source.

If one were to put a fuse in the stud 1 spot, then it would make the trailer wire live all the time, but it would also feed power back into some portion of the dual battery setup as well, which I would think is bad... There has to be a reason for the switched source, and I assume that GM had a reason for making stud 1 switch that way.

I'm assuming this power feedback would cause some other things that are expected to be off when the key is off to stay on all the time...

And, if you think about it, it makes a certain amount of sense. Why would you want to charge the trailer battery without the truck running? You'd want the power switched so that your trailer can't drain your truck's batteries... However, you'd want to run off of the truck's power if and only if there's an "unlimited" source there. You wouldn't want to drain the truck's battery by running your trailer off just the truck battery. But running the trailer off the truck's alternator? That's a better idea. This adds more credence to the idea of only powering it when the truck is in the "on" position, because 99.9% of the time when the truck is in the "on" position, it's running...

I think if you checked your 12v wire in the trailer connector, you'll likely find that it is dead when the key is in the "off" or "accessory" positions, but is live when the key is in the "on" position... At least, I did...

Hope this helps.

-ET

etmegabyte · November 2009

pantera123, do you have a dual battery setup? Have you checked if there's power to the 12v constant when the key is in the "on" position? My 2003 2500HD has dual batteries, and the 12v wire is switched on only when the key is in the "on" position.

If you DO NOT have dual batteries, then you have to put a fuse in "Stud 1" position in the fuse box under the hood. If you do have the dual battery setup, the trailer 12v constant *should* be switched without the fuse...

etmegabyte · November 2009

I think you hooked up the wrong wire.

the 40 amp fuse in the Stud1 connector should go to the solid red wire (which was taped under the master cylinder?), which is the 12v constant to the trailer harness.

What you're looking for is a Red/Black (I think that's the right colors) wire that connects to stud 2. I believe that wire is taped between the underhood fuse panel and the inside fender wall...

I get the locations of the two confused, because both are already hooked up on my truck. But one wire is taped under the master cylinder, and one is taped between the underhood fuse panel and the left inner fender wall. They are two different wires, with two different sized ends, and each will only properly fit on one stud or the other. I do know for a fact that the stud-1 wire is the trailer 12v constant wire, and the brake controller is the one that connects to stud-2...

Hope this helps...

etmegabyte · November 2009

countryboy34, First off, the 7 pin plug at the back of the truck is standardized. It won't change from truck to truck. Looking into the plug from the back of the truck, the wiring should be as follows: (Also, on my 2003, my stock plastic cover over the jack itself also shows the wiring diagram as well - if you look closely, yours might as well)

You should note that in this picture, the wire "colors" are incorrect, but their positions are correct. This is standard 7 pin wiring. The Auxiliary pin in the middle is setup from the factory as the reverse light lead.

There are two wires under your hood that need to be hooked up. One of them powers the 12v port on the trailer connector, and the other is the power lead for the electric brake harness under the dash. I forget which wire is where, but one of them is taped on the firewall under the master cylinder and the other is taped between the underhood fuse panel and the inner fender. They're two different sized wires, with different sized ends. One of them connects to "stud 1" and the other connects to "stud 2". The ends are sized to properly fit on only one of the studs each, so you can't mess it up... Finally, be sure that there is a 40a fuse in the "stud 1" location, and a 30a fuse in the "stud 2" location.

for a 2004, you should be pretty much plug-and-play to connect the electric brake controller in the cab. But once it's hooked up, verify VERIFY VERIFY that all lights work properly on the trailer, and that the trailer brakes don't lock up when you turn on the headlights. Some Chevy/GMC harnesses under the dash are incorrect and lock up the trailer brakes when the headlights are turned on. If this happens to you, I hear it's just cutting and switching two wires around, but I don't have the details on that...

So, it's definitely not going to be a 5 minute install, but if you spend some time researching the points I've made here before you go hooking up wires, it can be a 30 minute install including testing...

Hope this helps..

cam77 · November 2009

I have been trying to determine whether I can tow more than the 6700 lbs listed in my owners manual. I purchased a new '09 GMC Sierra 1500 extended cab with the standard bed. It has the 5.3 LMG engine with flex fuel capability, it's coupled to a 4 speed auto, and the rear gear ratio is 3.42 with the locking rear differential. It was upgraded with the heavy duty towing package, the HD trans cooler, and has the Z71, and z82 packages. This will be used to tow a lightweight fifth wheel. I contacted GMC and they couldn't help. I have looked everywhere and can't determine whether the packages improved the payload or just added a safety factor to towing. Any ideas?

Thanks

chrismicrobu · November 2009

My 2007 Sierra tows up to its rated load well, and may comment on its ability to haul beyond its rating when the truck has surpassed its warranty....Wish the truck was available with a manual trans. Equipped with the tow pack, trans cooler, snow plow prep(and I plow with the truck), 4 speed auto, 3.42 auto lock diff., 4.8L V8. I added an electric brake controller to this truck, and feel it's added a margin of safety.

canddmeyer · November 2009

Try this link: http://www.gmc.com/sierra/1500/specsCapabilities.jsp

Here's the link for the Silverado: http://www.chevrolet.com/assets/pdf/owners/manuals/2009/2009_chevrolet_silverado- _owners.pdf

free12 · November 2009

I pull a 3000lb 20 foot bass boat with my 2001 with a 5.3 4x4. It pulls very well, but, like everything else you have to stop it. Any vehicle will yank a trailer, but if you can not get it to stop you are in trouble. When I see a suggested towing capacity of a vehicle I always picture in my head the size of the trailer they are talking about. For example, a 7,000 boat might be a 25 foot cabin cruiser on a 3 axle trailer. Can you picture yourself driving a Grand Cherokee Jeep or Chevy Trailblazer pulling this? And then safely stoppinig it? Not me, I always go for the over-kill.

Another item that is of the utmost importance is the hitch and ball rating as well. Seen too many people bolt on a hitch to the bumper and then try and pull huge trailers.

4x4rider · December 2009

I have a 2002 HD with a trailer package. All of a sudden the trailer lights are acting up. The turn signals work fine by themselves. When I turn on the lights or apply the brakes, the opposite turn signal blinks and the corner lights come on. Any thoughts???

tymyers · December 2009

Check your ground wire. Most commonly this comes loose at the trailer end where the installer or manufacturer ran a short piece of wire (typically white or green) from the multi plug of your truck to the chassis of your trailer. If it isn't kept clean and free of corrosion, it will often get gunked up to the point of loosing conductibility. You can usually test this by loosening the screw a touch, then shifting the terminal side to side to scrape away the corrosion. It is also possible that he copper wire has corroded through and needs to be replaced. Anyhow, usually if your lights still work, but work "erratically", it's due to the ground. When your main chassis ground goes, then the lights find a different path to ground, which is usually another light that isn't being used, or isn't supposed to be on at that particular point in time, causing all sorts of craziness. Good luck!

4x4rider · December 2009

Thanks for the info. I forgot to mention the same thing happens on another trailer, so my guess would be there is a problem with teh ground on the truck, correct? It's a factory installed harness, any idea where it might be grounded?

tymyers · December 2009

No, not right off. If the weather clears up today, I'll crawl under and see if I can figure it out on my truck. Usually the ground wires get screwed to the chassis somewhere near each and every device or harness. There are some exceptions, but very few. So I would start by following the harness wire bundle a short ways to see if one wire branches out and screws to the chassis. It is even possible that the harness itself grounds to chassis. Another option, if all else fails, would be to add a new ground wire where one end screws to the truck frame and the other end screws to the trailer frame, with some sort of quick disconnect in the middle. Not ideal, but if in a pinch, and you can't find the problem in the truck that would allow you to be legal. Also, minus the quick disconnect, you could use it for troubleshooting to see double check if it is indeed a ground issue. I'll post again if I come up with any more information on the harness and ground.

4x4rider · December 2009

Awesome! I'll see what I can find.
Thanks

artm7 · December 2009

I just bought a 2006 Silverado 3500 2WD with trailer towing package and am preparing it for a truck camper that we also just bought. The truck has the factory harness as well as a plug in the box for a goose neck/fifth wheel. I built a extention cable to reach the front of the box for the camper plug. In testing it(both turn signals worked fine) I accidently short the tailight wire to ground. Now all plugs, including the factory plug under the bumper, are 100% dead.

Where is the fuse that controls the trailer harness???? I've checked all fuse blocks and can't find anything. Is there an inline somewhere?

Thanks,

ArtM7,

4x4rider · December 2009

On my 2002 1500HD all the trailer fuses are under the hood in a box on the drivers side fenderwell.

santagiant · December 2009

On my 2001 chey 2500 4x4 the fuses are either in a box under the hood on the drivers side or at the very left end of the dash, on the end cap. Open the drivers door and look at the end of the dash.

Chevy Silverado and GMC Sierra Trailer and Towing Questions

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