2500HD ZR2 First Tow

[AXE]

I went quail hunting this morning, so this was my first tow. Nothing too exciting as my trailer and SXS is only about 4500 lbs.

When I hooked it up, it maybe had just a little bit of squat, but trailer had a little weight forward on the pin the way I have the sxs loaded.

This truck really tows nice. The 10 speed transmission is smooth as butter and always seems to be in the sweet spot. There's a couple step grades and I never really noticed the shifts. Maybe seen a couple hundred +rpms at most.

The suspension seems to work even better when some weight is added. It rides really nice, especially on some choppy pavement at 70 mph and some rough desert roads with washboard and rocks. Never did that stretch of road with such ease. That alone may be worth the price of admission. It rides nice without a load, but better with a load.

Probably the only thing I didn't like was the adaptive cruise going back down the grades was very aggressive when encountering slower traffic. The brakes and exhaust brake would kick in and it would scrub off about 12+mph abruptly. Then speed up quickly. Some of that might have been due to all the shitty drivers in front of me stabbing their brakes and switching lanes.

My trailer wire kept showing a disconnect/reconnect message in DIC. It seemed solid at plug. May have to check pins and wiring. Never had that with this trailer before, but could be the wiring on trailer as it's getting older.

Overall, very happy with performance when towing!

 

[8ball_99]

The trailer disconnect/reconnect message is a bit concerning. I had issues with my 1500 brake controller when I first got it. Figured they would have the trailer wiring sorted properly on the HDs. Especially after all the initial problems with the early 1500s

 

[AXE]

The trailer disconnect/reconnect message is a bit concerning. I had issues with my 1500 brake controller when I first got it. Figured they would have the trailer wiring sorted properly on the HDs. Especially after all the initial problems with the early 1500s

I recall you posting about this before. I'll have to revisit that discussion. I do know that the trailer lights always worked despite the disconnect warning. Trailer brakes were definitely off. Seems like more of an issue with computer than the wiring or connection.

GM's motto is "if it's broke, don't fix it! These crappy electronics will continue until at least the next model. They've proven that model with emissions/DEF systems and CP4 fuel pump......just let it ride.

 

[8ball_99]

I recall you posting about this before. I'll have to revisit that discussion. I do know that the trailer lights always worked despite the disconnect warning. Trailer brakes were definitely off. Seems like more of an issue with computer than the wiring or connection.

GM's motto is "if it's broke, don't fix it! These crappy electronics will continue until at least the next model. They've proven that model with emissions/DEF systems and CP4 fuel pump......just let it ride.

My issue was slightly different. I was getting "problem with trailer wiring, trailer brakes disabled" My dealer was able to fix mine in a couple hours. Lots of guys weren't so lucky. Gm later came out with a service advisory about that problem.

What ever you do, try a different trailer before you assume it's the trailer. New truck and that trailer had just had some work done, so I assumed it actually was the trailer wiring. I hoisted it up and rewired the whole trailer lol. Only to figure out the truck was the problem. plus side is every connection on that trailer is solid and water tight now.

 

[AXE]

My issue was slightly different. I was getting "problem with trailer wiring, trailer brakes disabled" My dealer was able to fix mine in a couple hours. Lots of guys weren't so lucky. Gm later came out with a service advisory about that problem.

What ever you do, try a different trailer before you assume it's the trailer. New truck and that trailer had just had some work done, so I assumed it actually was the trailer wiring. I hoisted it up and rewired the whole trailer lol. Only to figure out the truck was the problem. plus side is every connection on that trailer is solid and water tight now.
View attachment 8586

Yeah, I'm gonna inspect trailer wiring and battery first. Then I'm gonna test trailer with my 1500. Then decide if she needs a trip to dealer.

LOL...... I'm already planning to replace all my lights with LEDs and also the break away wiring. Also thinking of repainting with rattle can. I redid the brakes and hubs last year, cause one of them got hot. Redid the decking about 5 years ago.

Other than my firearms and precious metals, that 16 foot tandem axle trailer is the only thing I've owned that appreciates in value. They go for 3X what I paid and most aren't as heavy duty frames. Way better than buying trucks.

 

[8ball_99]

True about the price going up and quality going down. Unfortunately I've had two trailers stolen in recent years. So a couple of mine are newer. The one in question was a new trailer. It's almost a running joke now anytime I fix one up.

Both trailers that were stolen were older. They got taken right after I had completely redid them. Paint new decks repaired any damage and all new lights and wiring. It happened once and I was unhappy. About a year later I fixed up a different one and sure enough with in a month it got stolen, lol. Different trailers taken from completely different locations. So now if I do any repairs on one, I'm pretty paranoid for a couple months after. I joke now that I don't want to make them look too nice.

 

[AXE]

Damn that sucks! I've had my truck broken into three time and had a bunch of tools and gear ripped off. About 20 years now since I've had a problem, so I suppose it'll happen again.. Nothing worse than a damn theif.

 

[8ball_99]

Damn that sucks! I've had my truck broken into three time and had a bunch of tools and gear ripped offtheir. About 20 years now since I've had a problem, soni suppose it'll happen again.. Nothing worse than a damn theif.

I agree, hate theives. I've been pretty lucky other than those trailers. I do have a three camera dash cam that records 24/7 in my ZR2. The trailer that gets around the most has a GPS tracker now lol. I actually put the tracker on the new one and parked it in the same spot the one got stolen. Put a wireless camera on it and Just left it there hoping the previous theives would do it again. No luck though. At my home, I never have to worry about anything like that, thankfully.

 

[AXE]

My service advisor said it might be related to TSB 23 NA 149. Sounds like many HD trucks affected in the RV forums. Of course, I did not have a trailer with a solar panel or generator running. Just the break away battery on my utility trailer.

 

[8ball_99]

My service advisor said it might be related to TSB 23 NA 149. Sounds like many HD trucks affected in the RV forums. Of course, I did not have a trailer with a solar panel or generator running. Just the break away battery on my utility trailer.

My issue on the 1500 said they replaced switch not the module. So other problems with the same system, but atleast it's not the same part failure.

 

[AXE]

I did some more testing and have confirmed the issue is somewhere in the truck BCM or wiring.

I hooked up my 1500 to trailer and everthing worked fine.

Hooked up 2500 again. Jacked up the rear of trailer to get brake axle off the ground. Tested all the lights and braking functions and everthing worked fine including testing with manual brake controller. Except the hazard lights were intermittent. I noticed that the day I towed as well. Trailer wasn't moving, so I know it isn't wiring bouncing around.

Only other thing I noticed with brakes is about a 1+ second delay before the magnets lock into rotor to activate brake. Never tested it this way before, but always seemed like no delay before. Both trucks were the same.

Checked codes and had a couple that I think are unrelated. May be transfer case related.

Heading to the dealer this afternoon. Should know by tomorrow what's up.

 

[8ball_99]

Yikes, I'll hook mine up to a flatbed with brakes and test mine. Rather find out now than when I need to tow.

 

[AXE]

Dropped it off at the dealer. Their code scanner showed many U codes, which are communication codes. Besides trailer connect/disconnect, truck seems to work just fine and no CELs.

I'm starting to think the OBD plug for the AMP steps might be throwing these codes. Install was exact same as 1500, but I got a CEL immediately after install when I reconnected the battery. Cleared it and it hasn't been back.

I guess I'll know by tomorrow.

 

[8ball_99]

Dropped it off at the dealer. Their code scanner showed many U codes, which are communication codes. Besides trailer connect/disconnect, truck seems to work just fine and no CELs.

I'm starting to think the OBD plug for the AMP steps might be throwing these codes. Install was exact same as 1500, but I got a CEL immediately after install when I reconnected the battery. Cleared it and it hasn't been back.

I guess I'll know by tomorrow.

You might be better off just tapping the wires directly into the BCM. If you look on gmupfitter and download the pdf. The BCM plugs stuff starts at page 7-311. Lol I was looking at it earlier and made a note of what page it starts at.

 

[AXE]

You might be better off just tapping the wires directly into the BCM. If you look on gmupfitter and download the pdf. The BCM plugs stuff starts at page 7-311. Lol I was looking at it earlier and made a note of what page it starts at.

Yeah, I'm gonna be pissed if I find out there's an AMP compatibility issue. I contacted AMP to confirm it was good. Some of the sellers website said it was compatibile, but a couple others didn't. Everthing seems to work fine with steps. We'll see!

 

[AXE]

Also messed with the emergency flashers on the way to the dealer. That issue may be more with the button itself. If I press the button on the front edge, they don't start flashing. If I push it towards the back of button, it'll start flashing everytime. More GM quirks I guess.

 

[AXE]

Dealer has a trailer simulator for testing trailering issues. They were not able to replicate the "trailer disconnect/connect" issue frequently popping up on my DIC. So I said "now what, take it to a urologist"?

I guess I need to do some more troubleshooting with my trailer to be sure it isn't the issue. I am gonna hook up my neighbors trailer and see if it happens again.

They were also not able to replicate emergency flasher issue. I figured out that the switch does not make contact if press the front of the button, but does if you touch the back of the button. Not a big concern now that I know what's happening. Not sure I'll have them yank apart the switch bezels, as that always seems to introduce more issues with poor fitting and cracked/broken tabs.