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Toolguy5's avatar
Toolguy5
Explorer III
Jun 12, 2025

2025 GMC sierra 1500 4x4 towed behind motorhome

Is anyone flat towing a 2025 GMC 1500 Sierra 4x4 behind motorhome.

Manual says the following

  1. Put transfer case in neutral and return to park.
  2. Put ignition in accessory mode
  3. disconnect battery ground.  

I see trailer sells a battery disconnect switch for battery put it is for the positive side. So my question is can this be utilized instead of disconnecting ground.

When battery is disconnected no power to vehicle. Will truck stay in accessory mode to be able to turn steering.

manual also says once transfer case in neutral vehicle can move in park. Does vehicle stay in park or does it need to be in neutral also.

i would like to set up to tow behind ma class A but want answers to the questions first.

from experience Rvers

Dan

6 Replies

  • I wouldn't use the switch on your ground or positive, I would just carry a 1/2" wrench in the truck and take 5 seconds and physically disconnect the ground from the battery.  if that switch fails while your driving you are kind of screwed, and like I said it take a few seconds to loosen a ground off.  

  • Based on the questions, I’d question your ability or experience to do this, but…
    To answer your questions, rather than ask the questions before even verifying what you’re asking, why not actually run the procedure and it will answer your questions. 
    PS, you don’t actually have to tow it down the road to verify what you’re asking. And as a side benefit, you’ll learn something rather than being told it and likely understanding less. 
    Also yes, trans in park is the right way for reasons mentioned above.  There is no magic to disconnecting the battery. Pick one or the other posts to disconnect. Neg is best for reasons you can look up. 
    Don’t be surprised when you have to redo any pre set electronic things. 
    Any universal battery disconnect that fits the battery post will work although new vehicles have cables generally routed “perfect” with little play and semi vehicle specific connections, so may have to move some stuff around or modify the battery connection. 

    • Toolguy5's avatar
      Toolguy5
      Explorer III

      Grit Dog

      What a real jerk you are. not just with this post but others you have replied to that I read after you replied to mine.

      You don't know me and you don't know my abilities. 

       

  • Dan, In the manual there are actually 13 steps in setting up your truck for towing 4 wheels down and 12 steps for disconnecting it. I would suggest you make a cheat sheet for both and keep it in the truck to refer to. Skipping any step could result in an expensive repair bill.

  • (1) There is no reason you can't use that switch on the ground side. Buy it, install it on ground at battery, and enjoy. You're welcome.

    (2) Vehicle MUST be in park and transfer case in neutral at all times while moving. I know a guy who failed to do that, left transmission in neutral as well, and his reward was needing a new transmission after the first such tow. The reason being that with the fluid couplings in torque converter (and elsewhere) there was just enough rotational force transferred to cause the transmission internals to rotate, albeit slowly, but without proper lube since the transmission fluid pump wasn't being rotated, that it burned up all the bearings in the transmission. Granted it wasn't a 2025 or a GMC, but the design of things and instructions were the same. 

    (3) And yes, the truck stays in ACC mode the whole trip to keep the steering from locking up.

    • Toolguy5's avatar
      Toolguy5
      Explorer III

      Thanks

      so with battery disconnected the truck will stay in ACC mode?

      I would have to look at battery switch again to see how it would get power if hooked to negative side.

      Dan