2013 Grand Cherokee toad and negative battery terminal

phoeg · 07-28-2018, 10:28 PM

I'm getting our 2016 Hurricane 34F and Jeep ready for its first big trip next Sunday. I was doing a dry run today hooking up the tow bar and learning the procedure for disengaging the Jeep transfer case. The Jeep manual (like some other cars) says to disconnect the negative battery terminal. I have no definitive answer yet as to why.

We have a Stay-In-Play Duo braking system, and part of that system has connections to keep the battery charged while towing in the RUN/ON position. If the disconnect has ONLY to do with not discharging the battery, I'm guessing this is not a necessary step. But...I don't know if there's anything else involved. It's too late on Saturday to call the Jeep or RV dealers, so I'm asking here for thoughts.

Thanks.

Paul

Ron1Z · 07-29-2018, 11:28 AM

I was hoping that you would get an ansewer, Im having the same issue after hooking up a new toad yesterday.

**16ACE27** · 07-29-2018, 01:33 PM

Do you have electric power steering? Is this one of the jeeps susceptible to the "death wobble"?

phoeg · 07-29-2018, 02:58 PM

Quote:

Originally Posted by Tfryman

Do you have electric power steering? Is this one of the jeeps susceptible to the "death wobble"?

To the first question: I just looked, and I could identify the alternator and water pump, and the serpentine belt drove another item (it's crowded in there) that had hydraulic lines attached. Given that those three items are usually drive by the serpentine belt I'm guessing no. I'll confirm with the dealer tomorrow.

"Death wobble"? And that would be? You can guess my answer is "I have no idea!" LOL I'm going to have to search for that term.

Thanks for those questions. They give me an idea of things to confirm "yea or nay." Ultimately, if I disconnect the negative and I don't have to I harm nothing.

RichS · 07-29-2018, 03:11 PM

I have a 2015 Jeep Cherokee. I have the wire harness to keep the drive system powered. There is nothing mentioned about disconnecting the negative battery cable for my Jeep. They say start the engine every three hours to charge the battery.

phoeg · 07-29-2018, 03:21 PM

Quote:

Originally Posted by rscheibel@cfl.rr.com

I have a 2015 Jeep Cherokee. I have the wire harness to keep the drive system powered. There is nothing mentioned about disconnecting the negative battery cable for my Jeep. They say start the engine every three hours to charge the battery.

When the dealer did my braking unit installation they had to add the wiring for the lights and I'm 99% sure there is a line to keep the battery charged. As for the drive system being powered? That I'm not sure of. I imagine if the battery is getting power to charge it then the rest of the system is getting power.

RichS · 07-29-2018, 03:37 PM

The wire harness is hot wired from the battery to the drive unit. When you need to use it you have to insert a 10 amp fuse in the line. If you do not do that I am sure you don't have that , it came around late 2014 because some Cherokee wheels would start to wobble when towing.

phoeg · 07-29-2018, 03:44 PM

Quote:

Originally Posted by rscheibel@cfl.rr.com

If you do not do that I am sure you don't have that , it came around late 2014 because some Cherokee wheels would start to wobble when towing.

I've heard nothing about that from either the RV dealer or the Jeep manual. Ours is a 2013, so likely came before the timeframe you mention.

Baddad53 · 07-29-2018, 04:41 PM

Jeep sells a harness for the Cherokee to tow four down. I installed a connection kit from the 7 pin harness (make sure you have power on that pin on your RV) to my battery (it has a diode in the unit) to charge the tow vehicle from the RV when connected. My Patriot braking system plugs into the 12v socket so it's using the jeep's battery.

phoeg · 07-29-2018, 04:50 PM

Quote:

Originally Posted by Baddad53

Jeep sells a harness for the Cherokee to tow four down. I installed a connection kit from the 7 pin harness (make sure you have power on that pin on your RV) to my battery (it has a diode in the unit) to charge the tow vehicle from the RV when connected. My Patriot braking system plugs into the 12v socket so it's using the jeep's battery.

That sounds like the setup on mine. The coach provides power to the braking unit and Jeep (they had me bring the coach to the dealer to test the connections. There's an 8-pin to 6-pin adapter cord that plugs into a socket on Jeep grill to power the braking unit, etc. The extra wiring had diodes in it I know. I'm just not well-versed on the finer points, but they installed that too. It's on the work order and invoice.

I'm going to check with both dealers tomorrow on all these items. I'm suspecting I won't need to disconnect the negative, but I want to be 100% sure.

Laco · 07-29-2018, 05:39 PM

On my Chevy HHR toad, you have to pull a fuse when its towed, which I have installed a switch for. Without doing that all the accessories are live, the SRS system is active and the odometer will register miles towed. Pulling that fuse disables all that. When I was looking for a toad, years ago, I stayed away from any of the Chrysler products, as the odometer continued to register while being towed. Do not know if that is still the case today or not, my info is about ten years old.

Baddad53 · 07-29-2018, 06:57 PM

My 2011 Wrangler does not show miles when towed. Of course with the transfer case in neutral how would it.

phoeg · 07-30-2018, 02:13 PM

The final answers:

The RV dealer said not to disconnect the negative as I'm getting power from the coach via the electrical hookup.

Per the Jeep dealer (where I sit typing this) 2013 Grand Cherokee has hydraulic power steering. All good there. They know of no reason to disconnect the negative terminal. My suspicion remains that Jeep includes that so you don't run down the battery. But…if you're connected to RV power with charge to the toad battery it's likely moot.

What an adventure this first RV!

Thank you all for the feedback.

Paul

gmc · 07-30-2018, 11:49 PM

My 2010 Wrangler says to disconnect the battery... Because the ground is used by the braking system - the installer placed the disconnect on the positive side - with only the braking system bypassing (which powers the braking system in breakaway event - and charges the toad battery.)
They seemed to feel I could tow either way.

The only difference I noted was with the battery connected, the third brake light (high center mount) lights while the toad brakes are actively engaged. (The invisibrake only engages the toad brakes for 30 seconds - then releases - so after having brakes applied for 30 seconds - the center light goes out.)
The third light is not powered at all if the battery is disconnected.

(The main Jeep brake lights are of course on anytime the RV brake pedal is depressed - provided by a Jeep OEM harness.)

While I haven't seen any other difference or issues - I tow with the battery disconnected anyway.

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