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gwjohnson

Towed Vehicle Battery Drain

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We recently picked up our new 2010 Tiffin Phaeton 40 ft diesel pusher. Driving it home towing our 2000 Chevy Tahoe, the Tahoe's battery was drained. We followed the Tahoe's manual instructions explicitly for towing it 4 wheels down, removing the 10 amp fuse marked "ING 0" (PRND21 Display, Odometer, VCM/PCM). The fuse has to be pulled to not drain the battery, since the ignition switch on the steering column has to be in the "on" position to unlock the steering wheel. Not only was the Tahoe's battery discharged, but the odometer still racked up miles on the 4 hour trip home. The dealer installed a Blue Ox Aventa 10,000 lb tow bar and used totally separate wiring for the towed vehicle running all the way back to the Tahoe's taillights, including separate bulbs. So, the battery drain can't be from the brakes, lights, turn signals, etc., since they're hooked directly to the motorcoach with totally separate wiring. The dealer also installed a Blue Ox Patriot electric brake system in the Tahoe. The only 12v connection from the Tahoe to the Patriot brake system is for a 'back-up' charge to the internal battery of the brake system. Has anyone else experienced a battery drain on their towed GM vehicle when the directed fuse has been pulled? Also, anyone experience the towed vehicle with an electronic odometer, still registering increasing mileage when towed, even with the fuse pulled? There are 2 other fuses in the Tahoe fuse box labeled "IGN 1" (Ignition, Instrument Panel) and "IGN 3" (Ignition, Power Seats) according to the manual schematic. Even though the manual doesn't reference pulling these fuses as well, I'm wondering if that would fix the problem the next time I tow the Tahoe. Any assistance / solutions, would be appreciated. Thanks.

GWJohnson
new member 2010

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Hi gwjohnson,

Gut feel says the installer made an incorrect connection. There are too many possibilities to list here. Consider taking the coach back to where the installation was done. I have experienced the toad battery being drained, but not the other problem(s). I tow a GMC ENVOY. I do not need to pull any fuses. The ignition switch stayrs off.

To keep the battery charged, consider this product: http://www.lslproducts.com/ToadChargePage.html. This is what I installed on my ENVOY and have had no additional battery problems.

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I ended these issues, towing our Jeep, by installing a simple blade switch on one of the battery posts. 2 seconds to flip, no fuses to pull, and no question about any power drain.

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I ended these issues, towing our Jeep, by installing a simple blade switch on one of the battery posts. 2 seconds to flip, no fuses to pull, and no question about any power drain.

Sorry JMonroe, when you open the connection on the battery you also delete your computer codes. It takes time to reset the codes, sometimes 100 miles.

The 2000 Tohoe doesn't have a streeing wheel locking pin [at least my 2002 doesn't have one]. The odometer racks up miles with the key on.

My toad is a 2003 GMC Yukon 4X4. Blue ox tow Bar, M. G. Brake [air brake]. When leaving I hook up Yukon to tow bar, plug in the lights, plug in air line, connect brake away lanyard and put Yukon in neutral and trans in park. I then move coach to make sure Yukon is in neutral and all lights work. I then remove the key, lock the Yukon and go RVing. Hope this helps everyone.

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Interesting. Did you pull the brake light fuse? Even though the towed vehicle wiring is not connected directly to the coach, if you are using a braking system in the toad then the brake lights will come on when the brake peddle is depressed.

Those fuses are really confusing sometimes. Are you sure you pulled the right fuse? I know I have done that a couple times. Depending on where it is you have to almost stand on your head to get to them.

Good Luck.

David

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GW, is it possible the ignition was in the "run" position and not the accessory position?

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Interesting. Did you pull the brake light fuse? Even though the towed vehicle wiring is not connected directly to the coach, if you are using a braking system in the toad then the brake lights will come on when the brake peddle is depressed.

Those fuses are really confusing sometimes. Are you sure you pulled the right fuse? I know I have done that a couple times. Depending on where it is you have to almost stand on your head to get to them.

Good Luck.

David

Thanks, David. No, I did not pull the brake light fuse, nor should I have to according to the Tahoe manual. However, there is totally separate wiring from the coach to the Tahoe, including new & separate bulbs drilled and placed into the brake light housing (separate bulbs from the Tahoe's original bulb sockets). Even if the Tahoe's brake lights do come on when the Coach's brakes are applied, no more than the few seconds that the bulbs would be lit during braking in the 2 hour Interstate trip, that wouldn't have been enough to drain the battery. I'll keep searching. Thanks for your ideas.

Greg

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GW, is it possible the ignition was in the "run" position and not the accessory position?

David,

The ignition switch with the key in the Tahoe HAS TO BE IN THE "RUN" POSITION TO UNLOCK THE STEERING COLUMN while towing (just like the instructions in the Tahoe manual under 'towing' instuct. The "accessory" position does NOT unlock the steering.

Greg

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Sorry JMonroe, when you open the connection on the battery you also delete your computer codes. It takes time to reset the codes, sometimes 100 miles.

The 2000 Tohoe doesn't have a streeing wheel locking pin [at least my 2002 doesn't have one]. The odometer racks up miles with the key on.

My toad is a 2003 GMC Yukon 4X4. Blue ox tow Bar, M. G. Brake [air brake]. When leaving I hook up Yukon to tow bar, plug in the lights, plug in air line, connect brake away lanyard and put Yukon in neutral and trans in park. I then move coach to make sure Yukon is in neutral and all lights work. I then remove the key, lock the Yukon and go RVing. Hope this helps everyone.

You are CORRECT about disconnecting the battery. Not only would that mess up the computer codes, but that would also prevent any 12 volt electricty needed through the cigarette lighter receptacle needed for the portable Patriot braking system battery back-up, which needs to be plugged in.

It's interesting that your 2003 GMC Yukon 4X4, nor your reference to your 2002 Tahoe NOT having a steering wheel LOCKING PIN. Unfortunately, my 2000 Tahoe 4X4 DOES HAVE A STEERING WHEEL LOCKING PIN. The steering wheel can ONLY be unlocked when the ignition key position is turned to "RUN" to unlock the steering wheel for towing. Perhaps they modified the steering lock in models after 2000, but that would surprise me.

Greg

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Hi gwjohnson,

In addition to the suggestion in my previous post, consider giving your local dealer an hour's labor and have them remove the pin. I'm not sure when GM changed or why they changed, but our 02 Caddy and our 05 GMC ENVOY have no locking pins in the steering column.

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So what's the 'downside' of "eliminating the computer codes"? I've never noticed any adverse affects. My home computer, nor my laptop, lose any of their programing when power is interupted. It was also claimed that I'd lose all of my radio presets - I do not.

As for losing power to the 12V power recepticles, when the battery is disconnected, that is right. That is also why I wired one of them into my towing / wire harness, it's now powered when plugged into the MH, ignition on.

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We recently picked up our new 2010 Tiffin Phaeton 40 ft diesel pusher. Driving it home towing our 2000 Chevy Tahoe, the Tahoe's battery was drained. We followed the Tahoe's manual instructions explicitly for towing it 4 wheels down, removing the 10 amp fuse marked "ING 0" (PRND21 Display, Odometer, VCM/PCM). The fuse has to be pulled to not drain the battery, since the ignition switch on the steering column has to be in the "on" position to unlock the steering wheel. Not only was the Tahoe's battery discharged, but the odometer still racked up miles on the 4 hour trip home. The dealer installed a Blue Ox Aventa 10,000 lb tow bar and used totally separate wiring for the towed vehicle running all the way back to the Tahoe's taillights, including separate bulbs. So, the battery drain can't be from the brakes, lights, turn signals, etc., since they're hooked directly to the motorcoach with totally separate wiring. The dealer also installed a Blue Ox Patriot electric brake system in the Tahoe. The only 12v connection from the Tahoe to the Patriot brake system is for a 'back-up' charge to the internal battery of the brake system. Has anyone else experienced a battery drain on their towed GM vehicle when the directed fuse has been pulled? Also, anyone experience the towed vehicle with an electronic odometer, still registering increasing mileage when towed, even with the fuse pulled? There are 2 other fuses in the Tahoe fuse box labeled "IGN 1" (Ignition, Instrument Panel) and "IGN 3" (Ignition, Power Seats) according to the manual schematic. Even though the manual doesn't reference pulling these fuses as well, I'm wondering if that would fix the problem the next time I tow the Tahoe. Any assistance / solutions, would be appreciated. Thanks.

GWJohnson

new member 2010

GW, it seems [in my openion] your did everything right with the exception of the brake system. I have spoken several times about the MG Air brake unit: http://www.m-gengineering.com/

Knowing what I know now, after several mistakes, I would do the following:

1) Tow Bar, you have a good one.

2) Lights, the dealer did a good job by wiring your light with diodes and direct connections to the coach.

3) Steering wheel, Go to your local mechanic and have him remove the steering wheel locking pin.

4) Braking system, see if your dealer will replace the Blue Ox brake with a MG. The MG has no electrical hookups. one air line and safety cord and your are hooked up. And you don't have to move it every time you want to tow or drive.

By the way Congratulations on your new coach.

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I'll second the installation error. We had a Unified Gear brake installed (Great system) but the installer NEVER connected us to 12 volts. Battery would go dead after about 5-10 hours depending upon the amount I used the brakes. Found out on a trip to Tulsa from NJ. Verified the correct terminals and added a lead to the plug from a dedicated 12v source. Been flawless ever since.

For the record, my unit was a 2007 Sunstar and the plug was not fully wired from the factory, no excuse. though. My new rig is 2009 Sunova, I moved the controller myself. The plug on this rig is fully pre-wired including the 12 v power.

Towing my Liberty, two items, trans is in park, transfer case is in neutral. Key is off, the wheel in this rig does not lock.

Good Luck

Jim

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We suffered battery drain on our Chevy Cobalt--I inadvertantly left the headlights on. Be sure the A/C, headlights, radio, etc are off before towing. We've had no further problems since I became more observant of the correct pre-tow check list. Good luck!!

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Hi gwjohnson,

In addition to the suggestion in my previous post, consider giving your local dealer an hour's labor and have them remove the pin. I'm not sure when GM changed or why they changed, but our 02 Caddy and our 05 GMC ENVOY have no locking pins in the steering column.

Gary,

Thanks for the suggestion about having the steering wheel lock pin removed. I had this done yesterday by my favorite GM mechanic. Now, I don't have to leave the key in the ignition to unlock the steering wheel when towing and an added benefit is that I no longer have to remove one of the fuses for the electronic odometer, etc. Now, all I have to do is hook up the tow bar & lights, without the ignition key in the Tahoe. Great suggestion. My mechanic did the steering pin lock removal on my 2000 Tahoe for $ 80. Thanks again for the great suggestion.

Greg

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Coach is a 2008 Phaeton 40' with a 360hp Mercedes .

We are getting ready to tow a 2008 Tahoe.

Also we will tow a 18' John boat behind the Tahoe.

Any info appreciated .

Can anyone can tell me what I need and what do I do?

Thanks.

Mike.

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Another easy solution to prevent any 12V battery drain because of a 12V power source required by a brake system is to use a portable 12V battery booster unit.... can be gotten from anywhere in several sizes, just set on towed floor, charge back up when on shore power.. will have available to start others whose batteries were drained while towing.

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Have been towing 2008 Jeep Wrangler over four years I installed a battery disconnect switch same effect as JMonroe no problems only have to reset clock and radio, have had Jeep at dealer for service they run computer checks and have never mentioned any problems,the dealer installed the last disconnect switch.

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