15 replies to this topic

[lylefikse]

We bought a new Lincoln MKS this year to tow.

We put a hot wire from the motorhome to the car battery to charge while towing. Works OK on short trips. Not so well on all day drives.

I forgot to put it in park after the first day and of course it was dead in the morning. Had it jumped and ran it for a brief time before setting out that next day. Dead again that night. Jumped again and ran it for two hours. Started right up the next morning before towing. Started it again when we stopped for lunch at noon. Then put on another 300 miles and it was dead we we arrived at night.

Ideas?

[hermanmullins]

Lyle,
Did you put a fusable link in the line from the coach to the Battery? If so is the fuse blown? What size wire did you run between the coach and battery? Too small and you may not be getting enough power. Do you have a auxilary braking system?

With out any thing on in the car disconnect the Positive cable and put a volt meter between the cable and post. If the meter reads 12 volts + with every thing off that indicates a draw on the battery. If there is a draw, remove one fuse at a time and replace it if the meter still reads 12 volts. When you pull a fuse and the meter drops to zero that is the circuit that has a draw. It could be something a simple as a glove box light that is on.
Hopes this helps you find the problem.

Herman

[lylefikse]

Thanks Herman. We do have the Air Force One Braking system. The one you have (Is it M and G?) would not fit on our car (not enough room). AF1 seems to work well. I had Leach Camper in Council Bluffs, Iowa install the air force one and at the same time put on the charging wire. It is a small wire. It comes off the wiring harness for the lights. I'll check for a blown fuse on the charging line.

[mrboyer]

We have the AirForce 1 braking system on a Chevrolet Equinox. On our first trip, I didn't pull a fuse and the battery was dead that night.

Since then I have replaced the fuse connector with two fuse taps and a switch to turn off this circuit, we have not had a dead battery. The fuse taps are available from your local auto supply store, but of course you have to determine which fuse circuit needs to be disconnected. Our owners manual indicated which one. On a previous towed, I had to do the process suggested above to find the right fuse.

Our owners manual also suggests that we run the engine at each fuel fill when towing. I don't think they mean 600 miles; therefore, I run the engine for 5 minutes and shift into drive and reverse a couple of times and then leave it in neutral at lunch and when we stop for the night. I do put in park and remove the key at night after running for the 5 minutes. I lay the tow key and the motor home ignition key on the dash of the motor home so I don't forget to setup the towed the next morning.

[lylefikse]

I am confused, what does the braking system leave on? I thought the battery drain was from the keyless ignition. This can't be turned off on the Lincoln. That is why I ran a charge wire to the battery.

[hermanmullins]

Lyle,

What you need is a wire from the Positive side of your Coach Battery to the Positive side of you vehicle Battery and it should have fuses at both batteries.

[lylefikse]

It is fused on the car side. Fuse is OK. Never thought of one on the motorhome side. I check for one tomorrow.

[WhiteEagle]

I had a dead battery once while towing the toad so decided that wouldn't happen again...
I bought a portable charger / booster / jump battery unit - ( same size as regular battery - available in different size amp power)
I use this for the brake unit power rather than the toads battery - brake unit plugs into it rather than toads 12V lighter socket.
Whenever we get to where we are going, I put it on charge... always have a charged unit for next day travel or if anyone else needs a battery jump.

[hermanmullins]

Lyle, Sorry I made a miss statement The charging wire only needs one fusable link.

Herman

[wolfe10]

Lyle, Sorry I made a miss statement The charging wire only needs one fusable link.

Herman

No, Herman, you were right the first time. There should be a fuse/fusable link at EACH positive battery terminal, since any contact with chassis/ground would create a dead short from either battery.

Brett

[larryrb]

I have a new 2013 Ford Explorer with the same keyless ignition. I have the hot wire from the MH plug connector wired to the hot side of the Explorer battery through a "toad charge". I have about 5000 miles towing the Explorer without problem. I do run the Explorer a couple of times a day if we are going to be traveling more than 6 or 8 hours but other than that no special precautions. First thing before traveling i run the engine for 10 minutes or so and then put the transmission in neutral after shifting through drive and reverse as required by ford. I then lock the doors using the door keypad, take the key with me and the the computer kills the electronics after 20 minutes (again as stated in the manual). I also have the AF1 braking system.

If you have a direct hot wire to the MH without the toad charge you can have a drain back to the MH when the rig is parked w/o either motor running depending on how the MH is wired. The tail lights on the toad can also be a drain on the battery depending on how it is wired.

i have never had a dead battery after installing the toad charge even after several days of towing in this manner. First trip out i did have a dead battery w/o the toad charge but only then after two long days of travel.

I would check to see if the hot wire from the MH is actually charging the battery on the toad.

[Knightrider]

We tow a MKX and were having same problem.. Found out from another owner who researched it from Ford and you have to put key in second position instead of first. Uses less power and no more problems, Turns off navigation and other running things....You don't need to pull a fuse .

We are having same problem with our new 2013 Explorer even though the book says nothing so we are towing the same way. We do not have keyless start.

Hope this helps Ours was a 2007 MKX

Ed n Peg Oswald
Lemont IL

[lylefikse]

300 miles today with no problem. I think once we got charged up all the way we were fine. Just need to remember to put it in park when we stop for the night. We ran it all the way down leaving it in netrual while parked overnight.

[lylefikse]

Update for anyone towing a keyless Lincoln. We have had no more problems. After charging up the dead battery and putting the car in park when not towing, everything works great. We have towed a few thousand miles with no more problems. Our one problem was operator error. 

[desertdeals69]

Make sure the charge wire is at least a #10.

[lylefikse]

Spoke too soon.  Dead battery twice when returning to Iowa from winter in Southern Calif.  Put a volt meter on it and it does not show any charge coming from motorhome.  Fuse on car side is OK.  Still trying to check the Motorhome side.  Update to follow.