lylefikse

Dead Battery On Lincoln MKS

26 posts in this topic

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?

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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

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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.

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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.

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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.

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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.

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

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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.

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

Herman

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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

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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.

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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

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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.

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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.

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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.

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We were at our FMCA Chapter (Heartland Travelers) rally last month at Blue OX in Pender NE. What a great time they showed us. Free inspections and repairs of tow bars and a great full hook-up campground. While inspecting our unit they discovered that they person we had install our brake system failed to connect our charge line from the motorhome to the car. It was on the wrong post. A ten minute repair. Also done free by the Blue Ox support team. Hope our dead battery issue is solved. Thanks Blue Ox!

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I have read this thread from the beginning. I'm hoping my new purchased 2013 MKX will not be a problem.

I have the electronic keyless system. I have read, (besides the shifting and starting for 5 minutes before and every fuel stop) to press the electronic keyless button once to place the system in "accessory" mode, shift into neutral an away we go.

Question: After 20 minutes the electronic system shuts down. Where would a drain on the batteries be coming from?

Is there any fuse that could be pulled to alleviate this problem?

I'm going to look into a "toad charge."

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We bought a 2012 Lincoln MKX last year when we bought a new Marathon XL4s. It has been nothing but frustration. We've had the factory look at it as well as four Ford dealers. It is a keyless system also. The book says to put it in neutral, hit the button to turn the car off and then hit the button twice until you see "accessory mode active". We've done that as well as make sure the radio and climate controls are off. We still have a dead battery unless we start it every 3 hours. We've even disconnected the power cord from the coach in case it's the bus. Still had a dead battery. It doesn't have an independent braking system and I use a Blue Ox towing bar. When we bought the car, we had an RV dealer put the necessary wiring on it to keep it charging while driving down the road. I'm about ready to get another vehicle!!

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Drambo,

Welcome to FMCA!

You mentioned that you had the RV dealer install the circuit(s) needed to keep the battery charged.

When you have the car connected to the coach, open the car hood and measure the battery voltage. Then start the coach, the battery voltage should read around 13 to 13.5 volts when measured across the positive and negative terminals, if not then the charging circuit the dealer installed id not working.

Let the group know what you find and post your findings.

Rich.

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I thought I had a charge line too and it was not hooked up properly. Have it rechecked to make sure it is on the same post on the car and MH.

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Towed the 2013 Lincoln MKX for the first time last week for 240 miles. I don't think there is any difference in the procedure so here is what I did.

Hooked up, of course. After putting the keyless start into the accessory position, I turned off the radio and the AC then the display. I shifted into neutral in the proper sequence as indicted in the manual. Exited the car and towed. Four hours later there was no problem with the battery.

I typically only travel 250 or so miles a day and we usually stop in a rest area or truck stop for lunch. On this trip we travelled straight through with no stops. When I do stop for lunch in the future I'll start the car and let it run for 5 minutes as the book indicates, then repeat my procedure for towing. If it ever acts differently than this first time, I'll post the information.

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I might be over cautious but when I installed the charge wire for our toad we were towing a 10 Equinox I installed a diode on the battery wire to battery to stop any feed back to the coach also fusible link at the coach and toad battery and used #10 Wire. So far we have used this on the 10 Equinox, 11 Edge and 13 F150 4X4 no problems since the installation, cost would be about $25 to $30 I had everything but one fusible link in my shop so price could be more.

Walt

2000 Dyn

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Walt,

Totally agree, it is critical to have a fuse at both chassis and toad battery.

But, diodes generally "cost" over half a volt drop-- a lot when you are charging.

I prefer to use an "ignition hot" signal on a 40 amp RELAY. No voltage drop, and as soon as the coach ignition is off, the two batteries are separated.

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