Community Forums

dmctlc · 01-04-2022, 06:52 PM

So I looked through other post and couldn't find anything related to the issue I'm having so I wanted to post it. So we have a 2017 Lincoln MKX FWD that we tow behind our 2016 Tiffin Phaeton 44OH. I'm hoping to find someone with a similar model car and year to see how they have there's hooked up but I'm also looking for solutions to the problem I'm having right now.
Problem: This has happened on the 1/2 dozen trips this year, one being a 4000 mile+ trip to NE this summer and another 1800 Mile+ trip To TN, Ga., etc. and even a few weeks back to the Florida Keys which is about 250 miles. We arrived at the CG and unhooked the car, it started right up no issues. 7 days later drove back home unhooked the car, dead as a doornail, not even a click. Had to unlock the door with the key inside the FOB for the car. So I've attached some pictures of my setup which was done by a shop in Sarasota when they installed the Baseplate. Battery is fairly new and never have any issues starting it up. Checked for 12V from the MH and it's fine. I've replaced the shortstop 12v b24 20 a 12 auto-reset breaker to no avail. Worked once then the same issues again. Found Battery had boiled over some several times so obviously it's getting over charged. I'm wondering with all the electronics this car has including the adaptive steering it's calling for more current than the MH can supply or even the 20AMP Breaker or 10 guage wire. Check Voltage from MH to Breaker seems appropriate it but of course I can't check it while driving or the breaker engaged. My buddy has the same setup but with a different car and has no issues. Hence why I was looking for someone with a similar car and year as mine with something that works for them. Checked ground and no issues there. I'm fairly handy with my Fluke meter and electronics/electricity but I keep think I'm missing something, comes with age I guess. Btw the green wire is the 12v from the MH. The Red wire, was only a recent addition after the issue had started, it's suppying 12v power to the cigarette lighter I had to install under the dash since nothing stays on inside to supply power to my RVi3 Brake, the ground is directly to the chassis off to the left of the relay. One of the two black wires goes underneath to the back of the car the other can't seem to find where it's going so assumed it was going to ground someplace behind the battery. Tough to trace those two black wire. Perhaps one of them are the issue.

Windward · 01-04-2022, 08:47 PM

I had a similar problem towing an Equinox. This post has a lot of information useful to track down your problem. https://www.irv2.com/forums/f85/2013...ng-541683.html
NXR was very helpful explaining the details of what it takes to provide full charging to the toad.

My problem turned out to be a combination of weak links in the system that would not provide a constant 8 amps needed to the toad. Wire size (including the pigtail), wiring to the plugs on both ends, and I found the small round plug on the car end would not provide a reliable high current connection. I replaced it and the pigtail Roadmaster provided with the same large flat blade plug as the coach had and 12 ga pigtail not the 18 ga that Roadmaster used. And remember it is not just the positive wire but both positive and negative or ground wiring that makes a complete circuit.

I'm not sure why you could be over charging and boiling the toad battery yet have a dead battery at the end of your trip?? If it is really overcharging the entire trip that is a fire hazard and at a minimum shorten the battery life.

I agree all the electronic load on your car while towing puts a load on the coach charging system, but it should not boil the toad battery. Have you put an amp meter on the battery of the toad while it is in tow mode to see what the load is?

nctox · 01-05-2022, 06:16 AM

I had a similar problem with my 2016 MKX in the first year of towing it. After replacing the battery didn't solve the problem, I took it to a dealer. They ran some diagnostic tests and discovered a small drain on the electrical system, even when in the neutral towing mode. It was corrected and hasn't been a problem since.

dmctlc · 01-05-2022, 06:33 AM

Quote:

Originally Posted by nctox

I had a similar problem with my 2016 MKX in the first year of towing it. After replacing the battery didn't solve the problem, I took it to a dealer. They ran some diagnostic tests and discovered a small drain on the electrical system, even when in the neutral towing mode. It was corrected and hasn't been a problem since.

Do you happen to still have the work that might've explained what they did to test it and fix it as well?

nctox · 01-05-2022, 08:59 AM

Quote:

Originally Posted by dmctlc

Do you happen to still have the work that might've explained what they did to test it and fix it as well?

I'll check to see if the paperwork reflects the problem and what the fix was.

The tech called it a TCM update SSM477159.
Hope this helps.

Mr.Mark · 01-05-2022, 09:20 AM

I have a 2017 Lincoln MKX, AWD, that I pulled with my large coach. I still have the car. I've pulled it 23,000 miles and it has about 20,000 driving miles on the odometer.

I never had any issues. I put it in 'tow-mode' and off I went.

I'm now getting the Mini Cooper set-up for towing as it's much lighter for the 'Bee'.

I hope that you can locate the issue!

(My pic to the left is showing me pulling the MKX)

Safe travels,
Mark

dmctlc · 01-05-2022, 01:06 PM

Quote:

Originally Posted by nctox

I'll check to see if the paperwork reflects the problem and what the fix was.

The tech called it a TCM update SSM477159.
Hope this helps.

I'll take a look but usually TCM is refers to Transmission Control Module which I wouldn't think it would be related but who can tell with today's electronics in cars with Adaptive Steering, collision avoidance, BLISS, etc.
THanks for the info.

dmctlc · 01-05-2022, 01:07 PM

Quote:

Originally Posted by Mr.Mark

I have a 2017 Lincoln MKX, AWD, that I pulled with my large coach. I still have the car. I've pulled it 23,000 miles and it has about 20,000 driving miles on the odometer.

I never had any issues. I put it in 'tow-mode' and off I went.

I'm now getting the Mini Cooper set-up for towing as it's much lighter for the 'Bee'.

I hope that you can locate the issue!

(My pic to the left is showing me pulling the MKX)

Safe travels,
Mark

Was your 2017 MKX setup similar to mine with the 20Amp auto-reset breaker or something different. If different what was it you had? Thxs

dmctlc · 01-05-2022, 01:08 PM

I meant to mention that we shut down everything we can in the car including the AC and radio thinking it was drawing from those too much.

CoolTech · 01-05-2022, 01:20 PM

OP - you say you are pretty handy with the Fluke, so maybe you can connect it to the MKX battery and see what kind of current draw you are seeing. I'm not familiar with the Lincoln recommended towing steps, but I would assume that the MKX is towed with the ignition in the OFF position and then (theoretically) there is no current draw other than your aux braking system? Is this correct?

Anyway, with the Fluke in ammeter mode, you might be able to do some more detective work to narrow in on where the problem is. I guess there's two theories on what the problem may be??

1. The charging line from the MH to the Jeep is not working properly and the aux-braking device is depleting the battery

2. There is more than just the aux braking device drawing current in the MKX when it is set-up for tow and this draw is exceeding the charging capacity of the line from the MH.

Let us know what you find.

Mr.Mark · 01-05-2022, 05:06 PM

Quote:

Originally Posted by dmctlc

Was your 2017 MKX setup similar to mine with the 20Amp auto-reset breaker or something different. If different what was it you had? Thxs

I am not aware of any breaker. I never studied the set-up.

I'm at my home in California until the end of March so I won't see the MKX until I return to TN. (sorry).

Safe travel,
Mark

dmctlc · 01-06-2022, 06:32 AM

Quote:

Originally Posted by CoolTech

OP - you say you are pretty handy with the Fluke, so maybe you can connect it to the MKX battery and see what kind of current draw you are seeing. I'm not familiar with the Lincoln recommended towing steps, but I would assume that the MKX is towed with the ignition in the OFF position and then (theoretically) there is no current draw other than your aux braking system? Is this correct?

Anyway, with the Fluke in ammeter mode, you might be able to do some more detective work to narrow in on where the problem is. I guess there's two theories on what the problem may be??

1. The charging line from the MH to the Jeep is not working properly and the aux-braking device is depleting the battery

2. There is more than just the aux braking device drawing current in the MKX when it is set-up for tow and this draw is exceeding the charging capacity of the line from the MH.

Let us know what you find.

Good suggestions I'll take a look at that today. I agree with another comment that's puzzling me if the battery seems to be boiling over some yet ends up dead it just don't make sense to me. I'm also going to Jake the car up again take off the underbody shield lincoln has on their cars and track down those black wires. Something about the setup bothers me too. I got a buddy coming down for the week of the 17th going to the Tampa RV show. He has a similar setup on his Equinox that he tows I can see better how his is set up and take some readings to see what he has. Thxs

FLYING BUTCH · 01-07-2022, 07:28 AM

I pull a 2016 mkx. The battery will run down with everything turned off. I spliced a hotwire running from the coach going into the cars lighting system (off brake, tail, and turn signal wiring) and put a clip on the end of it. Run it through a diode and clamp onto battery. It will keep a little power coming from coach to cars battery. Sometimes if I pull for a long time the battery will still get weak.

CoolTech · 01-07-2022, 08:25 AM

Quote:

Originally Posted by FLYING BUTCH

I pull a 2016 mkx. The battery will run down with everything turned off.

What is it about the towing prep sequence that causes the MKX to start consuming power? Certainly it doesn't consume power just sitting in a parking lot... so something is getting turned on. Anybody have ideas on what is getting energized?