2014 Ford Focus Battery disconnect

[stepside454]

Originally Posted by hdmoxness

I just bought a new tow car, a 2014 Ford Focus Hatchback. Besides having all the nice bells and whistles that we wanted in the Titanium, it has a 6-speed automatic transmission that does not have a torque converter and all the associated hydraulic technology. Instead, it is basically a manual transmission with two electronically controlled clutches—in other words, a computer-controlled manual. I was tired of shifting that 1999 Saturn 5-speed, lol.

So to tow this car, you “trick” the thing into Neutral (per the owner’s manual), then remove all electricity from the car so it can’t possibly engage a clutch or put itself in gear. You know what that would do while under tow! The key to this is, per the Ford manual, to “remove the negative (black) cable” from the battery. If you choose some alternate method, you may subject yourself to unwanted fault codes and need to reprogram some computer-related things each time, nevermind turning the tranny into a blob of melted metal. The down side to this car is the battery position under the hood in front of the driver. There are two covers that snap on over the top; the one nearest the front comes off easily and reveals the positive end of the battery. The back cover is harder to get off (and put back on) because it is tucked under the base of the windshield with not very much room above. Once it is off, you can barely see the negative battery post and cable connection, let alone get a tool and your hands in there. So I’d like to share some tips and a couple of solutions to make this an easy changeover.

As a side note, I would like to add that I installed a Blue Ox baseplate, readily available for this car, and I used a BO taillight wiring kit that does not interact in any way with the factory Ford wiring. One hole was drilled in each of the taillight housings for a lamp socket and the flat 4-color wire cable runs forward to the plug at the front grill. No diodes, no splices, no chance of putting 12V into the Ford that could accidentally activate anything in the transmission!

Before doing anything with the battery, I viewed an excellent video on YouTube which tells you how to remove the covers, retainer, and battery; this write-up presumes you have viewed it, too. You don’t have to remove the battery to get at the negative post in the back, but to release the front of the battery box and pull the battery slightly up and toward you gives you better access. The negative cable end (pictured here) is a complicated battery post clamp with some add-ons including two little wires in a ribbed cable protector that go somewhere unknown.
Attachment 54004 Attachment 54005
After it is off and pulled out into the open on top of the fuse box, you need a 2-gauge 15” top post battery cable (such as a Duralast GT215B at Autozone $8); it has a post clamp on one end and a terminal lug on the other end. Position it on the negative post with the cable exiting toward the rear of the car; you will be able to get a ¼” drive ½” hex socket wrench on the nut to gently tighten it. Route the cable forward and toward the driver’s side through the notch in the top of the side of the battery box and forward out into the open. Secure a conversion post (such as a Lynx 07047 at Autozone $3) to the cable terminal lug using a 3/8-16 x 3/4” bolt and washer. Now you have the battery’s negative post and the complicated negative cable clamp lying on top of the fuse box where they can easily be joined or separated for towing. End of solution 1.
Attachment 54006 Attachment 54007
Solution 2.0: Remove the conversion post from the negative cable; connect the freed terminal lug to one terminal bolt on a battery disconnect switch (such as a Battery Doctor rotary battery switch, about $30 online). Make up a short 2-gauge cable with a terminal lug on both ends; I used another Duralast GT215B, cut off the post clamp and a bunch of cable, and crimped another 2-gauge lug on so that the terminal holes were about 4-1/4” apart. Put the conversion post on one end and connect the other end to the disconnect switch. With the switch OFF, put the complicated connector on the post and gently tighten it. Now you can use the switch to remove or replace the negative cable on the battery. See pictures and good luck.
Attachment 54008 Attachment 54009

Remember to start the engine within 15 minutes of reconnecting the negative cable to the battery!

I did 2 with the switch , easy pesy , thanks for the tip

[f14av8r]

Great tips but a lot of unnecessary work in my opinion. I simply disconnected the positive cable (easy to reach) and tucked it into the front of the battery compartment. That worked well for many towing miles. I never had to reprogram any computers when reconnecting the power.

Running a separate wiring harness for independent bulbs is a must and I used that approach as well.

[stepside454]

It really wasn't a lot of work . Once I had the pieces gathered up it took about an hour .

[aquestrian]

We recently downsized from a Class A to a Class C 31ft Winnebago which we found out was not a happy camper pulling a Ford Flex. So in replacing our second car we bought a 2-16 Focus Hatchback, Titanium , pushbutton start and all the extras. We stayed with Roadmaster base plate to match the flex tow bar, separate lighting wiring, and the Brake Buddy, brake a way switch. I have read all the various post about the battery disconnect and had questions.


I called Ford Motor Company direct, and Owner Relations double checked with Engineering and told me the Only reason for listing disconnecting the battery is to avoid battery drain. They, my local Dealer, and the RV tech that did the installations all said the charge line from the RV will negate the draw down.


Am I missing something?

[JoeCar]

Originally Posted by aquestrian

We recently downsized from a Class A to a Class C 31ft Winnebago which we found out was not a happy camper pulling a Ford Flex. So in replacing our second car we bought a 2-16 Focus Hatchback, Titanium , pushbutton start and all the extras. We stayed with Roadmaster base plate to match the flex tow bar, separate lighting wiring, and the Brake Buddy, brake a way switch. I have read all the various post about the battery disconnect and had questions.


I called Ford Motor Company direct, and Owner Relations double checked with Engineering and told me the Only reason for listing disconnecting the battery is to avoid battery drain. They, my local Dealer, and the RV tech that did the installations all said the charge line from the RV will negate the draw down.


Am I missing something?

Yes. The current generation Ford Focus has been available with several transmissions. For automatics, this generation (2012-2017) has had two types of automatics, a conventional torque converter transmission and a Dual Clutch Transmission (DCT) – also called Automated Manual transmission by the government. The DCT does not really have a “neutral” like the torque converter or manual transmissions. When in “neutral”, one transmission is in reverse and the other transmission is in first gear. The gears are selected electrically via the transmission control unit. There are many posts available about what happens when a stray electrical current selects reverse or 1st gear when being towed 65MPH (or even slower) behind a motorhome.

The rationale for disconnecting the negative is simply a safety issue. Whenever changing a battery, it is always recommended to remove the negative side first. Earlier posts in this thread and another Focus towing thread on this forum details some folks that installed a built in supplemental breaking unit that allows a stray ground by the way it ties into the brake lights, thus requiring a positive disconnect approach.

[aquestrian]

I have a brake buddy and added separated lights to tail light housing by passing the cars wiring. Kind of confusing reading all the post saying different things and Ford telling me another.

[stepside454]

Originally Posted by JoeCar

Yes. The current generation Ford Focus has been available with several transmissions. For automatics, this generation (2012-2017) has had two types of automatics, a conventional torque converter transmission and a Dual Clutch Transmission (DCT) – also called Automated Manual transmission by the government. The DCT does not really have a “neutral” like the torque converter or manual transmissions. When in “neutral”, one transmission is in reverse and the other transmission is in first gear. The gears are selected electrically via the transmission control unit. There are many posts available about what happens when a stray electrical current selects reverse or 1st gear when being towed 65MPH (or even slower) behind a motorhome.

The rationale for disconnecting the negative is simply a safety issue. Whenever changing a battery, it is always recommended to remove the negative side first. Earlier posts in this thread and another Focus towing thread on this forum details some folks that installed a built in supplemental breaking unit that allows a stray ground by the way it ties into the brake lights, thus requiring a positive disconnect approach.

Might want to add this to avoid , or possibly create more confusion . The DCT transmission is essentially two 3 speed manual transmission , this may explain when he was talking about 1 transmission being in first & the other in reverse .

[stepside454]

E trailer has a battery isolated kit with a relay for focus that would allow you to use brake buddy

[JoeCar]

Originally Posted by stepside454

Might want to add this to avoid , or possibly create more confusion . The DCT transmission is essentially two 3 speed manual transmission , this may explain when he was talking about 1 transmission being in first & the other in reverse .

Thanks for filling that in, my post could be confusing. If anyone wants to see a great video of how a DCT works, here's one:

https://www.youtube.com/watch?v=lFAtc-zOKZs&t=278s

Note that some DCT transmissions have the two "transmissions" side by side, while other have them inline like this video.

Here's a video of the Getrag unit in the Focus, it is a compact side-by-side unit:

https://www.youtube.com/watch?v=K7Q2M2K0V5k

[Phochief]

2017 Ford Focus, auto, 2.0L, Titanium.......I've ordered the roadmaster diode tail light wiring harness, but have seen a couple of posts about diodes failing, which could let current pass through the Focus's wiring to the transmission, causing catastrophic problems.

My other option is drilling holes for bulbs that go inside the tail light housing.

Is diode failure a documented event that has killed multiple Focus transmissions? Should I run away from the diode tail light wiring harness?

I realize the other option completely isolates the vehicle wiring, but I don't like the idea of drilling holes in the tail light to accommodate secondary bulbs that are not centered behind the reflector and probably don't provide as much brightness as the OEM bulbs do.

Has your diode wiring harness failed? Do you know of anyone who had a diode fail and what the outcome was to their Focus tranny?

Thanks,
David

[c_oneil]

I think diodes will also defeat the cars CAN bus feedback system that tells you if a tail light is out. Maybe someone with diodes installed can confirm this here. Another thing diodes will do is give you a smal voltage drop and dim the lights a bit. Drilling new holes makes for dimmed lights also because the tail light housings are designed to reflect best from the original bulb position. I didn't use diodes or drill into the lens housings. I installed a couple switches that splice into the existing light circuits. When in one position it just passes the original circuits thru to the tail light sockets as designed and in the other switch position it opens the original circuits and connects the tail light sockets to the towing light wires. No chance of any current back feed and maximized brightness. Its a litte more work to solder in the switches and you have to flip the switches every time you tow but when you are retired your time is free.

[f14av8r]

David,
I recommend installing the separate bulbs. Electrically isolating the Focus from the motorhome is a very good idea. With the separate bulbs, you don't violate the integrity of your cars wiring at all. Installing the separate harness is easy. Just run it under the floor trim. Penetrating the firewall is the hardest part.

Installing the bulbs is fairly simple. The entire taillight assembly comes off very easily. Use a step drill to get clean, precisely sized holes. Mount or have someone hold the taillight assembly and drill the holes vertically from underneath the housing. That way the plastic chips will be easier to remove from the inside of the housing. A small, flexible hose attached to a vacuum cleaner works well too.

Best of luck whatever you decide. The Focus is a great car to tow. Thanks to the dual-clutch transmission, it's one of the very few automatic transmissions that you can completely disconnect from the drivetrain.

Randy

[Phochief]

Originally Posted by f14av8r

David,
I recommend installing the separate bulbs. Electrically isolating the Focus from the motorhome is a very good idea. With the separate bulbs, you don't violate the integrity of your cars wiring at all. Installing the separate harness is easy. Just run it under the floor trim. Penetrating the firewall is the hardest part.

Installing the bulbs is fairly simple. The entire taillight assembly comes off very easily. Use a step drill to get clean, precisely sized holes. Mount or have someone hold the taillight assembly and drill the holes vertically from underneath the housing. That way the plastic chips will be easier to remove from the inside of the housing. A small, flexible hose attached to a vacuum cleaner works well too.

Best of luck whatever you decide. The Focus is a great car to tow. Thanks to the dual-clutch transmission, it's one of the very few automatic transmissions that you can completely disconnect from the drivetrain.

Randy

After reading about the potential consequences of a diode failure I've decided not to go that route, and to go with separate bulbs. Since the bulbs used in the Roadmaster harness look pretty standard, I wonder if it might be a good idea to replace those tungsten bulbs with much brighter LED bulbs? Just a thought.

Thanks,
David

[stepside454]

We just towed ours for the first time this weekend from St. Louis to Terre Haute, worked great