Power is Returned to 2015 Ford Edge with Negative Battery Cable Removed and Plugged into RV

Question:

I had a company install a Blue Ox towing system on my 2015 Ford Edge Titanium. The factory information says the negative terminal needs to be disconnected when towing. A switch was installed disconnecting the negative terminal. However, when the tow vehicle is connected for the lights to work the Ford Edge now has full power back on as if the negative terminal is back connected. Remote door locks now work and all other features appear to be back working. This also turns back on the odometer and the mileage is now recorded for all miles towed. I have also noted that when the vehicles are parked with all lights off and I use the remote door unlock the Ford Edges lights come on and in turn it also turns on the tail lights on the motor home. Question: Did the dealer use the wrong wiring kit? Wiring not done correctly? Or is this the correct way the wiring should work?

asked by: Paul M

Expert Reply:

First you should know that miles will accumulate on your 2015 Ford Edge whether it has power or not. But the vehicle having power when the negative cable is disconnected via a switch should not be happening. Are you certain it is a switch to remove battery power or is it a fuse bypass switch?

If it is a battery disconnect it might be # RM-766. If it is, or something similar, then the vehicle battery may still be getting a maintenance charge from the RV. But that still would not explain why all the electronics are working on the vehicle if the negative battery cable is disengaged. Something with that switch and the wiring from the RV to the Edge must not be installed correctly. I would take it to the place that installed it and explain the problem because something is not right.

If you can tell me what parts were used for this installation I can look to see how it should have all been installed and we can go from there.

expert reply by: Michael H

Greg P.

4/6/2020

In the Ford factory owners manual for a 2015 Ford Edge, it says to disconnect the negative battery cable while 4 down towing. The RM-766 roadmaster battery disconnect kit if for disconnecting the positive cable. Would this accomplish the same thing? Why does Ford recommend disconnecting the negative cable? Could the RM-766 kit be used for the negative cable as an alternative?

Chris R.

4/7/2020

You will want to follow Roadmaster's recommendation of disconnecting the positive cable when installing their Battery Disconnect. This has actually come up before (a lot of vehicle manufacturers point out the negative cable in the manual) and we have spoken with Roadmaster. Using the positive cable won't cause any issues and the reason a lot of manufacturer's recommend the negative is for safety/liability - they would just rather customers stay away from touching the power cable if possible.