So this thread has been dead for awhile but I managed to find a solution to Switchbacks causing a Short to Ground with the BCM.

Came across it today on the powerstroke forums while bored at work. The solution was simple enough I'm surprised I didn't think of it.

The rear-turn signal circuits are NOT protected by the BCM. So essentially, unless you got the relay solution to work (I honestly never got around to trying it) all you need to do is run a wire from the yellow(or w/e color) switchback wire to the tails, and tap into the turn signal wire in the back.

Just finished this up and now my switchbacks are FINALLY working as intended. Kind of a PITA running wires along the frame when this should just work in the front, but I'm just happy they're working now.

Will keep monitoring them, but for now no codes in ForScan and the circuit isn't cutting power.

 

Great solution.

 

I'm going to remember that when I get to a similar setup.

 

How would tapping the rear turn signal not trip the BCM? When the rear bulb is out, the BCM still triggers hyperflash.

 

The relay solution does indeed work. I provided the harness and diagram to ecobeast himself. It is also the same solution I used for my headlight build.
The fault can be an over current that the BCM is detecting outside its normal range. In my case, the amber lights in addition with the turn signal were drawing over an amp more current then the BCM is used to seeing. The relays take the current off the turn signal circuit and my truck has been fine since.

 

I think he is referring to the rear not being protected by the overcurrent condition. But you can still get the hyper flashing if the current too low.

 

I think I burned my BCM out from all the short circuits due to my switch backs. Would anyone be willing to help with replacing that and wiring up a relay?

 

Have you reset the BCM at all yet? If not, I would apply the relay fix and reset the BCM. It is only after many resets does the BCM no longer reset and require a replacement.
I would not be opposed to making a few harnesses with relays installed if enough interest is there. Can include everything needed for a simple install.

 

Thanks! Yeah I have reset it many times, and have since removed my switch backs from the OEM turn signal harness. I have codes U3000.49 and U1000 along with both fron turn signal short circuit codes. I have run BCM tests with everything uninstalled and nothing has fixed the issue, and I still have those codes.

 

Yea, you will need a BCM replacement. Think a new one runs $160 or something. You can not replace it yourself as you will need the Ford software to program the BCM.
The dealer should not charge you more than an hour to replace it and program it as a competent technician should only take an half an hour.
You will also need both keys with the truck.