Moisture causing short in battery junction box 207 police interceptor

[Oneyedjax]

So, about a month ago I was driving my Petunia, a 2017 (correction from title) Police Interceptor Sedan (3.5l TT Ecoboost; AWD ) in the rain and all of the warning lights came on on the dash. Got it home, restarted and all good. Then it happened again yesterday during an automatic car wash, all lights came on and this time when I pulled into vacuum space and turned her off she wouldn’t start again. I had to take the starter relay out of the battery junction box and suck any moisture (which I did not see, btw, any visible signs of moisture) out of it and then replaced and it started up fine no issues. Then today on my way to work in the 8 degree F weather and a ton of snow ice and slush all the lights came on again. Parked at work, came out at lunch and she started right up no warning lights or anything. I’m assuming this is water getting under the hood into the BJB, but don’t know where to start to fix it. My windshield seal is in need of fixing but never have any water in the floorboards inside so not sure if this is an issue related or not. Help me please! I’m a broke gal, and have to fix this myself. Thankfully I am a bit handy and do all work including oil changes and tire maintenance myself so far. I do own a copy of a tear down/repair manual but not a Ford branded one and cannot find any reference to this as a troubleshooting issue in that. Any help will be much appreciated. Thanks!!!

 

[Texas Marauder]

The BCM (Body Control Module) is in the LH footwell behind the park brake. If you have a leaking windshield water can leak onto and into the BCM. That will cause all kinds of strange behavior. Check carefully for water leaking onto the BCM.

 

[Oneyedjax]

The BCM (Body Control Module) is in the LH footwell behind the park brake. If you have a leaking windshield water can leak onto and into the BCM. That will cause all kinds of strange behavior. Check carefully for water leaking onto the BCM.

I have had to get to the BCM when I installed my stereo, so I know where that is located, although I’ve never had any moisture in the floorboards inside of her, but will definitely check it for corrosion or moisture. Unfortunately I don’t have a garage or anywhere that isn’t outside in the horrible weather (6” of snow)right now, so I’m going to buy some dialectic grease and put a tiny dab on the prongs of the relays and hope that keeps her dry until I can get somewhere dry to find the leak. Thanks for the advice!

 

[Texas Marauder]

IMHO, it is a mistake to put dielectric grease on electrical terminals. Dielectric grease is used to prevent the transfer of electricity. I know people do it all the time, thinking it helps. Use it on the seals of sealed connectors, but not on the metal terminals. All IMHO.