Wild electrical issue...

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Oct 17, 2021 | 02:37 PM

Ghost2017

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Wild electrical issue...

2018 F250 Lariat 6.7... yesterday something odd starting happening. When I press my brakes, after about 5 seconds all my HVAC buttons loose electrical power, the passenger airbag on/off light goes off, airbag light comes on the dash, and my driver side headlight comes on... when I release the brakes, after 5 seconds or so all my power comes back. I'm assuming this is an issue with the braking/abs system? I tried swapping similar relays in fuse box with no change. Anybody else has this issue? Sucks everytime I come to a red-light and have no AC! Lol. Truck has 33k miles on it currently.

Oct 17, 2021 | 03:44 PM

Phoenixfla

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I would start with checking the battery. How old is it? Voltage may be dropping on deceleration?

Oct 17, 2021 | 04:09 PM

Ghost2017

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Quote:

Originally Posted by Phoenixfla

I would start with checking the battery. How old is it? Voltage may be dropping on deceleration?

truck is a 2018, so batts are 3 years old. I just drove it now not doing as much. Now when hit my brakes it's just turning my driver headlight on, throwing the airbag light up on the dash and sometimes I can hear clicking under the passenger seat and my seat fans for the cooled seats turn off. The hvac panel is now staying on... for now. Both batteries have 12.7 volts. The driver side battery is red in the sight glass while the passenger side battery is green in the site glass...

Last edited by Ghost2017; Oct 17, 2021 at 04:32 PM.

Oct 17, 2021 | 04:35 PM

Ghost2017

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Oh crap... the battery is busted around the positive terminal on the driver side battery... still showing 12.7 volts though. I don't think that would cause this kind of randomness though...

Oct 17, 2021 | 05:05 PM

smikesF350

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Could be an electrical ground issue. Corrosion at a point of ground or in a common plug connector.

Oct 17, 2021 | 05:42 PM

cficare

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From: SEVA

Quote:

Originally Posted by Ghost2017

Oh crap... the battery is busted around the positive terminal on the driver side battery... still showing 12.7 volts though. I don't think that would cause this kind of randomness though...

Don't rule it out. I've had to replace batteries in two separate Ford Explorers my wife has owned, and both of them displayed some very strange electrical symptoms which went away completely after a new battery was installed.

Oct 17, 2021 | 06:00 PM

Ghost2017

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Quote:

Originally Posted by cficare

replaced both batteries, no change. It's still popping the abs light and turning on my driver headlight. I think a bcm or something is going haywire. I'm just going to take it in tomorrow. I had my APIM replaced a month ago because my navigation and microphone went out.. well my nav is fixed,, but people still can't hear me when using the Bluetooth. So hopefully they can just get it all sorted out in one shot... also, today my truck said "no key detected" and then honked and locked my doors when I closed them. So that leads me to believe a module is bad.

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Oct 17, 2021 | 06:14 PM

4wheelsandahitch

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What a mess. Keep us posted.

Oct 17, 2021 | 07:31 PM

#10

morehouse7

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Did you check the infamous connector by the spare tire for corrosion? You have a bad wire or connection tied into your brakes and that's why it happens when you press them I believe.

Oct 17, 2021 | 07:34 PM

#11

Ghost2017

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Quote:

Originally Posted by morehouse7

Did you check the infamous connector by the spare tire for corrosion? You have a bad wire or connection tied into your brakes and that's why it happens when you press them I believe.

elaborate...??

Oct 17, 2021 | 07:39 PM

#12

BSHORT

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Every time I've had an odd electrical issues, it has always been a bad ground. Always. Just have to fine the one...

Oct 17, 2021 | 07:43 PM

#13

morehouse7

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Quote:

Originally Posted by Ghost2017

elaborate...??

There's a connector in the rear of the truck near the spare tire. This plug has been a problem for lots of people when it gets water intrusion and corrosion. Pop it apart, inspect and clean it out and add dielectric grease to it. I'll go out and snap a picture of it.