GEN 1 A new dead battery be issue

[jreaper]

A few weeks ago I notice an electrical humming/buzzing noise coming from my transmission pan area after shutting the truck off and removing the key. If left alone it slowly drains and kills the battery in roughly 6-8 hrs. The noise can be stopped by cycling the key all the way on(not cranking) then back off, most of the time, occasionally sticking on. I can also duplicate the noise by inserting the key without turning it then removing it, when the fuel pump primes, again most of the time(I'm assuming the pump priming when the key is only inserted is normal...?) Disconnecting and reconnecting the neg. battery terminal also stops the noise/battery drain.
I removed the transmission plug while the noise was happening with the key out and get 12v at the #12 pin on PCM side of the connecter(diagram shows #12pin as VBPWR-battery voltage) No voltage at the pin when the buzzing I stopped.

So battery voltage to the transmission is getting stuck on occasionally, killing the battery...is my understanding anyway.

Took it to the dealer and showed them since they had changed the leadframe a few months prior and the noise is definitely coming from transmission. After they changed my BCM, Key Switch sensor, and key cylinder($750 total over 2 weeks time and a "discount" on labor) the noise came back one day later.
It's hard to hear unless you are in an enclosed quite garage or you use a stethoscope on the transmission pan.
Sounds like a buzzing solenoid or relay. I can start and stop the noise at will some days, and other days it seems to be fixed.

Any help is appreciated
Sorry so long

 

[CoronaRaptor]

Damn, hope you called the dealer and asked wtf. Phone the service manager and tell him/her you cant just keep throwing money in the toilet for fun. Or, install a kill switch like the dragsters use on the outside.
https://www.jrracecar.com/manual-kill-switch/

 

[jreaper]

Haven't called the dealer yet. After they replaced the BCM, the next day before I picked it up they called and said the batt died overnight. Knowing I could stop the buzzing/drain myself by cycling the key, I picked the truck up for the weekend. I dropped it back off the next monday, that's when they changed the key sensor and said that didn't work either. I suggested the key cylinder was bad due to the door ding-ding not always working unless the key was wiggled, classic ford key cylinder. I told them to change that part either way and hope it took care of 2 issues at once. I got it back 2 days ago and could not get it to "stick on" playing with the key trying for 20 min. Today I get home and I can get it to stick on immediately and almost at will cycling the key a certain way.

One new note.
The truck battery HAS NOT died since I got it back.
After hearing the noise again today, I cycled the key to make it buzz and it shut itself of after, I believe, 5 minutes exactly, like it was something designed to run and then shut of. I tried this 3 times and every time it shut off itself. Before the dealer, it would run all night until the battery died.

This is getting weird.

 

[FordTechOne]

Sounds like gross dealership misdiagnosis. Amazing how they still charged you for an issue that they didn't resolve.

Where abouts are you in MI?

 

[jreaper]

Holy crap I think I found it! On a different forum and found this exact issue. Trans buzzing and all. Turned out to be a corroded wire behind the rear bumper/spare tire.

I'm near Muskegon. Think I can get my $ back if this is it? HAHAhahah!

 

[FordTechOne]

Holy crap I think I found it! On a different forum and found this exact issue. Trans buzzing and all. Turned out to be a corroded wire behind the rear bumper/spare tire.

I'm near Muskegon. Think I can get my $ back if this is it? HAHAhahah!

I would certainly try. The fact that you, as the consumer, resolved the issue so easily yet paid a dealership with professional technicians $750 to misdiagnose it speaks volumes.

 

[jreaper]

Well, I've had a Master mechanic license for 20 yrs. The only reason it went to the dealer was that I suspected the leadframe in the trans being faulty since they just replaced it under extended warranty

I did find a little corrosion on the wires(backup camera plug which I don't have and the tail light plug I think) mentioned on the other forum. Cleaned and greased.
I'll give it a few days at least before I'm confident in the fix

Thanks for the replies

 

[Riddick]

Just for ***** and grins you might want to check the fuel pump drive module back there. I know some people have had issues unrelated to yours, but worth inspecting. I’ve unplugged mine, cleaned and put a dab of dialectic grease in the plug for piece of mind.

 

[jreaper]

Thanks, I will definitely check it out. Speaking of the fuel pump, does it seem normal that the pump primes when the key is inserted and not turned? Before my '12 Raptor, my newest vehicle was a 03 FX4 flairside(383K and still kicking!) and anything that old primed the pump after turning the key.

 

[ezndo]

My 2010 does not do that