I have a 1999 f250 super duty and something keeps draining my battery, I replaced the old one and im having the same problem. What could it be?

 

Does the alternator feel hot after it has sat overnight?

If yes.....it's the alternator.

 

I'll look into it, I have been disconnecting the negative terminal on my battery but it doesn't always work. And sometimes it will start up with no problems after sitting for a couple of weeks.

 

Do you monitor voltage or anything with a Bluetooth dongle, Scangauge or Tuner? Have you load tested the battery or Alternator? Which Engine do you have? (Please update signature to reflect important details)

I had dirty terminals on mine, once cleaned voltage was back up to 13.8-14v.

 

unfortunately I don't have anything to test the volts battery is brand new, terminals are brand new. I have the 5.4 triton v8

 

Mine would drain randomly, sometimes it could sit for a week and be fine, other times the battery would be drained over night. Couldn't figure it out until one day I was driving and the speedo started acting funny, turn signals acted weird, then the speedo quit altogether. When I parked and took out the key I noticed the blower was still running... I started turning the fan to the off position every time I left the truck and it never drained again. Soon after I pulled out the GEM to make sure it wasn't swimming, cleaned it and all the electrical gremlins went away.

 

Buy a multimeter; they're handy and easy to use.

You can use it to test the battery while the engine is running; if the volts are over 14.8, then your alternator is overcharging and killing off your battery.

 

What did you do to clean the GEM?

 

I removed it, expecting to find evidence that it had gotten wet (which it clearly hadn't) opened it and cleaned all the brick dust out of it and the connectors. Apparently that was all mine needed to work properly again.

 

I'll tried to remove mine yesterday but it seemed impossible to remove...

 

I'll tried to remove mine yesterday but it seemed impossible to remove...

 

It can be a little tight getting to the bolts holding the connectors on, but it's not too bad.

Some guidance here:
https://www.ford-trucks.com/forums/1...k-and-gem.html

 

Thank you, I'll look at this tomorrow.

 

Found some corrosion. Is there a way to clean this? GEM wasnt wet or really dusty, but this part itself was kinda dusty

 

Compressed air should blow out any dust. If it doesn't, you can try a quality contact cleaner such as CRC
03070 -- Contact Cleaner, 14 Wt Oz