I have replaced 3 batteries in my 04 f150 in the last 6 months. I have a draw some where in my system. My alternator is charing fine. If I let my truck sit over night, it is completely dead the next morning. I tried to locate the draw. I removed each and every relay and fuse one at a time with a test light on the neg cable and terminal, and no luck. I could not find the draw. Also my fuel economy on the highway is 10. And this weekend my heater went out. I tried changing the settings, turned the a/c on, and nothing works. Help me please.

 

What kind of electrical mods do you have on your truck?

Bigger Stereo
Amps
Lights
CB
Winch

It is possible that your alternator is the problem if the voltage regulator has gone bad and it can cause all sorts of things to happen including killing every battery that you put in it.

 

The only electrical mods that I have done to my truck are: car charger which is unplugged when I'm not using it, and a Sirius Radio, which is not hooked up anymore.

 

I would take a close look at all of your battery cables and ground straps on the truck. I would also have the alternator tested at a trusted shop. On the battery cables look really close at the ends of the cable and look for any type of corrosion that might be occuring if there is corrosion in the cable it should be replaced . As far as the heater is concerned I would start by tracing the wires that come out of the blower motor and check them for shorts with either a test light or Volt meter.

 

My truck is at the Ford dealer. I am letting them deal with it now. I am sick of fighting with my truck and worrying if it is going to run or not. I am about ready to blow it up and get rid of it. It seems like i get one thing fixed, then another thing breaks. It ticks me off that i am driving a new truck that i bought for 20 grand and the dumb thing wont work. I wish i never got rid of my dodge for this POS Ford.

 

I spoke with the wrenches at the dealer. They said that my truck is pulling 17.1 mpg. Heater was a blown relay. And the electrical draw is .2 and a normal draw is .5. I have a hard time believing that a .2 draw can drain my battery in a night.