I am having problems with my 97 F150 keeping it's charge. It's a 4.2L Engine V6..3 door crew cab...longbed...4x2...and has 88k miles. I have replaced the battery with a new one, took the alternator out and had it checked...it's fine, checked the ground on the starter & battery, checked the starter...it's fine, did the test light on the battery for every single fuse, changed the ignition starter switch, changed the starter solenoid. Nothing has helped. When I go to crank the truck nothing at all happens. no sound and no lights. It will run about 3 days on a full charge. Here is what is happening though....The battery is still pulling a charge from somewhere...the meter read up to 0.34,(on the battery) key off, doors shut. Windows will only roll up & down when key is on accessory. It kept blowing the 15amp fuse, traced & checked for shorted out wires and nothing. I found a semi disconnected GPS c-chip installed in my truck underneath my steering wheel column when I removed the panels. I'm assuming that the truck previously belonged to a rental car or leasing company. I traced the wires so that I could remove the c-chip completely. While tracing..I also found it connected through my factory radio wires down to some sort of audio/video device which helped support the c-chip, from there I traced the red wire to my passenger kick panel where it was connected in somehow with my FUEL RESET!...ARGGGG!!!! It was wired in to 2 12v Aftermarket Orion relay switches that had the wires connected to the prongs! I cut the red wire and then pulled them from the relays completely. Truck cranked just fine (on charger) Then I just said to heck with it and pulled all the wires out of the relays. Which were also connected to a separate c-chip fuse box. Anyhow, I'm just ready to shoot this truck. But after pulling all the c-chip crap out it now reads 0.96 on the voltage meter. Why are the amps going up??? But if I also pull out my #21 fuse under the hood and my 2 interior accessory fuses below the dash it goes down to 0.01. I'm at a loss and am tired of trying to figure this out. Any help would be grately appreciated! Sorry so detailed. But at least it gives you an idea of what I'm going through...LOL.

 

Welcome to the forum.
Electrical problems can be a PITA to figure out.
We'll start with the saftey issue first. Does the truck have cruise control? If so, try unplugging the pressure switch on the front of the master cylinder. If the amp draw drops, then the switch is probably bad and is trying to burn your truck to the ground if it is internally shorted due to brake fluid getting into the electrical part of the switch.
If that's not it, there could be something in the GEM module stuck on. This controls alot of electrical accessories in the truck. It could also be something like a power door lock switch stuck in one position or the other.

 

Yes it has cruise control but it does not work. It didn't work when I bought the truck. Also the horn never worked and the Airbag light will flash on and off constantly. I thought that the recall for the cruise control switches were for the 2000 Fords. It's better to be safe than sorry though. Thank you for the info. I appreciate it. I'll try everything that you suggested.

 

The recall covers pretty much all of the late '90s and early 2000's trucks. My '97 was recalled. Make sure you disconnect the switch until you can get the truck in to the dealer.

 

could be your accesory delay relay. if it's not turning off, something could be staying on. check for lights staying on (hood light staying on?). also one or more of the modules may not be going to sleep....

 

Sounds kind of like my issue on my truck. I bought it last Summer and drove it for 3 days and the alternater went on it. So I went and bought a reman alt. from Autozone in Oct. 06 and just last week that exact alt. went out. They gave me a brand new one in the original sealed box and I hope this one last longer then a few months.