MY 97 f150 wont crank and when i turn the key completly over the door locks jump up and down.It did that to me 3 days ago and i got it pulled to the house then it cranked up. It did the same thing earlier today while in town and i kept hitting the lock and unlock button on keyless entry and it cranked up and i drove it to the house now here it sits. i know its not the battery and battery post. Anybody have any suggestions? They will be greatly appreciated.

 

This sounds is a problem with the GEM or the keyswitch or the leads coming from the keyswitch. or Anti Theft.

you said you have remote (fob) keyless entry or keypad
The GEM is an accessory computer module (General Electronics Module) that controls most non powertrain circuits.

Do you have a thick key head? or light on the Instrument cluster or light on the Light sensor


When did this start. Did someone try to hotwire the trunk? Never rule out rodents chewing through wires.

Pull the kneebolster down from th lower dash and take a peak up in there.