So,I just bought a 94 F150 XLT. It's a 5.9 EFI. It seemed like it was in fair shape for a farm truck but some very strange issues have popped up. I was driving at night and turned on the brights and the headlights and dash lights went out completely! I turned off the brights and thankfully the other lights came back on. Next,I let it sit for a few days and when I went to start it..nothing. No click,no nothing. I took the good battery out of my car,put it in the truck..nothing. When I put the battery back in my car it was dead. Luckily I was able to quickly recharge the battery to get the car started. I have the Chiltons manual for this truck but electrical systems are my Achilles heel. Any ideas or suggestions? Thanks in advance. Dan

 

I can't imagine anything draining a battery that quickly. Well first step in system diagnosis is to start with a fully charged known good battery. So start there, have the battery load tested. Then check for a parasitic draw by connecting a multimeter between the negative cable and the battery and measure for amperage. Make sure all accessories are turned off first. If you suspect a high power drain or a short you may want to try this safety test first because meters can only handle up to 10 amps. Get a fuse @ 5 amps and hook it up as a jumper between the negative cable and the battery ( just like you would the meter ). If the fuse blows you have a short somewhere and you don't want to hook up the battery Untill you can find it. It can cause more damage or fire.