I drove my 93 F350 the other day and when I was going to leave it wouldn't start --no power at all (no lights, nothing on dash). It jumpstarted with a battery pack. It was dark and I noticed the amp gauge was pegged to the high side once it started and then when I turned the lights on it it drew it down and almost wanted to kill the engine. Made it home but every time I presses the brakes or used a turn signal amp gauge would drop. I put a spare battery in it the next morning and it started right up drove 40 miles to store, shut it off, it restarted and drove over to the gas station where it again had no power at all. Jumped it there and made it home. With it idling in the driveway I had near 14 volts on battery and fender solenoid so I shut it off and disconnected the ground cable. 3 days later I went to move it and hooked the battery and again no power, battery had 12.4 volts. I hooked up cables from another vehicle and let it run for at least 15 minutes but this time I couldnt get more than 12.5 on the truck battery but I had almost 14 over on the solenoid on the fender. The starter clicked but that was all I couldnt get it to turn over. Sorry for the long description but I wanted to give all the background. For kicks, I charged both batteries I had used with a trickle charger out of the truck and they both got up to 12.8 or so and then I took the charger off and let them site overnight and came back both were about 12.6 or 12.7. So I dont know if I am dealing with a alternator issue(reman one on it when I bought the truck), or a bad cable or what. But I would appreciate some guidance or advice. My next move I guess is to put one of the batteries back in now that they have charged and see what happens and if I have good voltage at starter. But It really baffles me why I cant even get lights--it seems even with a weak battery the dome light would work??? Again any advice is appreciated. Thanks

 

Never run the car your jumping from. Just use its battery. Jump the dead car. Immediately disconnect. And for most new cars they can't be jumped. And if you can get a load test and alternator test. The tester is about 40 bucks on Amazon for the battery. And you can get the alternator bench tested at a decent parts store. They have a machine that will dyno it and tell you if it works and how many Amps it makes. But none of that matters if the power cables are all worn out. From corrosion or age. Need good battery connections and grounds. And the ground strap to the firewall matters.