I have a 1969 F-250 which has been my trusty steed for 5 years. Never in our relationship has she drained her battery. The other day, a friend asked me to move some stuff for her. We traveled about 100 miles that day in stop and go traffic. The truck ran fine.

The next day, I go to start the truck. Nothing. Fine, I say. That battery is obviously over 5 years old, no harm done. I check to make sure that nothing was left on, nope. I had some issue with the brake lights staying on, so I went ahead and popped in a new brake light switch. The alternator was still charging, as measured by producing about 13.5 volts at the battery when the truck was running, but I pulled off the belt, spun the pulley and it sounded a little rough, so I swapped out the alternator and belt. I charged everything up and of course the next day it was flat. So I swapped out the battery.

I expected this to be the end of the issue.

No.

My brand new battery was flat this AM. I was very disappointed.

The truck has no radio. The dome light doesn't work. The headlights were not left on. What am I missing?

 

Cigarette lighter stuck in the "in" position or if you have a glove box light, the door may not be shut all the way. The best way to find a current draw on these trucks is to remove the positive battery cable and put a volt gauge between the battery post and cable. If the gauge shows 12 volts, you are draining your battery. To check which circuit is the culprit, pull your fuses one at a time to see when the gauge reads zero. With a truck that old, most likely a wire rubbed through to ground. Or you can go to this site where a parasitic drain is better explained.........Battery Drain Parasitic Draw Testing
or here......http://www.2carpros.com/articles/car...dead-overnight

 

Thanks. I'll triple check those items. Whatever is doing it has to have a pretty good drain, it sucked a brand new battery down to zero in less than 24 hours.

As a preventative measure, I'm going to swap out the voltage regulator and starter solenoid tonight. The sticker on the alternator I bought said to swap out the voltage regulator, so I wanted to do that anyway and from what I have read on here the starter solenoid is a typical culprit as well. I had been kind of eying him anyway, so out he goes.

If that doesn't work, I'll pickup a voltmeter and go at it circuit by circuit.

 

I believe this problem has been resolved. Since I did several things, I can't say with absolute certainty it was the starter solenoid, but it would be my top guess. Now I need to resolve the other issue which is that whining noise (separate post).

Thanks!