My Dad's 1989 F150 5.0 4x4 has a short that drains the battery overnight. Could someone please help me find the problem. The truck sits alot, has very few miles on it, and is in perfect condition. He passed away 3 weeks ago and I'm going to work on it for my Mother so she can drive it without letting her stranded. Thanks for your help. Russ.

 

A few simple things to check:

1. Glove box light (bad switch)
2. Interior lights (bad door switch)
3. Underhood light (bad mercury switch)
4. Check the battery connections, also make sure that the ground cable connection is clean where it's connected to the block or frame.

If none of the above solves the problem, take the battery to a auto parts store. Most of them have a machine that can test a battery. It could be that the battery has a bad cell.

Good luck.

 

Thanks for your help. I'll be looking at it again this week. Dad's death was sudden, he had thought maybe it was the battery so he bought a new one. The parts store told him when they connected the cables to it there was quite a spark. I'll check what you said. You sure have a sharp truck. Where did you get your aftermarket antenna? I recently bought a 2002 FX4 and my factory one hits everytime I pull into the garage. Thanks again, Russ.

 

I'm embarrassed to admit it's been a few years ago and don't remember where I bought it, but if you do a search for Trenz Billet you'll find a few sites that sell them.

I just thought of something else concerning your battery problem. A few years ago I had an '86 Ranger that kept running it's battery down, and finally traced it to a stuck fuel pump relay (fuel pump was running even when the engine was off and key out of the ignition).