so I'm looking at a 1989 7.3idi and it's nice but has a wireing/battery issue. the battery drains fast sometimes within an hour. I've figured since it's a fast drain, it's not a bulb or something like that. anyone have an idea of what it could be? glo plugly relay?

 

It's something simple, that's for sure. There isn't too much inside these trucks. Just get yourself a multi-meter from Harbor Freight(or elsewhere) so you can measure current draw one wire at a time, and trace down that drain!

 

within an hours' pretty bad .. like a dead short somewhere ..

or .. maybe just a cell is dead in the battery ..

each of 6 cells carries 2 volts so if one is dead it will go to 10 fast ..


they did try another battery first and it's still doing it right right ?

 

he says the battery is good. so the only thing I could think of is the glo plug relay? that seems like the only thing to draw a decent amount of power

 

Disconnect the relay and see if batteries continue to drain.

Is only one battery draining? If so, that's more likely the battery itself. What happens when both batteries are disconnected?