Gentlemen,Gentlemen,



I have a parasitic drain on my 85 F350 diesel, It is outside the fuse box. At some point in the trucks life it has had: snow plow, camper and trailer wiring installed. I have removed it all since it was all rotten anyway. It is back to 99% stock wiring. I pulled all the fuses and it still drains over night. If I unbolt the + power to the glowplug relay which of course feeds the starter relay the drain stops. These are normally hot as per the wiring diagram so not sure where to go now. Any ideas?

 

You have two relays to check. Maybe one of them has a short to ground?

 

disconnect the alternator and see if the draw goes away. also could be the voltage regulator.

 

You can connect a 12v tester or tail lamp-size bulb in series with the + battery cable. A drain should cause the lamp to glow. Then disconnect one thing at a time until the lamp goes out and you've found the problem. Completely disconnect one of the batteries. Disconnect positive terminal of remaining battery and insert lamp between battery and cable.

 

I have replaced the starter/glowplug relay recently. I pulled all the fuses and disconected the rear wire harness by the back bumper that shots off the trailer/lic. plate/blinker/rear brake/ rear park lights. No deal still has a drain.

Have not yet changed out the alternator to the 3g but plan on that when I get this figured out. How do I check the voltage regulator?

 

unplug it.

 

ok, that clear and easy. I'm guessing it should not draw power? How do I know to replace it?

 

If you are looking for a power drain and with regulator unpluged that drain would go away then regulator would be bad. If just measuring to see what it regulates the voltage to, use a voltmeter and look for around 14.7 dc.

 

That was it, you win the guessing trivia game!

Thanks!