Hello,
I have been having a parasitic draw on my battery for a couple of weeks now, it just showed up from one day to the next. I coped with it by taking off the negative terminal every time I stopped, which started to get tedious fast, so I wanted to track down that draw. I did my research and started with the fuse test (pulling one at a time). I pulled all my fuses and my 3 amp draw was still there. Next, I disconnected the alternator wire from the relay. The parasitic draw was gone. When reconnecting it would make a clicking sound. That led me to believe that the alternator was bad. Now after pulling a night shift and putting in my alternator in the light of a work lamp at 10 pm in my driveway I thought I should check if the draw went away. Guess what. It is still there. So after some cussing and contemplating my choice of hobby, I sat down and turned to yall for help. Does anyone have an Idea what a potential source of draw could be?

Thank You

 

When you shut down, do you get a fast clicking for a few seconds, then a slower click?

My purge solenoid was still clicking away after the few second shutdown period. The relay for it failed, and it would drain the battery in a day or two.

This was in an E150 and I would never have found it but for the mechanics at work who had dealt with hundreds if not thousands of E250s and run into the problem before.

It was under the kick panel on the passenger side, up above the opening. Easy to get to if you knew it was there.

 

Are you talking about the heavy output wire from the alternator, where it connects to the starter relay on the fender, aft of the battery? And the clicking sound, did it come from that same starter relay or some other relay?

I'm thoroughly confused, as the starter relay doesn't do anything until the key is turned to start. One of the big terminals (upstream side) is used as a convenient junction post, but the relay itself shouldn't do anything when the battery is first connected.

Model, engine, and year are needed, too.

 

It is a 1981 F250 with a 351m in it. Yeah, I am talking about the fender mounted relay. In my wiring, the positive battery cable is connected to the front facing side of the relay, the positive cable from the alternator is connected to the same connection. (So positive battery cable and positive alternator wire are sandwiched on one bolt.) when I undo the nut on there, disconnect the positive alternator wire, but screw the positive battery wire back on, the draw goes away. When I touch that wire back to the connection, I heard a clicking sound coming from the alternator itself.

I hope this clears the situation up a little bit. I am not the best at describing these problems...yet.

Thank You

 

Pull the plug on the regulator. If that makes the drain go away, check to see if you have power on the green/red wire going to the regulator. It will be on the S terminal or the I terminal depending on how it's wired.

 

Hmm, that's a weird one. I can't think of anything in the alternator that could make such a noise. Does the new alternator make the same noise?

Here are the 1981 wiring diagrams. See pages 12-17:

1981 EVTM - Gary's Garagemahal (the Bullnose bible)


I vaguely remember mention that the 1980 wiring was quite different. Maybe somebody could chime in to be sure.

One thing I did notice was the radio noise suppressor at the voltage regulator. Could that be partially shorted to ground? Disconnect it to see. Unbolting it from the fender would be sufficient.

Is your alternator output normal?

And definitely check the regulator as Dave has suggested.

 

I just went out and unbolted the voltage regulator. The draw was still there but fluctuating a lot as I moved the plug, the regulator was also becoming quite warm to the touch. When I undid the plug the draw was gone, would that mean the regulator is bad?

 

 

Well, this was probably the fastest fix I have ever done. I went to AutoZone, got a new fancy regulator, and it plugged right in. The draw is now at 0.01 amps and the battery is charging. at 14.5 volts. I really appreciate the help, it would have probably taken me a while to isolate that problem on my own.

I also appreciate your reference. Gave me a good laugh. (Even Germans find that movie hilarious)

Thank you guys

 

I had the same issue where my parasitic draw would drain both of my group 31 batteries overnight (950cca each) and it was just the dumb voltage regulator. It even had a sticker saying "short proof" lol