Batery goes dead overnight

[Copytech]

I have a problem on my Ranger that i can't figure out. I bought this truck as a weekend play toy but if I don't disconnect the battery it will be dead the next day.

Anyway the yellow wire going from the starter relay to the fuel pump relay (and ecu) is pulling a constant 1.2mA. If I disconnect this wire the battery will stay charged. I am going to assume that the ecu is always on but why. I can't figure out what pin should be switching the ecu on and off.

Thx
Kevin

 

[Roadkill]

You need to find the ECU relay in the main fuse/relay box. Pull it with an Amp meter on the battery positive and see if Amperage drawn drops to less than .1A. If it does then you most likely need a new ECU relay. I had one go bad on my Contour and that was the culprit.

 

[Copytech]

I tried taking the relay out, no luck it still pulls current on the same wire. The truck won't run with the relay out. I'm stumped.

 

[shadetree]

I would take the large wire off the back of the alternator just to clear that part of the electrical system. If the drain remains, the yellow wire also goes to the fuel pump relay. Pull it and check for a change. If no change, do a resistance check on the wiring.shady

 

[88broncoll]

im with shady, ive seen a few of mine do this over the yrs. drove one all summer, opening the hood and connecting the alternator wires every time i started it. the regulator in the alternator blows some .05c diode and continually draws amps. You can get a new regulator put in it for about $50 around here anyways, but a reman is in your future