I have a WARN A2500 winch mounted to a 2001 Rubicon. This winch is about 1.5 yrs. old and has been used exclusively to raise and lower my plow (maybe 4 times the past couple of years). Recently, I began having a problem with the winch. The winch takes up spool fine, but when releasing spool (i.e. lowering the blade), the cable sparks at the roller fairlead, and the engine shuts off. Nothing abnormal happens when raising the blade, only when lowering the blade. The engine starts back up fine, but will immediatly shut off if I attempt to release spool. The spool release seems slower than it should be. I tested the current at the contactor ... 12 V from the battery, when I engage the winch with the switch, the solenoid sends about 9-10 V when taking up spool, and only 3-4 V when releasing spool. All electrical contacts are clean and tight. Comments? Bad contactor?

 

Sounds like a bad connection somewhere. Could be shorting 12v from the cable to the frame causing the bike to stall. 1st time I've ever heard of this though.

 

Check all the ground(-) connectors.

 

Definatly sounds like a short to me, I would start with the grounds first aswell.