Hey guys,

I'm working on a friend's 93 V6 3.0 EFI. The battery drains constantly even after engine shut off, and when I jump it, the windshield wipers go on permanently. Eventually, with the truck off again, the battery will drain until empty.

Thoughts?

Thanks!

Charge the battery, pull all the fuses and relays (and remember where they go) and check the fuse terminals to see if something is grounding out.
Check the function of the relays with a 12 volt power source on the bench to see if one is fried. Put the fuses back one at a time and see if you have any battery drain by taking off your positive battery terminal and checking voltage across the terminal and post to see if adding back the fuse caused any change or indicated a switch that's fried.
Do you have any suspect components that don't work or always work, like you might have a wiper switch that's always on? Since you mentioned that one, I'd start by pulling the wiper fuse and checking to see if there is always current running there.

Get a Battery tester and run a full alternator test.

Get a fuselight and check every connection and fuse.

Disconnect the battery and try a new one. See what happens with that.

I can't recommend too many things at this point.