Just picked up my 2nd 1996 ranger. After fixing the engine, this one has a couple of strange issues: 1) with ignition off, gas gauge goes up to like 1/8 tank ( even if it's full)
With ignition on, it goes all the way down to empty. 2) wipers, once turned on, don't go off and don't change speed. 3) interior light, if it comes one, won't go off.

Btw, old owner swore that the gas gauge worked fine. This looks like a weird grounding issue to me but i do not have that much experience with eletrical on these trucks. Could it be the GEM?

Any ideas are appreciated.