Battery light comes on when key is off....

First time for everything....I just got home with my wife and needed to park my truck (1986 Ram 50)...started right up nothing unusual, backed up and pulled into my regular parking spot...turned the key off and the battery dash light came on.....started the truck back up....the light goes off....did this 3 or 4 times...light goes out when truck starts...light comes on when the key is turned off...disconnected the neg. battery terminal and the light went out....electrics are my absolute worse nightmare as I don't know squat about it...anyone have any ideas before I take it to a shop?

make sure all grounds are in great shape & use di-electric grease wherever possible...you know check battery ground to cab, frame, engine etc...(i add grounds)...i added a ground cable for <$1.00 @ rockauto promo code 2286565420978579 This discount code expires on August 10, 2014; so don't wait!

Just went through the EXACT same thing with my truck. Replaced the alternator and the issue went away.

Thanks ragragtimetime....your suggestions are on my list but I found out the alternator is toast...apparently a diode died...took it in to O'Reillys to test and it failed.

Thanks Haruman....it is the alternator...had it tested...I jumped online and found a site with an auto electric tech with 40 yrs experience posted on another post with the exact same problem...it seems a diode (if I remember correctly) has gone south and causes battery current to flow back through the sustem when the key is off...hence we get the bright red light...thanks for the response.

Replaced the alternator and he's back on the road....seems happier, runs smoother and has more pep...I guess a few more milivolts can't hurt.

And the MightyRam50.net forum comes through again. No one can say we haven't got the best Mitsubishi, Ram50, D50, Arrow people on the planet. :thumbup: