[stallion112]

Here's one for all you electrical experts out there.

My Kellison Stallion, which was built in 1978, has a cigarette lighter in it. The lighter works fine. I checked the power to the back of the unit and it is 12V. The ground wire is in good condition and well grounded.

When I plug a cell phone charger into the socket with the phone turned off, the phone manufacturer's symbol lights up as it always does but instead of the battery icon with the percentage charge then being displayed, a question mark is displayed and then goes off.

I checked out the socket in one of my newer vehicles and visually it looks about the same internally. It too is reading 12V. Any suggestions?