I was looking at the grille of my ranger and i found an AC plug like what you use in a house. Its three prong and i am not exactly sure what it is for. Is it a engine block heater like diesels have? My truck is a 1999 3.0L v6.

 

Block heater or battery warmer.
May even be a battery maintainer.Sort of a trickle charger.

 

Maybe the previous owner installed a power inverter? If you are the original owner I have no idea. Do you have a volt meter? I would start the truck then see if you have voltage on the outlet. No voltmeter? Perhaps a small lamp will work.

 

my vote is a block heater

 

male or female?

 

Wirelessly posted (Android)

My 99 3.0 came with a block heater. That's my vote.

 

its a block heater, you may also have a wire going off of it that goes to a battery warmer pad thing as well.

 

Well I'll be darned. I thought block heaters were only found on diesels. Must be a northern thing.

 

It's a part of the "Cold Weather Package," an option allegedly only available in "cold weather states." The package consists of an electric battery warmer pad which wraps around the sides of the battery, and a block heater, which is inserted through a freeze plug into the engine block. Both are connected to the three-prong plug that pokes out through the grille.

If you park the truck outdoors, and you live in a "cold weather state" (Montana, Wyoming, N&S Dakota, Minnesota, Wisconsin, Michigan, or New York and perhaps a few others) the truck will start easier and deliver heat a lot sooner if you plug the cord into a 120 volt outlet overnight.