Originally Posted by 86Scotty
So you're saying this is the other end of the 120v block heater wiring, as in the end that would plug to the unit/engine?
yes, the end shown plugs into the backside of the heating element. I'm not sure where Ford put the heater on the OP's 5.4. My guess is Ford incorporated the cord into the harness, 1 harness for all the vans of that type that year. At the very least, I'd hunt around for a heater element and the other end of the cord in the grill. I like block heaters in both gas and oil burners.
My '95 w/7.3 van was pre-wired with the cord incorporated into it's harness, and came with a factory block heater. Some previous knucklehead cut my cord flush w/the harness at the frame rail, left the block heater in to plug the hole. I tracked down a new Ford cord and installed it, I bench tested it, it works great. Came in handy in Flagstaff last January.