http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=54207http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=43&t=56907&p=633698&hilit=Install+updated+diesel+fuel+filter+head#p633698http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=52932&p=591671&hilit=Install+updated+diesel+fuel+filter+head#p591671The plug closest to the center of the vehicle uses the same wires and plug you already have. It's only a temperature sensor.
The plug closest to the left edge of the vehicle (as you sit in it) is the heater plug (300w) and it is the one you need to change.
Easy, just assemble the plug so that it plugs into the new head, and you get continuity through the heater circuit.
Slip the shrink tubes over those new plug wires.
Take the old defective heater plug from the old heater unit, and cut the plug off, then strip the ends of those wires.
Join those 2 wires to the 2 new plug wires (doesn't really matter which side goes where) Butt clamp, solder, whatever method works for you.
Pull the shrink tubing down around the wire connections, and heat them up to seal them.