I didn't know some xj's had heater

 

FSM says it is in the first or second freeze plug hole (sometimes called a Welch plug) which is on the drivers side under the exhaust manifold. The location varied from year to year, but always in one of those two holes.

 

I took some pictures to try to help you out. Here they are in order from where the plug is to where it's plugged into the block. I have a block heater.

The wires for the plug (No plug attached)


Going over the pitman arm:


Pitman arm to block:



Hope these help, considering I laid down in -10deg snow to take them

Edit: Driver's side.

Edit: Yeah, my power steering is leaking and I can't find the leak

 

awesome pics thanks for them i've been away from the jeep for a couple of weeks so i haven't kept looking for my heater i'm sure these will help i'll post back if i find it or not.

 

I am thinking you do not have a block heater if it is proving that hard to find. I am about to order one for the 4.0 for about 30 bucks + shipping.