Can someone tell me the location of the glow plug relay for my 03 7.3l and is it hard to replace.

Thanks

 

It's not hard to replace 2 bolts hold it down, & 4 wires to swap over to the new GPR. The GPR it self is located behind the fuel bowl on the passenger side. it's brown you should have two that look similar, the 1st is the AIH relay, and the 2nd one is the GPR it's father away from the bowl.

It's that time of year I'm chasing down a GPR / glow plug issue my self.

 

Just to add to that.
Check this out. Pictures, Descriptions and the "HOW TO".
http://www.guzzle7pt3.com/s_gpr.php

 

Patn, it is possible that your '03 has a glow plug controller and not a gpr. It would be an aluminum finned box with two rectangular plugs on it it if has it, located on the passenger side of the engine in the valley area.

Hope that helps.