New guy here, So I'll jump right in.
I sold my 97 zj after fixing all the known problems they seem to be known for and now have the '03 with it's issues. Loved and love both these Jeeps and bought the '03 knowing these two things may need attention.
Checking around I find there my be several reasons and or fixes for these bugs and not wanting to be waste time or money I thought I would ask for your opinions on what to check out first. I guess I'm looking for the #1 reason.
#1 HARD STARTS. No rhyme on when, sometimes when hot, sometimes when cold. What to check or change first? Plugs, sensors, filters, pressure? Vehicle was serviced regularly so don't know why this problem persists.
#2 HEATED SEATS. I know there was a recall but there are none outstanding for this vehicle. Passenger seat works and switch light glows. Driver side doesn't and switch light does not come on. Have seen these solutions: Switch module defective, wires pinched under or on side of seat, replace all heating elements.
So where do I start?

 

1) Most likely the o-ring in the fuel pump? fuel filter? is bad... fairly common problem. Mine cranks for 2-3 seconds before starting if it has sat for more than a few hours(and lost the pressure in the line.) You're right it could be a number of other things (low battery?) but I think this is the most likely cause.

2) Most likely an element needs replacing. I think there are folks who will 'fix' the element by soldering the breaks in order to extend its service life, but there are quick-fix-kits to replace the element and wiring for reasonable low cost.

Good luck.