My 2003 Jeep Grand Cherokee will not start. I

left side loose wires and connectors.
or shorts, in same wires will put the flasher in to overload fail mode
intermittent blinker switch, did you try to wiggle it to see if it is in fact flaky?

the valve body may be the issue in transmission

does is crank but no start,and are you getting spark to thw start plugd

Jeep Grand Cherokee is notorious for broken blend-air doors. This is the door inside the A/C-heater housing that switches the air from hot to cold. You must remove the dash to repair it.

IF BULBS IS OKAY I AM LOOK AT A FAULTY TURN SIGNAL SWITCH.

i know on the 99 mountaineers with the 5.0 the way the fuel lines were routed from the factory, heat from the motor would vaporize the fuel in the lines when engine was cut off warm. It would turn quite a few times before starting after that happened. try turning your key on and off a couple of times before you actually try starting it and it should start quicker. I know this from experience.

does it turn over?? check coils or coil packs.

go to autozone they will check codes for free

Since you added coolant, now it is time to check the fans. If the fans do come on, than your thermostat needs to be replaced, Should be done every 4 years anyways.

could be a grounding issue.