2003 Grande Jeep Cherokee Loredo

Went inside to eat came out won't start but it turns over. Had it towed to mechanic, been trying to figure out why won't start for 5 day now. The gauges won't go up to were there suppose to be at either. @ mechanic shop there is no power to the injection fuses or to the TCM but both fuses are good, was told the wire harness in driver door can short out so we wiggled it and then the gauges would work sometimes and sometimes not. There's no fuel pressure, injection not pulsating, will not allow the code reader machine to read codes, it has been raining here about a week ( what does this have to do with above?) put a new crank shaft position sensor in it it started but then died won't start again. Mechanic went out turned the key on the gauges worked for a sec then nothing again when he tried the key again. Don't know were to begin drove it the night before and no issues never had this issue before either until Thursday of last week. I depend on the vehicle as it is my only one and I am disable needing it fixed thanks for any help in this! Oh yeah it's a 4.0 liter and a straight 6 also. Really appreciate the help thanks in advance