When I try to crank it, it wont even turn over...nothing even clicks...sometimes all the dash lights die....the battery is fully charged....just replaced the starter, starter solenoid, EGR valve, Alternator...and reconnected a wire that was loose on the IAC valve....think its this wire I reconnected?

 

Many time's the cables are at fault or their ends. Also check at the motor ground for tightness, corrosion.

 

Ran the code reader and got these codes:

Code 21: ECT out of self-test range.

Code 24: ACT sensor out of self-test range.

How serious is this? And what parts do I need to replace to get this thing going again?

 

Those sensors will not keep the engine from cranking. Is it manual or stick? I would check the mlps if a auto and clutch safety if manual. If it will not turn over by jumping the solonoid then you have to have a broken wire.