On my 03 accord no power to a/c clutch

Clutch coil bad . The A/C compressor clutch coil is a electromagnet an you need to check it with an ohm meter . Check out video on youtube testing A/C clutch coil .

If it is a fluid system then check if the fluid has"nt leaked out, then try to bleed the system if that fails then the clutch is stuck on the flywheel or pressure plate. Try towing the vehicle and gently release the clutch pedal so that the vehicle moves on its own accord. Do not release the clutch to hard you may bust the gearbox

About the only thing you didn't mention was the starter itself. You could have it tested. But before that, try to see if you have power on the small wire to starter solenoid on the starter, when key is held in cranking position. Pull the small wire off and check for power with a multimeter or a testlight while someone holds the key in crank. This is the signal wire from ignition switch that closes the elec. contacts inside solenoid so the starter gets full power from the battery to spin. (This wire also is in the circuit with the clutch switch and the starter relay.) If you have power on this wire in crank, it is very likely the starter is bad. If there is no power, check that circuit out. It is losing power somewhere from switch to starter solenoid. Good luck.

It seems you have a throw out bearing at fault, got to dis connect the transmission for that one

First item to check is if the refrigerant has enough pressure. Low levels of fluid will damage the compressor, so the system protects itself by not allowing the compressor to operate. (It cuts out the voltage to the relay/ clutch. If the pressure checks out ok, then check the relay and associated wiring.
As a last option check if the clutch is working. Do this WITH THE VEHICLE TURNED OFF, by applying 12 volts directly from the battery to the clutch terminal. You should hear a loud click if the clutch is working alright.

This indicates that there is a fault in the wiring. Check for A/C fuse.

If the clutch isn't cumming on you want get A,C faulty ac motor.Change

check shift fork adjustment. make sure you bleed the slave cylinder.also check shift cable adjustment.

Is the plate, the pressure plate. It lost the tension.

I hope to god he replaced the clutch. The older srt4's have a horrible design flaw where instead of having the flexplate heat up and warp and stop working alltogether, it grenades and takes out the transmission and sometimes the intake manifold. There are horror stories all over the internet.

http://www.srtforums.com/forums/f213/exploding-clutches-184381/

As for putting in a different computer it should all work fine if it's the same year. I've heard of people switching ecus to see if the ecu was the problem. It sounds like he has a decent amout of money into the car so instead of going with the factory ecu have him buy an aem ems. It's a stand alone performance based aftermarket computer. If you want to have full control over your engine a stand alone ecu is the way to go.

There are also cheaper ones but aem is one of the best and pefered by most tuners.

If he has any problems have him join that forum, fixya is more for generic questions. I'm sure that forum will have more than enough information for your son.