2005 International 9900ix ac problems

Looking for some ideas on the ac system on a 2005 International 9900ix with a ISX 15 L Cummins. Here’s a run down of new parts and what we’ve done so far.
a/c condenser
ALL a/c hoses are new
Receiver dryer
High pressure sensor up by the compressor
Expansion valve is new
Evaporator core is new.

After all of this was installed we completely vacuumed the system down. Went to start filling the system with freon and the a/c compressor clutch won’t engage. No power to the compressor. The breaker in the glove box is good, as are the 2 relays in the glove box for the a/c system. The light comes on in the dash when the a/c button is pushed. The only things that haven’t been replaced are the pressure sensors on the expansion valve, and the compressor itself. What am I missing with no power to the compressor? Any and all help would be appreciated, thanks in advance!

 

I believe this one must not have an apads system. I checked both sides of the firewall and did not find a module. On the left (drivers side) was the normal wiring harness going into the firewall along with some air lines. On the passenger side (right side) was more of the same, more wire harness’s going into the firewall. I will try and get some pictures monday to post just to make sure I’m not missing something. In the meantime, I did some checking with the test light. I pulled the relays again and found the relay on the bottom of the fuse panel labeled for the ac did not have any juice on any of the terminals. The relay on the left side of the fuse panel had power on 1 of the terminals. Not having a wire diagram to go by, I figured I would pull out the control panel and test on the backside of that. I probed every wire to do process of elimniation, and found power in, but Could not find a wire that gained or lost power when the ac switch was turned on and off. So knowing this, is it common for that control board to go bad? I assume power into the board, then power would go back out to one of the relays?? Or should I still be checking the freeze switch under the seat first? Thanks again for your help!!

 

Thank you very much for the link. Turns out the main control board (where the A/C button is to turn on the system) was faulty. There was power going into the board, but when a guy pressed the A/C button it wouldn't send power back out. Figuring out which wire ran from there to the relay was probabaly the trickiest part, but after enough probing with the multi-meter I was able to figure it out. Now after that, thanks for the jumping the freeze switch wires, because after I restored power to the relay, still nothing to the compressor until I jumped those wires, after i jumped them, boom, power to the compressor. Again, thank you, your knowledge and guidance has been great!! Now off to find a freeze switcch.