A/C system 2001 Ford expy

Need to troubleshoot a 2001 ford expedition rear A/C expansion valve

there are 4 tubes connected only one is cold. The other 3 are warm (with engine and A/C running). Is this normal operation.


Connected a gauge (the cheap kind on a refill can).
Pressure fluctuates from 30~60 with engine running as compressor kicks on and off.
The compressor engages on and off rather quickly, like every 3 to 5 sec. No cold air up front. Weak air in rear.

ive included a pic of said part.

much thanks for any advice