hell another tech has 2004 ford expedition front and rear a/c.the front blows warm but rear blows cold,the low side gets cold till the line that runs to rear and the other part of line that runs to expansion valve gets very hot!tech has already replaced expansion valve and a coulple of hoses!he removed a/c clines at evap core and blew air through it seems like no restrictions and through the condensor.a/c pressures low on both sides and also looks like low side wants to go close to vacuum!hoses from compressor are new and drier.can hear a hissing noise under dash also,he thinks it freon rushing through evap core!

William from Maryland