98 Suburban AC only cools when rear fan switch on

Chevy Forum Chevy Classifieds Photo Gallery Chevrolet News Search Contact CF Sponsors
Member List Forum FAQ Chevy Timeslips Chevy Recalls TSBs Calendars Register Login

98 Suburban AC only cools when rear fan switch on

Printable Version

Chevrolet >> Chevy Trucks, Vans & SUV's >> Suburban >> 98 Suburban AC only cools when rear fan switch on

Page: [1]

Message

<< Older Topic Newer Topic >>

98 Suburban AC only cools when rear fan switch on - 6/14/2007 12:45:19 PM

txmaui

Posts: 1
Joined: 6/14/2007
Status: offline

98 Suburban AC only cools when rear fan switch on

I have a 98 suburban and recently noticed it only blows really cold air in front when the rear temp control fan is turned on.

Front AC switch on, front fan switch on (speed doesn't matter), rear fan switch off. Used a temp gauge in the center vent and the air does blow colder than outside ambient temp but not much ~ 70 -75 degrees. The compressor is on. As soon as the rear fan switch is turned on (low), the air in the front vents starts to drop until it reaches around 48 degrees where it stabilizes. The rear also blows cold.

For the above scenarios, the front re-circulate switch and front fan speeds do not change the behavior. (e.g. the front only blows cold when the rear fan switch is on).

Measure the low and hi pressure cooling system sides last night and results below. The AC compressor was replaced several years ago and have not had any issues since then until we noticed this.

Any idea what may be causing this?

switch positions Low Press Reading High Press Reading Notesfront on/rear off 25 175 compressor on 45 125 compressor kicks off when rev'd for a while when low press drops to about 20 front on/rear on 30 200 idle 45 240 rev'd - compressor does NOT kick off front on warm/rear on 45 225