If you set the directional control for the air to flow thru the ac-vents only, you'll probably notice that the fan is set on low or high, and stuck there - regarding the front blower motor. The rear probably works normally. If this is the case, it's probably the heater blower motor RESISTOR that needs to be replaced. If not, then you may need a new front heater blower motor. Hopefully it's not the switch, they're expensive.... Good Luck. When the front blower motor is stuck on low or high, it's ususlly the blower motor resistor.
Your front blower motor has gone out. There is a front and a rear blower motor.
Possible blockage in the rear air units expansion valve. I just replaced mine for the same reason.
There are separate expansion valves in the rear, so even if the front system is failing, the rear unit could still work normally.
replace front heater corefront and rear have independent heater cores
There are two separate accumulators one for front and one for rear
probally closed or clogged
"http://wiki.answers.com/Q/Why_does_the_rear_ac_in_97_chevy_venture_blow_hot_air_when_the_front_ac_blows_cool_air"
Most likely the rear expansion tube or valve is defective.
There is a secondary condensor in the rear of the vehicle that works off of the primary. If the AC in the rear is working and not the front, it could possibly be the air handler or the blower up front. Does the front blow air? If so is it ambient, hot, or a little cool? Incorrect: The 1999 Tahoe DOES NOT have a secondary condensor the only thing it may have in the rear is a heater core IF it is supplied with rear heat, if you are getting cold air in back and not the front usually means you are low on freon.
i own a 2001 Chevy venture warner bro. edition. and the rear air blows hot while the air is on up front.. i had it checked out and the rear has no ac its just a fan for the back..go figure. my customized Chevy express full size van does the same thing
The back fan only works with the heating system. It only helps to blow around air when in cooling mode. In other words, it doesn't have a A/C coil like the front. Hope that helps
It appears that it is low on freon. Did you evacuate the system??? Take it to an a/c mechanic. could be the "head unit" or A/c contols in the dash.