1999 Chevy Express Air conditioning vents

NET9017

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1999 CHEVROLET EXPRESS

Air Conditioning problem
1999 Chevy Express V8 Front Wheel Drive Automatic 96000. Miles

I have a chevy express1500 conversion van that also has a vangater II wheel chair lift on it. This spring the front vents stopped working when I have the air or heat on in the van. I still get air and heat to the floor and the windshield but no other vents in the van. Any ideas as to what would cause this?

1 Reply

DAVE H

MECHANIC
13,384 POSTS

Hello. Thanks for the doantion. Much appreciated

On all models except "C" and "K" series, vacuum actuators control mode valves to regulate flow of air through heater unit. On "C" and "K" series, mode valves are controlled by a cable mechanism.. Check the vacuum lines to the mode doors. If vacuum lines are good the heat door may be jammed or broken

MODE SELECTOR
VENT Mode
Air is directed to instrument panel outlets.
BI-LEV Mode
Air is directed to instrument panel and floor outlets. A slight amount of air is directed to defrost and side window defogger outlets.
HEAT Mode
Air is diverted to floor outlets, to heat passenger compartment. A slight amount of air is directed to windshield and side window defogger outlets.
BLEND Mode
Air is divided between instrument panel and floor outlets, with a slight amount of air going to defrost outlets.
DEF Mode
Air is directed to windshield defrost outlets. A slight amount of air is diverted to floor outlets and side window defogger outlets.