on max a/c air blows out floor vent hard, weak from dash vents; floor vent blows on all settings except defrost..

Asked by us56730801 Sep 25, 2015 at 06:05 PM about the 1991 Chevrolet C/K 2500

Question type: Maintenance & Repair

the diaphragm at the floor vent works as it closes it on defrost mode; what
component would not be closing it on other modes like max a/c?

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Kelly answered 9 years ago

check for a broken vacuum hose..

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Andrew answered 9 years ago

They use a blend door motor, its most likely weak. Make sure the linkage isn't broken. It's under the driver side dash towards the center.

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