77NinetyEightmatt

Hey guys I have a problem with my ac coming out of my dash vents in my 98. I experienced it last summer after I got it recharged. It wants to blow out of the floor vents and takes up to 10 to 15 minutes for it to come out of dash vents. I don't know if I have a stuck door or bad vacuum line in there. But this summer I want to get that fixed so I have cold air right when I turn it on. What do you guys think and is this something a shade tree mechanic like myself can tackle?

joe_padavano

You are correct, the direction of airflow is controlled by vacuum-actuated flapper doors in the under-dash HVAC box. The problem could be one of many possibilities:

Sticking doors or actuators due to deteriorating rubber seals
Low vacuum
Leaking vacuum lines or selector switch in the HVAC control head on the dash
Sticking check valve where the vac lines connect to the vac storage ball on the firewall.

77NinetyEightmatt

So I would want to check the HVAC box first. Is that a pain to get into? A leaky vacuum line would be the easiest. If it has low vacuum then its a problem with the storage ball or a line right? And what if rubber seals are bad around flapper doors? Thanks a lot Joe

joe_padavano

Vac line is easiest. I think all the vacuum canisters are accessible from under the dash. A hand vacuum pump makes it easy to test each one. The rubber seals are inside the HVAC box, so disassembly is required to get to them. Replacement seals are non-existent but usually the rubber just gets sticky. WIping silicone grease on the rubber solves that problem.