67SS&99SS

iTrader: (7)

My uncle has a 1994 Z/28 and I've been driving it here recently and have noticed an issue with the A/C. When driving, I can have the A/C on max cool and the fan speed on 4 and all of a sudden, the air speed from the vents will just about go to nothing, and stay that way for 10-15 seconds. Then it will slowly speed back up to to the max speed. This is cyclical. Every 2 minutes or so this will happen.

I have replaced the blower motor and this did not correct the issue. Is there a vacuum actuated door, that allows air to flow, that could be closing and opening causing this issue.....or some type of resistor for the blower motor? It's starting to get close to the 90s here in Georgia and I want to get this fixed as soon as possible. Any help would be appreciated.

wssix99

iTrader: (5)

Yes. All the vents are controlled by vacuum actuated doors. I'd check the vacuum lines in the engine bay first that feed the system.

I assume the pitch of the blower motor, doesn't change, right? If that's the case, you should notice the air coming still coming out - just through the wrong vent.

Homeless2bNY

iTrader: (2)

if you are saying the blower motor speed goes up and down, there was no reason to replace the motor. it was working.

pull out the blower motor resistor and inspect it.

the resistor controls blower motor speed.

there is no reason to look into you blend doors
cause you dont have a problem with mode selection.

blower motor resistor