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95 G20 strange problem
Posted: Fri Jun 20, 2025 11:30 am
by MichaelF
Hello all, new member here. I have a 1995 G20 conversion van I recently acquired with a strange problem. Sitting at idle, or coasting without any accelerator, everything is normal, working great. When I accelerate or cruising down the highway, it stops blowing out of the front vents, I think it’s still blowing, out of somewhere but don’t know, as soon as I let off the accelerator, the air returns to blowing out the front vents. New blower motor, AC itself working great. It’s just a cable accelerator that doesn’t seem to be interfering with anything. Any help would be much appreciated.
Re: 95 G20 strange problem
Posted: Sat Jun 21, 2025 7:06 am
by Cusser
Disclaimer 1. I am NOT an AC professional
Disclaimer 2. I have zero experience with a 1995 G20 conversion van
In general, air can come out the main vents at the driver, at the windshield (defrost position), or under the dash (heat position) or a partial combination of those.
But here's what I think (based on hands-on experience with a 1984 Jeep Cherokee): I suspect this van has vacuum-operated actuators which direct the air flow (that Jeep had three, and all went bad in the years we had it). So when engine vacuum changes as you drive, these actuators would change how they deflect the air.
Many more-modern vehicles have electric actuators which go bad too. Our 2014 Yukon has three of those, and in the 2 years we've had it, one actuator went bad. Same in our 2005 Yukon, and 1994 Suburban.
Re: 95 G20 strange problem
Posted: Sat Jun 21, 2025 11:28 am
by MichaelF
Cusser wrote: Sat Jun 21, 2025 7:06 am
Disclaimer 1. I am NOT an AC professional
Disclaimer 2. I have zero experience with a 1995 G20 conversion van
In general, air can come out the main vents at the driver, at the windshield (defrost position), or under the dash (heat position) or a partial combination of those.
But here's what I think (based on hands-on experience with a 1984 Jeep Cherokee): I suspect this van has vacuum-operated actuators which direct the air flow (that Jeep had three, and all went bad in the years we had it). So when engine vacuum changes as you drive, these actuators would change how they deflect the air.
Many more-modern vehicles have electric actuators which go bad too. Our 2014 Yukon has three of those, and in the 2 years we've had it, one actuator went bad. Same in our 2005 Yukon, and 1994 Suburban.
Of course! Completely forgot about vacuum actuators, thank you sooo much for the reply, makes perfect sense and explains it perfectly