RA HVAC problem...too much hot air
Thread Starter
Evolving Member
Joined: Feb 2008
Posts: 120
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From: Toronto
RA HVAC problem...too much hot air
Just wondering if anyone is experiencing the same problem as I am with my RA's HVAC.
Basically when my HVAC temp dial is rotated a few clicks away from the coldest side (about 2-3 clicks), the temp of the air coming out of the vents is quite warm. When the dial is rotated to mid way between the coldest and middle setting, the air coming out is hot. I basically can't get any cool air coming from my vents. I either get cold (at the coldest setting) or hot. After about 45mins of normal driving the temperature will cool down a bit (dial at mid way point between coldest and middle).
The dealer cannot figure out the cause of this but does agree that it doesn't seem right. Its been like this for a long time now.
Any feedback would be appreciated.
Basically when my HVAC temp dial is rotated a few clicks away from the coldest side (about 2-3 clicks), the temp of the air coming out of the vents is quite warm. When the dial is rotated to mid way between the coldest and middle setting, the air coming out is hot. I basically can't get any cool air coming from my vents. I either get cold (at the coldest setting) or hot. After about 45mins of normal driving the temperature will cool down a bit (dial at mid way point between coldest and middle).
The dealer cannot figure out the cause of this but does agree that it doesn't seem right. Its been like this for a long time now.
Any feedback would be appreciated.
It's probably the Air Mixing Damper Control unit. Either that or it's the A/C ECU having problems. If it were the A/C ECU they probably would have been able to pull a DTC from the OBD.
Basically there is a damper with a motor that controls how much air flows over the heat exchanger to control the temperature and yours is ignoring the command to step to any position between open and closed which is why you can get full hot or full cold.
Basically there is a damper with a motor that controls how much air flows over the heat exchanger to control the temperature and yours is ignoring the command to step to any position between open and closed which is why you can get full hot or full cold.
i believe this is going to be because it's just like the HVAC on a house. The temperature dial does not change the temperature of the air that's being blown through the vents. It changes the temperature that the HVAC system targets the cabin temperature to be.
When the cabin temp is lower or higher than the target it changes which vents are being used, the fan speed, and switches between heating and cooling.
Assuming the engine is fully warmed and the AC system is fully primed, the temperature of the air coming through the vents will remain more or less constant...
When the cabin temp is lower or higher than the target it changes which vents are being used, the fan speed, and switches between heating and cooling.
Assuming the engine is fully warmed and the AC system is fully primed, the temperature of the air coming through the vents will remain more or less constant...
Thread Starter
Evolving Member
Joined: Feb 2008
Posts: 120
Likes: 0
From: Toronto
It's probably the Air Mixing Damper Control unit. Either that or it's the A/C ECU having problems. If it were the A/C ECU they probably would have been able to pull a DTC from the OBD.
Basically there is a damper with a motor that controls how much air flows over the heat exchanger to control the temperature and yours is ignoring the command to step to any position between open and closed which is why you can get full hot or full cold.
Basically there is a damper with a motor that controls how much air flows over the heat exchanger to control the temperature and yours is ignoring the command to step to any position between open and closed which is why you can get full hot or full cold.
The mechanic tried swapping HVAC ECU between mine and another one from an EVO that was working normal, and the same results in my car occured (too much hot air).* When mine was in the EVO the temp was ok.* Likewise I'm pretty sure any codes were checked.* The mechanic did mention that when he measured the potentiometer readings on my unit, the voltage drop wasn't dropping as it should of been.
Evolved Member
Joined: May 2009
Posts: 1,227
Likes: 4
From: NYC
Talk to Wanamaker. https://www.evolutionm.net/forums/9904713-post1.html
His car's blowing cold air, you guys should just switch cars.
His car's blowing cold air, you guys should just switch cars.
Newbie
Joined: Sep 2010
Posts: 47
Likes: 0
From: Oromocto
Talk to Wanamaker. https://www.evolutionm.net/forums/9904713-post1.html
His car's blowing cold air, you guys should just switch cars.
His car's blowing cold air, you guys should just switch cars.
