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ridgerunner 08-04-2008 08:21 PM

83 240d a/c ?'s
I would like some input as to why my a/c will blow cold out the two center vents but the two on the side (one on pass, one on drivers side) are real hot air like the heat is on.
Anyone had this problem?

Graminal95 08-04-2008 09:11 PM

The center vents are just that and will only blow outside air or a/c air. All other vents work with the heater controls for temperature. So I would check to make sure that you have both heater control knobs set to off or the arrow pointing down. If they are in the off position you might need a new heater control valve, or adjustment on the heater control knobs.

Scott98 08-04-2008 09:35 PM

I get cold air out of all 4 with A/C. I get hot air on the outside two but cold (outside) air out of the middle two with the heat on.


ridgerunner 08-04-2008 10:21 PM

Ok, the two heat control knobs are definetly off, (pointed down). The air I get out of the two center vents are cooler than outside air. Where exactly is the heat control valve? Is it the valve on the firewall that has a couple cables that attach to it?
Is it possible to bypass that valve for the summer?

dmorrison 08-05-2008 12:39 PM

Sounds like your hot water control valve in the engine compartment is either disconnected or leaking.
Move the heat control knobs and check the movement of the 2 levers on the valve. Also make sure the levers on the valve are actually moving. If one or both are not moving the valve correctly then you will have heat.
If they are moving correctly then feel the hoses on the engine side of the valve vs. the passenger compartment side. If the passenger side is as hot as the engine side, with the valves off then the valve is leaking.
If the valve is working correctly then there is a possibility that the main flap in the evaporator box is not working correctly and hot outside air is entering the system.
More than likely it is the water valve.


Graminal95 08-05-2008 08:20 PM

Follow what Dave said and if i you need to you can put a valve inline after the heater control value.

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