95 740i--hot air from foot vent in the rear when AC is on

[kkodal78]

hi all
when i turn the ac it blows hot air in the rear vents.would anyone have any idea where to start looking to resolve this issue?thanks in advance

[Payback]

Do you feel any cold air coming from any of the other vents?

[kkodal78]

Do you feel any cold air coming from any of the other vents?

yes the dash vents all blow col air but i feel hot air coming from underneath the front seats where they have the fllor vents for the rear

[tberardi]

You should start by investigating the heater control valve as this is a very copmmon problem in these cars.
You can bypass the control valve by disconnecting the hoses in & out of the valve and reconnect with a piece of pipe, then run the car.
If the heat stops comming out then you know the control valve was the problem.
They fail in the normally open position and close on power.
If true, then the coils are probably shorted out due to corrosion.
You can repair by taking it appart and resolder the shorts in the coil or buy a new valve.
Otherwise, the stepper motors controlling the flaps may be faulty
Good luck.

[kkodal78]

thank you .i'll give it a shot tomorrow to see if it does the trick