You don't say whether the fan starts and shuts off with the bumps, or
the heat goes cold but the fan stays on. If it's the fan shutting off
and coming back, you most likely have an intermittent connection to the
blower motor somewhere at the fuse box, the fan speed control
switch or the fan motor, or a loose ground connection at the fan motor.
The fan motor is visible under the right side speaker grille on
the dash. Make sure you re-connect the short black corrugated hose to
the grill vent or you won't have defrosting on that side!
The air distribution rotary switch controls where the air goes. The fan
speed switch controls exactly that: fan speed. the temp rotary switch
controls the coolant temp into the heater core. You need to clarify what
you mean by "Also, the dash controls
for the vents won't allow me to turn up the
You might also have one or more of the
- is you vacuum tank properly connected and are there
leaks in the vacuum piping? The tank is in the driver side rear wheel
well below the trunk deck on a convertible, and in the passenger side
front fender area on the other cars. It's a white bottle with one or two
hoses connected to it. If not properly on, your vacuum operated heater
flaps won't move. Does the air distribution knob make sucking or hissing
noises when you set it to different positions? If not, check the tank
connections, look for vacuum line leaks, then suspect the vacuum valve
behind the distribution knob.
- if the air distribution rotary switch makes noises
when you change its setting, but nothing happens, then suspect the
vacuum solenoids that open and close the heater flaps - could be a loose
vacuum line or a defective vacuum solenoid
- the shaft connecting the temp control knob to
the heater valve behind it may not be properly in place. This can be
and adjusted if necessary, from the left side speaker/vent cutout on
top of the
dash. Make sure you re-connect the black flex hose to the air vent tube,
or you'll get no defrosting afterwards!
the centre vents always blow
cold air; a brilliant idea from Saab so the driver (and passenger) can
get fresh air in the face and stay awake while the rest of the driver,
passenger and car is toasty!