Volvo Maintenance Hints for 7xx/9xx - Bill Garland's Nuclear ...

Blower Motor:
2-3-3 Starting current too high, motor seizes or A
turns sluggishly
Power terminal incorrectly connected to
12 V for the solenoids as follows:
2-4-1 Water valve A
2-4-2 Bi-level A
2-4-3 Vent A
2-4-4 Recirculation A
2-4-5 Defroster A
2-4-6 Floor A
2-4-7 Maximum blower relay A
2-4-8 Compressor A
2-4-9 Blower relay (cars with air conditioning) A
2-4-9 Engine cooling fan relay (cars without a/c) A
Vacuum Servos:
Panel Vent Stops Working Upon Acceleration.
General Notes. [Inquiry:] My friend has a '94 960 and the air stops blowing from the vents while
the car is accelerating (the a/c fan is still spinning but no air is coming out) when ever the car
reaches a steady speed it starts blowing again. The same thing happened to me in an '90 760t
and it turned out to be a hole in the vacuum line that goes to the vacuum reservoir. However I
can't locate the reservoir in this car. Does anyone have any ideas?
General Diagnostics. This is usually a result of a vacuum leak, whether it be an interior hose or
servo motor, in the engine compartment, or at the vacuum reservoir. Find the vacuum line that
goes to the vent diaphragm (vacuum bellows) under the dash behind the steering wheel. Uplug
it and stick a vacuum gauge into the line using a "T". The vacuum should read engine vacuum
at idle. Then accelerate the engine: if vacuum drops, your vacuum check valve may be bad. The
vacuum gauge should keep a high vacuum reading when you accelerate. If the check valve and
tubing under the hood are fine and the vacuum reading still drops, you have a leak under the
dash, most likely one of the 4 bellows. The electronic solenoids and the vacuum reservoir