I have been chasing an intermittent A/C problem with our 1996 960 for about three years. On a recent lengthy vacation trip, we suffered in 100 degree plus weather when the system quit, then later began cooling at a marginal rate.
Both of our Volvos (1990 780 & 1996 965) have the ACC automatic climate control. These systems work great until they don't. By comparing air flow between cars with an air velocity meter (with the A/C switched off) the maximum air flow from the 960 vents was approximately half that from those in the 780. Thus I suspect the fan control module as this transistorized module converts an audio frequency range variable-pulse-width signal to DC for the fan motor and replaces the simple tapped resistor found in other models. My suspicion is heightened because this module also controls the compressor, and because the comparable module in our 780 failed from aging with rather curious results some years back.
When the 780 module failed, I fortunately found a German owner had traced out the circuitry. The failure mode was leakage of an electrolytic capacitor used to convert pulses from the control computer to DC to operate a transistor that controlled the fan motor. Passing the raw, unfiltered, pulses resulted in a squealing sound I first attributed to motor bearings. Although the capacitor leakage damaged the circuit board and caused electrical leakage in an over-current safety circuit I was unable to clear, disabling this circuit and replacing the failed electrolytic capacitor restored proper operation.
I have been unable to locate Volvo part numbers for these modules on either the TASCA or usparts.volvocars.com sites, so am uncertain whether modules in the 780 and 960 are the same, or interchangeable. It would be nice to obtain some affordable spare units.
1996 960 ACC problem
1996 960 ACC problem
Jag har en polare som undrar och jag tankte att nan har nog vet svaret;