Volkswagen Golf 1999 Service Manual page 3886

A/C refrigerant system, servicing
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-F129- functional checks
To determine proper A/C system performance,
perform the following functional checks with the
switch installed and connected.
- With the engine running, briefly bridge terminal 1
and 2 of connector. If the A/C clutch -N25-
engages, the refrigerant circuit is empty.
- Check refrigerant capacity (fill). If system
pressure is too low (refrigerant leakage), -F129-
switches A/C clutch off.
- Check cooling fan function. When system
pressure increases, -F129- causes coolant fan -
V7- to switch to next higher fan speed.
- Check if A/C system switches off. At excessive
system pressures (e.g.: caused by high ambient
temperatures or if condensor is blocked), -F129-
switches A/C clutch off.
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13/2/2005