Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
A/C pressure switch -F129-: Functions
1996 Audi A4 Base, StandardSECTION Functions
WARNING: This page does not describe the selected car, but rather 15 other vehicles, including the 2005 Audi allroad, 2004 Audi allroad, 2004 Audi A6, 2003 Audi allroad, and 2003 Audi S6. However, it is still accessible from the selected car via links, so may be relevant.
- At low or high pressure in the refrigerant circuit the low/high pressure switch (switch between terminals 1 and 2) switches the compressor off (via A/C Control Head -E87-).
- Switching pressures (in bar high pressure):
- Switch open (compressor off):
Low pressure switch (opens at 1.2 bar and closes at 1.8 bar).
High pressure switch (opens at 30 bar and closes at 14.5 bar).
- Switch closed (compressor on):
1.2 (1.8) bar to 30 (14.5) bar.
- Switch open (compressor off):
- Switching pressures (in bar high pressure):
- Coolant Fan -V7- is switched to second speed via the high pressure switch (switch between contact 3 and 4).
- Switching pressures (in bar high pressure):
- Second speed of coolant fan engages at 16 bar (switch closes).
- Second speed of coolant fan is switched off at 12.5 bar (switch opens).
- Switching pressures (in bar high pressure):
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.