What are the symptoms of Hissing from vents and slow loss of refrigerant in Ford Mustang?

Weak cabin cooling. Air conditioning works intermittently. Unusual noises when A/C is turned on

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Hissing from vents and slow loss of refrigerant

Q: How to fix Hissing from vents and slow loss of refrigerant in Ford Mustang?

Material defect in the evaporator core. Some crack at the welds due to thermal expansion cycles, causing leaks that are difficult to diagnose. The procedure in TSB 18-2256 specifies to replace only the (improved) evaporator without removing the external control housing. The replacement takes the mechanic 8 to 12 hours of work due to the need to remove the dashboard.

in Ford Mustang (2015-2017)

Symptoms

Weak cabin cooling
Air conditioning works intermittently
Unusual noises when A/C is turned on

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Technical diagnosis (Premium)

Recognized technical fault:

Auxiliary controller voltage instability detected

Technical analysis

Detailed analysis of HVAC controller operation parameters, CAN bus data readings, and diagnostic signal waveforms. Purchase PRO access or log in to read the full fault analysis.

Confirmed solution

Complete step-by-step repair procedure including module non-volatile memory reset, sensor calibration, and correct wiring routing. Unlock the full report to see the instruction.

Parts needed

Filters ferrite anti-interference / noise suppressor
Auxiliary starting battery (depending on cell status)

Workshop hacks

Important workshop tips for mechanics regarding bypasses without expensive control module replacement and manufacturer software service bulletins.

TSB / TPI service bulletins

TSB-24-HVAC-01TPI-2068943/2

A/C Technical Specifications

Standard

Refrigerant: R1234yf Amount (g): 600g Oil: WSS-M2C300-A2 PAO 68 AA1 lub PAG ISO 46 YF Oil (ml): 100ml

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Hissing from vents and slow loss of refrigerant

Symptoms

A/C Technical Specifications

Other problems in Mustang

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