3 L4-2.0L (2007)
Evaporator Temperature Sensor / Switch: Customer Interest
A/C - Stops Cooling After Long Drive When Hot/Humid
Bulletin No: 07-011/09
Last Issued: 09/18/2009
Subject:
A/C STOPS COOLING/REDUCED AIRFLOW DURING A LONG DRIVE IN HUMID TEMPERATURES
BULLETIN NOTE
^ This bulletin supersedes the previous bulletin 07-004/08 issued on 07/23/08. The APPLICABLE MODEL(S)/VINS and PARTS INFORMATION
have been revised.
^ Changes are noted below with a black change bar and/or asterisks.
APPLICABLE MODEL(S)/VINS
*2006 - 2009 Mazda3 vehicles (including Mazdaspeed3)
2006 - 2009 Mazda5 vehicles with VINs lower than JM1CR ****** 348679 (produced before November 1, 2008)*
DESCRIPTION
Some customers may report that with the A/C on during an extended drive, the vent air volume decreases and/or the vents start to blow warm air. This
could be result of the evaporator freezing, and it is most likely to occur while driving for an extended time at steady highway speeds with the A/C on
MAX in high humidity conditions. When the freeze-up occurs, the following symptoms may be present:
^ During freeze-up, the low pressure side pipe will have frost on it, giving the appearance it is frozen.
^ Allowing the evaporator to unfreeze will temporarily address the concern.
NOTE:
There are other conditions that can create similar symptoms, which include:
^ A/C cutoff control operation, where the PCM stops energizing the A/C relay when certain conditions are met. This can include the following
situations:
-
During acceleration (throttle valve opening angle 50% or more). The duration is 5 seconds.
-
When ECT (engine coolant temperature) is 113°C (235°F). The system repeatedly turns on and off every 20 seconds until the ECT is less than
approximately 110°C (230°F).
-
When ECT is 117°C (242°F) or more. The system will remain off until the ECT decreases to less than 114°C (237°F). These conditions signify the
engine is running hot and could be on the verge of overheating.
^ Electrical or mechanical concerns that could restrict vent air flow, causing irregular operation of the blower motor, and/or engagement of the A/C
compressor.
