A/C - Poor Performance
CATEGORYBody
SECTION
8
PAGE
88
ISSUE
08/94-0480
CODE
870
Subject:
Diagnosing AC Performance Complaints
Application:
1994- 900
Listed below are a number of procedures to follow when attempting to diagnose a customer complaint of poor AC performance.
Cars Affected:
All 1994 900 Models
Parts:
Anti-frost thermostat 46 32 956
Action:
1. First, make certain that:
^ the drive belt to the compressor is intact and does not slip.
^ the flow of air through the air ducts to the inside of the car are not obstructed.
^ the flow of air through the condenser is not obstructed.
^ the system pressures are correct.
^ there are no refrigerant leaks. Pay special attention to the areas noted in Figure 1.
^ you have done an AC system performance test as described on page 93 in Service Manual 8:3 Climate Control System, ACC.
2. After you have confirmed that all of the above have been done and specifications are correct, if the cooling performance is still poor it may be necessary to replace the anti-frost thermostat.
A new lower setting for the thermostat has been made with a cut-out temperature change from +36~F to +32~F (+ 2~C to 0~C). This new part is P/N 46 32 956. Make certain after replacing the thermostat that a performance test is again run.
3. If replacement of the anti-frost thermostat does not alleviate the AC performance complaint, then:
a. measure the temperature in the center panel outlet using a digital thermometer at a depth of 100 mm. Measure the temperature in the outlet on the front passenger side in the same way.
b. check the difference in temperature between the two outlets
1. if the difference is always less than 4~F (2~C) = ok
2. if the difference is occasionally more than 4~F (2~C) = ok
3. if the difference is consistently greater than 4~F (2~C), then you must adjust the heat flap. Follow directions below.
4. Adjustment of the heater flap:
Adjustment of the heater flap can be done at the lower end of the control cable and by changing the temperature lever arm in the control unit. See PSI 05/94-0468.
The lower end of the cable protection should be adjusted according to Figure 2 when the temperature knob is set to cool. A new, stiffer cable (single stranded cord) should be used. This change was introduced into production as of VIN Serial No. R2017502.
Other improvements referenced in earlier PSI'S:
5. Improved climate control panel (manual heating and ventilation) now available:
The control panel has a redesigned lever arm as discussed in PSI 05/94-0468. The end stop settings for the temperature knob have also been made more positive. Make certain the correct lever arm has been installed. This change was introduced into 900S production as of VIN Serial No. R2031177.
6. Elimination of air leakage:
To eliminate the risk of air leakage at the air blending flap, the upper and lower parts of the HVAC unit should be screwed together per PSI 05/94-0468. This change was introduced into production as of VIN Serial No. R2020606.
Warranty Information:
A warranty claim may be submitted for a customer complaint of A/C cooling performance.
The following information must be provided on the claim:
Failure Code: 87020-71-W1-05.
Labor Operation No.: 87014 for 1.0 hr. - Ck A/C performance.
87062 for 0.4 hr. - Repl. anti-frost switch.
Straight Time: 87099 Max. 0.6 hr. - procedures 4-6 (if necessary)
Please update your DCS tables with the following information:
Labor Operation
87014 - Ck A/C performance
M94 900 hrs. 1.0
Engine type 9
Trans. type B
Begin and end year 94