A/C Evaporator - Low Air Flow from Vents, Poor Cooling
89mazda10Category 16
Applicable Model/s 1986-87 626
Subject A/C FREEZE-UP
Bulletin No. 045/89
Issued 12/29/89
Revised
DESCRIPTION
When a customer complains of the following items, the vehicle is probably experiencing A/C evaporator icing or freeze up.
1. Decrease in air flow from the A/C vents after a short period of time.
2. A/C cools well only for the first few minutes of operation. (Depending on the weather condition, it may take 30-60 minutes to freeze up.)
To confirm a customer complaint, dealers are requested to make sure that the compressor does not cycle after a short period of time.
To correct this, the thermistor probe should be replaced with the thermostat.
NOTE:
If the compressor does cycle and there is insufficient cooling, the heater mixture door could be partially open. Check and adjust it in accordance with Service Bulletin Category 16, 022/87.
PARTS INFORMATION
To replace the thermistor with the thermostat, the following parts are necessary.
REPLACEMENT PROCEDURE
1. Move the temperature control lever to the full left position.
2. Remove the glove box and liner.
3. Lower the under-dash cover.
4. Remove the lower side of the left seal plate.
5. Loosen the right side seal plate and slide to the right.
6. Unplug the connectors to the control box and the thermistor.
7. Detach the harness from the clip on the bottom side of the evaporator case.
8. Remove the control box and relay (if installed at this location).
9. Remove the upper and lower flange nuts (6 mm) which are used to mount the evaporator case.
10. Pull the evaporator mounting brackets away from the studs.
11. Remove four (4) clips on the evaporator case.
12. Separate the upper and lower cases.
13. Within the inside of the evaporator case, cut the harness of the thermistor probe off and discard it.
14. Install new thermostat capillary tube 5 mm below the thermistor probe to a depth of approximately 2" or 50 mm.
15. Route the capillary tube through the same hole in the evaporator case as the thermistor probe.
16. Reinstall the evaporator case clips. BE CAREFUL NOT TO PINCH THE CAPILLARY TUBE.
17. Mount the thermostat and the control box. BE CAREFUL NOT TO INTERFERE THE CAPILLARY TUBE WITH OTHER PARTS.
NOTE:
Reinstall relay to control box if previously removed.
18. Reinstall the upper and lower 6 mm flange nuts and seal plates.
19. Wiring of the thermostat.
a) If the vehicle is 1986 model or 1987 MTX, perform the following procedure.
1) Disconnect the G-15 coupler located under the evaporator case.
2) Release the Red/Black (RB) male wire terminal from the G-15 coupler.
3) Connect the RB wire to the thermostat harness using the single pin couplers supplied.
4) Insert male terminal of thermostat harness into G-15 coupler as shown.
5) Reconnect the G-15 coupler.
6) Connect the harness to the thermostat.
7) Connect the short-circuited coupler to the thermistor connector on vehicle harness.
8) Tape the short-circuited coupler to the vehicle's harness.
NOTE:
Be sure harness does not interfere with surrounding parts.
9) Reconnect the control box connector.
b) If the vehicle is a 1987 ATX, perform the following procedure. (See illustration next page)
1) Disconnect the relay coupler consisting of the following wires:
Red/Black (RB) Yellow/Green (YG) Green (G)
NOTE:
This relay coupler may be located on a relay which is installed onto the blower motor. If so, remove this coupler and install the coupler which is located next to the control box. (See illustration next page).
2) Release the Red/Black (RB) wire terminal from the relay coupler.
3) Connect the RB wire to thermostat harness using the single pin couplers supplied.
4) Insert the female terminal of the thermostat harness into the relay coupler.
NOTE:
Be sure that the female terminal is positioned into the center opening on relay coupler.
5) Reconnect the coupler to the relay.
6) Connect the harness to the thermostat, (2) couplers.
7) Connect the short-circuited coupler to the thermistor connector on vehicle harness.
8) Tape the short-circuited coupler to the vehicle harness.
NOTE:
Be sure harness does not interfere with surrounding parts.
9) Reconnect the control box connector.
20. Secure harness to bottom of evaporator case using clip.
21. Operate the vehicle and verify that the air conditioning system is operating properly.
22. Reinstall the liner, glove box and the under-dash cover.
WARRANTY INFORMATION
Customer Comment Code: A1
Damage Code: AB
Process Number: J7002B
Part Number of Main Cause: 0000-67-B93A-6P Qty 1
Related Part Number: 0000-67-S00A-8C Qty 1
Operation Number: YY0002RX
Labor Hours: 0.5 Hrs