A/C Compressor - Continuous Engagement

90mazda06 Category U
Applicable Model/s 1988-89 626/MX-6
Subject CONTINUOUS A/C COMPRESSOR ENGAGEMENT
Bulletin No. 002/90
Issued 4/23/90
Revised

626/MX-6 Turbo Models:

626/MX-6 Non-Turbo Models:

DESCRIPTION

If the A/C compressor is engaged all the time -- even when the A/C and blower switches are OFF -- the ground circuit in the E.G.I. control unit may have been damaged by a surge current from the magnetic clutch or the cooling fan motor.

Continuous A/C compressor operation may cause evaporator freeze-up. Depending on the weather, it might take 30-60 minutes to freeze-up.

Although the surge current caused the E.C.U. damage, it has been found that the root of the cause is a faulty transistor installed in some control units.


TEST PROCEDURE

a) Connect the engine signal monitor (49 9200 162) and the adaptor harness (49 9200 163).

b) Set the selector switch and monitor switch to "1F."

c) Check the voltage at idle with the blower switch ON.

With the A/C switch ON, voltage should be below 2.5 V. With the A/C switch OFF, voltage should be 12 V.

d) If voltage readings are OK, the problem is in another component.


VIN OF PRODUCTION CHANGE

JM1GD****L1800000 (1990 Model) 1YVGD****L5100000 (1990 Model)




REPAIR PROCEDURE

If the "1F" voltage was incorrect, the E.C.U. has an internal failure. Replace the E.C.U. and the A/C relay (AC2-09).

Since the E.C.U. has not been modified, the A/C relay (AC2-09) should be replaced with a new, resistance-type relay. Used in the 1990 626/MX-6 models, the resistance-type relay prevents the surge current from flowing into the control unit.

The A/C relay (AC2-09) is located below the right headlamp. There are three relays in one place. Locate the A/C relay by referring to the wire colors illustrated.

PARTS INFORMATION


PART NUMBER DESCRIPTION
NEW OLD

H310 67 740 FB11 67 740 A/C Relay


WARRANTY INFORMATION

Warranty Type Code: A
Customer Comment Code: 60
Damage Code: 9W
Part No. of Main Cause: Use E.G.I. Control Unit Part No. (see attached charts)
Quantity: 1 pc.
Operation No: E.G.I Control Unit R&R - F0812X-R-X (0.4 Hr.) A/C Relay R&R - U0601X-R-X (0.3 Hr.)