Diagnostic Aids
Perform this test when instructed during QUICK TEST or other test step. This test is only intended to diagnose the following:
- A/C relay.
- Clutch Cycling Pressure (CCP) switch.
- High Pressure Switch (HPS).
- Blower motor switch.
- Harness circuits (ACR, ACS, CCPS, HPS and BLMT).
- PCM.
CIRCUIT PIN IDENTIFICATION
| Circuit | Breakout Box Pin No. | PCM Pin | Wire Color |
|---|---|---|---|
| ACR | 12 | C1-4 | Green/Black |
| CCPS | 4 | C1-22 | Pink/Black |
| BLMT | 10 | C1-16 | Yellow/Black |
| HPS | 17 | C1-6 | Pink/Yellow |
NOTE:
For A/C relay or WAC relay faults, start testing at step 1). For other concerns, start testing at step 10).
- 1) Check Power To Relay Turn ignition off. Disconnect A/C relay. Turn ignition on. Measure voltage of PWR circuit at relay harness connector. If voltage is greater than 10 volts, go to next step. If voltage is less than 10 volts, repair open PWR circuit. Restore all electrical connections and repeat QUICK TEST .
- 2) Perform Relay Click Test Turn ignition off. Disconnect PCM and inspect connector for damage. Install breakout box (leave PCM disconnected). Turn ignition on. Ground breakout box test pin ACR or WAC. If relay clicks when grounded, replace PCM. Restore all electrical connections and repeat QUICK TEST . If relay does not click, go to next step.
- 3) Check ACR Or WAC Circuit For Open Turn ignition off. Install breakout box (leave PCM disconnected). Disconnect A/C or WAC relay. Measure resistance between breakout box test pin ACR or WAC and corresponding circuit at relay harness connector. If resistance is less than 5 ohms, go to next step. If resistance is greater than 5 ohms, repair open ACR or WAC circuit.
- 4) Check ACR Or WAC Circuit For Short
Turn ignition off. Install breakout box (leave PCM disconnected). Disconnect A/C or WAC relay. Measure resistance between breakout box test pin ACR or WAC and ground. If resistance is greater than 10,000 ohms, replace relay. Restore all electrical connections and repeat QUICK TEST . If resistance is less than 10,000 ohms, repair short to ground in ACR or WAC circuit. Restore all electrical connections and repeat QUICK TEST .NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 4) to step 10). No test procedures have been omitted.
- 10) Check Ground At Switch Turn ignition off. Disconnect switch in question. Measure resistance between ground terminal at switch harness connector and chassis ground. If resistance is less than 5 ohms, go to next step. If resistance is greater than 5 ohms, repair open ground circuit. Restore all electrical connections and repeat QUICK TEST .
- 11) Check Signal Circuit For Open Turn ignition off. Disconnect switch in question. Install breakout box (leave PCM disconnected). Measure resistance between appropriate breakout box test pin and signal circuit at switch in question. If resistance is less than 5 ohms, go to next step. If resistance is greater than 5 ohms, repair open signal circuit. Restore all electrical connections and repeat QUICK TEST .
- 12) Check Signal Circuit For Short Turn ignition off. Disconnect switch in question. Install breakout box (leave PCM disconnected). Measure resistance between appropriate breakout box test pin and ground. If resistance is greater than 10,000 ohms, go to next step. If resistance is less than 10,000 ohms, repair short to ground in signal circuit. Restore all electrical connections and repeat QUICK TEST .
- 13) Check Switch See A/C-HEATER SYSTEM article, for switch testing procedures. Replace switch as necessary. If switch tests okay, and no problem is found with circuit, replace PCM. Restore all electrical connections and repeat QUICK TEST .