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Home >> GMC >> 1991 >> Value Van 7.4 N >> Repair and Diagnosis >> External Pages >> Different car >> Section 35 (Engine Controls - Tests W/Codes - 3.9L) >> Self-Diagnostic Tests >> Test TC-37A - A/C Clutch Relay Circuit (DTC 33)

Test TC-37A - A/C Clutch Relay Circuit (DTC 33)

WARNING: This page is about a different car, the 1995 Dodge Ram Wagon, 1995 Dodge Ram Van, 1995 Dodge Pickup, 1995 Dodge Dakota, and 1995 Dodge Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: For circuit and connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS  section at the end of this article.
  1. Using scan tool, actuate A/C clutch relay. If A/C clutch relay is clicking, go to next step. If A/C clutch relay is not clicking, go to step 5).
  2. Condition required to set trouble code is not present at this time. A/C CLUTCH RELAY CIRCUIT trouble code sets if A/C clutch relay control circuit (Dark Blue/Orange wire) is not in its proper state when monitored by Powertrain Control Module (PCM). Possible causes are: open or short in A/C clutch relay coil windings, open or short in A/C clutch relay control circuit (Dark Blue/Orange wire), open or short in A/C clutch relay ignition switch output circuit (Dark Blue wire), or failed driver in PCM. Go to next step.
  3. Inspect all related wiring and connectors. Repair as necessary. Perform TEST VER-2. If no problems are found with wiring and connectors, go to next step.
  4. While still actuating A/C clutch relay, wiggle wiring harness from A/C clutch relay to PCM. If wiggling interrupts A/C clutch relay clicking, repair wiring harness as necessary. Perform TEST VER-2. If wiggling does not interrupt A/C clutch relay clicking, see INACTIVE TROUBLE CODE CONDITION . Perform TEST VER-2.
  5. Remove A/C clutch relay. Using scan tool in voltmeter mode, check voltage on A/C clutch relay connector, ignition switch output circuit (Dark Blue wire). If voltage is less than 10 volts, repair open Dark Blue wire or Yellow/Dark Green wire. Perform TEST VER-2.
  6. If voltage is more than 10 volts, use an external ohmmeter to check resistance across A/C clutch relay terminals. See Fig 1. If resistance is more than 100 ohms, replace A/C clutch re lay. Perform TEST VER-2. If resistance is less than 100 ohms, go to next step.
  7. Turn ignition off. Disconnect Powertrain Control Module (PCM) connector. Using scan tool in ohmmeter mode, check resistance of A/C clutch relay connector, control circuit (Dark Blue/Orange wire). If resistance is less than 5 ohms, repair short to ground in Dark Blue/Orange wire or Dark Blue/Red wire. Perform TEST VER-2.
  8. If resistance is more than 5 ohms, check resistance of control circuit (Dark Blue/Orange wire) between A/C clutch relay connector and PCM connector terminal No. 34 using an external ohmmeter. If resistance is more than 5 ohms, repair open Dark Blue/Orange wire or Dark Blue/Red wire. Perform TEST VER-2. If resistance is less than 5 ohms, replace PCM. Perform TEST VER-2.
Fig 1: Testing TC-37A Relay (All Models)
G94C31759