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Home >> GMC >> 1991 >> Value Van 7.4 N >> Repair and Diagnosis >> External Pages >> Different car >> Section 27 (Engine Controls - Tests W/Codes - 3.0L) >> Self-Diagnostic Tests >> Test TC-33A - High Speed Fan CTRL Relay Circuit (DTC 35)

Test TC-33A - High Speed Fan CTRL Relay Circuit (DTC 35)

WARNING: This page is about a different car, the 1995 Plymouth Voyager, 1995 Plymouth Grand Voyager, 1995 Dodge Grand Caravan, and 1995 Dodge Caravan. 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 diagrams, see WIRING DIAGRAMS  section.
  1. Using scan tool, erase DTCs. Using scan tool, actuate high speed radiator fan relay. If high speed radiator fan relay is clicking, go to next step. If high speed radiator fan relay is not clicking, go to step 5).
  2. At this time, condition required to set DTC is not present. HIGH SPEED RADIATOR FAN CTRL RELAY CIRCUIT DTC sets if an open or short is detected in high speed radiator fan relay control circuit. Possible causes are: open or shorted high speed radiator fan relay coil, open high speed radiator fan relay Dark Blue wire, open or shorted high speed radiator fan relay Yellow wire, or inoperative circuit driver in PCM. Go to next step.
  3. Inspect all related wiring and connectors and repair as necessary. Perform TEST VER-2. If no problems are found with wiring and connectors, go to next step.
  4. While still actuating high speed radiator fan relay, wiggle wiring harness from high speed radiator fan relay to PCM. If relay stops clicking while wiggling wiring harness, repair wiring and connectors as necessary. Perform TEST VER-2. If relay does not stop clicking while wiggling wiring harness, see INACTIVE DTC CONDITION  .
  5. Disconnect high speed radiator fan relay. Using scan tool in voltmeter mode, check voltage on high speed radiator fan relay connector Dark Blue/White wire. If voltage is less than 10 volts, repair open Dark Blue/White wire. Perform TEST VER-2. If voltage is more than 10 volts, go to next step.
  6. Using an external ohmmeter, check resistance between high speed radiator fan relay terminals. See Figure . If resistance is more than 100 ohms, replace high speed radiator fan relay. If resistance is less than 100 ohms, go to next step.
  7. Turn ignition off. Disconnect PCM connector. Using scan tool in ohmmeter mode, check resistance of high speed radiator fan relay connector Yellow wire. If resistance is less than 5 ohms, repair short to ground in Yellow wire. Perform TEST VER-2. If resistance is more than 5 ohms, go to next step.
  8. Using an external ohmmeter, check resistance of Yellow wire between high speed radiator fan relay connector and PCM connector terminal No. 55. If resistance is more than 5 ohms, repair open Yellow wire. Perform TEST VER-2. If resistance is less than 5 ohms, replace PCM. Perform TEST VER-2.
NOTE: A break in test sequence occurs at this point. Sequence skips from TEST TC-33A to TEST TC-38A. No tests have been omitted.
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