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Home >> GMC >> 1991 >> Value Van 7.4 N >> Repair and Diagnosis >> External Pages >> Different car >> Section 29 (Engine Controls - Tests W/Codes - 3.3L Gasoline) >> Self-Diagnostic Tests >> Test TC-29A - High Speed Fan Control Relay Circuit (DTC 35)

Test TC-29A - High Speed Fan Control 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 at the end of this article.
  1. Using scan tool, erase DTCs and actuate high speed radiator fan relay. If high speed radiator fan relay is not clicking, go to step 5). If high speed radiator fan relay is clicking, go to next step.
  2. Condition required to set DTC is not present at this time. The HIGH SPEED FAN CONTROL RELAY CIRCUIT DTC sets if high speed radiator fan relay control circuit (Yellow wire) is not in its proper state when monitored by Powertrain Control Module (PCM). Possible causes are: open or shorted high speed radiator fan relay coil windings, open or shorted high speed radiator fan relay control circuit (Yellow wire), open or shorted high speed radiator fan relay ignition feed circuit (Dark Blue/White wire), or failed 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 radiator fan relay to PCM. Stop actuation of high speed radiator fan relay. Using scan tool, read DTCs. If HIGH SPEED FAN CONTROL RELAY CIRCUIT DTC returns, repair wiring harness as necessary. Perform TEST VER-2. If HIGH SPEED FAN CONTROL RELAY CIRCUIT DTC does not return, system is now functioning properly. Perform TEST VER-2.
  5. Remove high speed radiator fan relay. Install a known-good high speed radiator fan relay. If known-good high speed radiator fan relay is clicking, replace original high speed radiator fan relay. Perform TEST VER-2. If known-good high speed radiator fan relay is not clicking, remove known-good high speed radiator fan relay. Put scan tool in voltmeter mode.
  6. Using scan tool, check voltage on high speed radiator fan relay connector ignition feed circuit (Dark Blue/White wire). If voltage is less than 10 volts, repair open Dark Blue/White wire. Perform TEST VER-2.
  7. If voltage is more than 10 volts, check resistance between high speed radiator fan relay terminals using an external ohmmeter. 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.
  8. Turn ignition off. Disconnect Powertrain Control Module (PCM). Using scan tool in ohmmeter mode, check resistance of high speed radiator fan relay connector control circuit (Yellow wire). If resistance is less than 5 ohms, repair short to ground in Yellow wire. Perform TEST VER-2.
  9. If resistance is more than 5 ohms, using an external ohmmeter, check resistance of control circuit (Yellow wire) between 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.
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