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Auxiliary Blower Motor Operates In High Speed Only

  1. Perform BLOWER CONTROLS SYSTEM CHECK . Go to next step.
  2. Disconnect auxiliary blower motor resistor connector. Connect a fused jumper wire between terminals "A" (Light Blue wire) and "B" (Yellow wire). See WIRING DIAGRAMS . Turn front auxiliary A/C-heater control assembly to medium position. If auxiliary blower motor turns on, go to next step. If auxiliary blower motor does not turn on, go to step  4.
  3. Replace auxiliary blower motor resistor. See AUXILIARY BLOWER MOTOR & FAN  under REMOVAL & INSTALLATION. Go to BLOWER CONTROLS SYSTEM CHECK .
  4. Disconnect auxiliary blower motor connector. Use a DVOM to check for continuity in Yellow wire between auxiliary blower motor resistor connector terminal "B" and auxiliary blower motor connector terminal "A". If continuity is indicated, go to step  6. If continuity is not indicated, go to next step.
  5. Repair open in Yellow wire between auxiliary blower motor resistor and splice S402. Splice S402 is located approximately 2.5" (7 cm) from blower motor resistor harness breakout, going toward relays. Go to BLOWER CONTROLS SYSTEM CHECK .
  6. Reconnect all disconnected components. Remove both auxiliary blower motor low and medium speed relays. Connect fused jumper wires between both relay cavity terminals No. 2 and 5. Turn front auxiliary A/C-heater control assembly blower switch to low and medium positions. If blower motor operates in both positions, go to step  10. If blower motor does not operate in both positions, go to next step.
  7. Disconnect front and rear auxiliary A/C-heater control assemblies. With negative lead of DVOM connected to terminal "B" of front auxiliary A/C-heater control assembly, check for continuity at terminals "C" and "E" with switch in low and medium positions. With negative lead of DVOM connected to terminal "F" of rear auxiliary A/C-heater control assembly, check for continuity at terminals "C" and "E" with switch in low and medium positions. If continuity is indicated in both positions, go to step  9. If continuity is not indicated in both positions, go to next step.
  8. Replace faulty auxiliary A/C-heater control assembly. See AUXILIARY A/C-HEATER CONTROL ASSEMBLIES  under REMOVAL & INSTALLATION. Go to BLOWER CONTROLS SYSTEM CHECK .
  9. Repair open in suspect relay circuit between cavity terminal No. 2 and auxiliary A/C-heater control assembly connector. Go to BLOWER CONTROLS SYSTEM CHECK .
  10. Replace auxiliary blower motor low and medium speed relays. Go to BLOWER CONTROLS SYSTEM CHECK .
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