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2014 RAM 2500
6.7L I6 Cummins Diesel•4WD•AUTOMATIC•diesel•turbo
16 active safety recalls on this vehicle — view recalls🏆Sponsored by Lost Pines Precision Automotive· Bastrop, TX
Repairs436Labor519Torque3583Fluid10DTC1037Battery1Maintenance0Recalls16
P1490moderate severityPowertrain

Low Speed Fan CTRL Relay Circuit

on 2014 Ram 2500 6.7L I6 Cummins Diesel · 4WD

What this code means

The PCM has detected a malfunction in the low-speed cooling fan relay control circuit. The relay that runs the cooling fan at low speed for normal cooling is not functioning properly.

Symptoms

  • Check Engine Light
  • Engine running warmer than normal
  • Cooling fan does not run at low speed
  • Fan only runs at high speed or not at all

Common causes

  • Faulty low-speed fan relay
  • Fan resistor or module failure
  • Wiring issue in relay circuit
  • Corroded relay socket contacts
  • PCM driver circuit malfunction

Diagnostic steps

  1. Test low-speed fan relay by swapping with identical relay
  2. Check relay socket for proper voltages
  3. Test fan resistor or speed control module
  4. Inspect wiring for opens or shorts
  5. Check PCM control output

Repair notes

Replace the low-speed fan relay or fan resistor module; repair wiring if damaged.

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