How to Troubleshoot the Radiator Fan on a 1994 Honda Civic 1.6L

Honda released the Civic in the 1973 model year, as a subcompact yet roomy vehicle. Throughout its lifespan, the Civic has seen eight generational changes. Some changes were fairly modest, while others involved a complete redesign. The Civic has now become a symbol of longevity and reliability in the automotive world. The 1994 Honda Civic came standard with a 70-horsepower, 1.5-liter, four-cylinder engine. The largest and most powerful engine on the 1994 Civic was the 1.6-liter, four-cylinder that produced 125 horsepower. When the radiator fan stops working in the 1994 Civic, you must troubleshoot the fan to repair it correctly the first time.

Things You'll Need

  • 2 jumper wires
  • Multimeter
  • Combination wrench
  • 1-quart sauce pan
  • Clean water
  • Stove
  • Digital thermometer
  • String
  • Pull fuse number 13, the radiator fan fuse, from the under-hood relay and fuse box and check the metal filament inside the fuse. If the filament is broken, replace the fuse and recheck the fan. If the filament is in one piece, reinstall the fuse and continue with the diagnostics.

  • Disconnect the plug from the rear of the radiator fan motor. Run one jumper wire from the positive battery terminal to positive prong on the fan motor's receptacle -- the one the blue wire connects to. Run another jumper wire from the negative terminal on the battery to the other prong in the fan motor receptacle.

  • Watch for the fan to begin moving. If it fails to run, replace the fan motor and retest the fan. If it runs, continue with diagnostics.

  • Remove the radiator fan relay, located in the under-hood relay and fuse box on the passenger's side inner fender. Read the circuit map to identify the switch side and the power side, the power side has one constant line connected to a coil-like line. The switch side has a broken line.

  • Connect power and ground to the two prongs on the power side of the relay and test for continuity between the two prongs on the switch side, using a multimeter. If no continuity exists, replace the relay and retest. If there is continuity, reinstall the relay and continue with the diagnostics.

  • Locate the coolant temperature sensor; it is located on the front of the engine, next to the distributor. Place a drain pan under the coolant temperature sensor. Disconnect the wiring harness from the coolant temperature sensor and remove the temperature sensor from the engine with a combination wrench.

  • Fill a saucepan with clean water. Place the pan on a stove.

  • Connect multimeter test probes to the two prongs on top of the coolant temperature sensor. Suspend a digital thermometer and the sensor in the saucepan with a piece of string. This prevents them from touching the bottom of the pan and creating an inaccurate reading.

  • Turn the stove on to heat the coolant in the pan, while checking the continuity between the two prongs on the temperature sensor. There should be no continuity between the two prongs until the coolant temperature reaches about 191 degrees F. From 191 degrees F and up, continuity should exist.

  • Replace the sensor if it fails the continuity test and recheck the system. If the sensor passes the continuity test, the problem is within the Civic's wiring. Check and repair all broken power and ground wires.