1989 Dodge Dynasty Repair Question
Asked on July 15, 2011
Overheats, no radiator fan
1989 Dodge Dynasty LE overheats unless the A/C unit is ON . Radiator electric fan does not turn ON unless A/C is turned ON.
The ON position of A/C automatically sends an electrical signal to the electric radiator fan to start. I can verify signal with 12v test light.
If A/C is not turned ON , then no radiator fan , then engine temperature gauge gets extremely hot .
Highway driving allows sufficient air flow over radiator to cool the liquid engine coolant .
At city / local roads , red lights , stuck in traffic , engine temperature soars to HOT.
Why is electric fan not getting signal to turn ON ?
Electric radiator fan used to turn on after engine was turned off until engine would cool . This no longer occurs.
What happened?
Radiator Fan Relay is located on driver side engine bay fender. It passes 12v to radiator fan only when A/C is ON.
The ON position of A/C automatically sends an electrical signal to the electric radiator fan to start. I can verify signal with 12v test light.
If A/C is not turned ON , then no radiator fan , then engine temperature gauge gets extremely hot .
Highway driving allows sufficient air flow over radiator to cool the liquid engine coolant .
At city / local roads , red lights , stuck in traffic , engine temperature soars to HOT.
Why is electric fan not getting signal to turn ON ?
Electric radiator fan used to turn on after engine was turned off until engine would cool . This no longer occurs.
What happened?
Radiator Fan Relay is located on driver side engine bay fender. It passes 12v to radiator fan only when A/C is ON.
Asked by stilllearning6Answer
Replied on July 15, 2011
Recently installed : New thermostat, new temperature sending unit ( for gauge signal), new temperature sensor ( for MCU signal ) . Issue persists.
Replied on July 15, 2011
Unplug the two-wire coolant temperature sensor while the engine is idling. That should cause the fan to turn on.