Question about 2001 Honda Civic
The radiator fan not running unless I put it on a/c and it will go back n forth from "H" to 1/2 way down and the heat runs hot and cold.
The fan won't come on because the thermoswitch is in the bottom of the radiator, without coolant flow the switch never gets hot. Just because a part is new doesn't mean it is good, is the thermostat an aftermarket part ? I would take out the thermostat (leave the gasket) and see if the bottom hose gets warm. If the bottom hose does not get warm, you may have a blockage or bad water pump
Posted on Apr 18, 2009
Since warm air eventually comes out when the vehicle is in motion, you may have an air mix door that is stuck in fresh or is somehow blocking warm air from the heater core.
To see if the air mix control motor is bad, you need to retrieve your Diagnostic trouble codes (DTC's) from the heater control panel. To run the diagnostic function, do the following:
1. Turn the ignition switch ON (II).
2. Turn the fan switch OFF.
3. Press the recirc control button to select Recirc (recirc light on.)
4. Press and hold the recirc button to select Fresh (recirc light off) and continue to hold the button down until the recirc light comes on for two seconds and then goes off.
5. If the system is okay, the recirc light stays off.
6. If there is a problem, the recirc light blinks the DTC to indicate the trouble. One blink=a problem in the air mix control motor circuit. Two blinks=problem in the mode control motor circuit
Three blinks=problem in evaporator temp sensor circuit.
7. Turn the ignition switch off to cancel the self diagnosis function. Run the diagnostic again after repairs are complete.
Note: the air mix control motor has a rod which connects to a plastic link. The link controls the mix doors and also connects to the heater control water valve via a cable. The air mix motor may check okay, but if the link is broken then you will still have problems. the motor is on the bottom of the heater unit in the front passenger's foot well.
Posted on May 11, 2009
It will most likely be a Thermos fan switch if you go to parts store git a new one they can point out to you where it is located ,most of the time they are in the head near the thermostat ,but some times they are in the radiator hope this helps . IT could also be the relay,you could ground the thermo fan switch it should cause the fan to run then you will know that the relay is OK ,hope this is some help ,feel free to ask if we can be of any further assistance Thank you.
Posted on Mar 30, 2010
iam suspecting the temperature gauge here ,something is or could be wrong with its electrical conductivity ,or the cooling fan is coming on too late which could be caused by a similar problem with the fan temperature switch
Posted on Feb 15, 2011
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