ok guys,

so i need your help. my wife has a 2006 honda civic 1.8 dx sedan. she has been throwing codes relating to the coolant sensors. well, i replaced both ECT sensors, and thermostat. The fan is not turning on. the AC fan turns on when ac is on. I have been googling and troubleshooting. i checked fan relay- it clicks. on the top ECT, i get voltage from the top ECT connector, i do not get it from the bottom ECT connector. I could not get the fan to turn on when the engine is up to temp. So just trying to figure it out i took both ECT connectors off and the fan turned on when the key was in the ON position. before i bring it to a shop can anyone help me figure out what the hell is going on.

thank you all for your help

 

The ECT sensor does not control the rad fan the ECT switch does, your car has an ECT switch, [for rad fan] an ECT sending unit, [for temp. gauge] and the ECT sensor, [for ECU] sounds like it was also bad.

Confirm fan is not the problem by supplying it power and ground directly from the batt. 94

 

On a 2006, there is no ECT switch.

There is an ECT sensor 1 and an ECT sensor 2. The PCM controls the fans, using input from ECT sensor 2

Extremely High Coolant Temperatures
In extremely high coolant temperature conditions
(Above 206
F (97
C) ), the ECM/PCM provides
ground to the coils of the A/C condenser fan relay,
the radiator fan relay, and the fan control relay
energizing them. Battery voltage is supplied to the
A/C condenser fan motor and radiator fan motor
through their respective energized relays, which
activates the motors at high speed.

A/C ON
The ECM/PCM detects that the A/C is ON through
an input from the A/C pressure sensor. Upon
receiving the A/C ON information, the ECM/PCM
provides ground to the coil of the radiator fan relay
energizing it. Battery voltage is supplied to the
radiator fan motor and A/C condenser fan motor in
series through the energized relay, which activates
the motors at low speed.