Thermo fan problem

[fozee]

Hey guys,

My Thermo fan isnt cutting in and its cause the car to overheat.

Can anyone give me some things to check so i can figure out what is at fault.

Cheers.

[ECU-MAN]

tell us what sort of car you have for more accurate info but the basics are.

look for the fues is it ok. try to find the temp switch, could be bolted on the bottom radiator tank or on the thermostat housing. when your %100 sure your looking at it unplug it and short it out. with the ignition switch on the fans should come on. if they do then the fault is more than likly in the thermo temp switch. if they do not come on then it could be the fan itself or wiring or a relay.

like I said before what car do you have as there are several different types of thermo fan circuits in various modles..

******pls note ozhonda nor myself take any responsibility by you shorting out the wrong sensor and doing damage to any system of your car *******

drive round with your air con on in the mean time as that will force the condensor fan to run which may help on some car

[fozee]

'99 civic GLi HB
D16Y donk all stock.

Ill check those thing directly tomorow morning.

[ECU-MAN]

there thermo fan temp switch should be mounted on the side of the head near the dizzy ( 90% sure )

turning on the aircon while driving wont do shit as the civics have mini radiators, the condensor fan doesnt covet the radiator at all.

another good test is to find the thermo fan relay in the underhood fuesbox ( next to the battery ) with the engine off and key in off position unplug it and bridge the two bigger pins. the fan should come on.

thermo fan switch sensor is the most common problem when fans dont kick in.

good luck with your test.

[fozee]

Thanks heaps Mr ECU-MAN
:thumbsup:

[ECU-MAN]

its ait, how did you go with your testing

[fozee]

I pulled the relay and saw no signs of arcing on the pins.
I have no wire around the place atm to bridge the pin recepticale in the relay box, so i will sort that tomorrow.

Aircon doesnt start the thermo fan either. Weather or not this is supposed to happen.
A mechanic told me today that when the aircon, in most Jap cars, is started the thermo is turned on to cope with the heat from the engine cause by the extra load.
I dont know if this is applicable with Hondas.

Can you point where the thermo fan sensor switch is exactly on the D16Y donk?
There is a sensor that is in the block just below the dizzy.
There is also a sensor on the Thermostat which i would have thought to do the same thing...
(have pics but waiting for WTDR to come back on line to host them)-


How can i replace this switch/sensor if its US or where can i find one?
Im guessing the only place that would stock these sort of Honda spares would probably be a Honda specific service depot or parts dealer, right?

[ECU-MAN]

you dont want to mix the thermo fan sensor with the ECT sensor.
to find out wich one is which get out the multi meter and mesure the reference voltage on both sensors , the ECT should be 5v and the thermo fan sensor will be 12v, ( does anyone know 100% wich one is which on the D16Y )

the air con test wont prove much as the reson most cars start the radiator fan as well as the condensore fan is to get max air flow across the condensor for maximum efficency . civic having a half size radiator is pointless to start the radiator fan as well as it will not help the condesor situation. Other honda vehicles with full length radiators also start the radiator fan as well as the condensor fan. An Australian sensor will work ok in a US car.

anyone got a manual for this car ????

[fozee]

US meaning Unservicable

I was told today that the temp gauge sensor comes out of the block.
So im guessing the sensor that is beneth the dizzy coming out of the block is most likely the Thermo Fan Temp Switch Sensor.

Not the one coming out of the thermostat...

[fozee]

All fixed thakns for your help!!!!

[ECU-MAN]

All fixed thakns for your help!!!!

what waz it ?????