VZ thermo fan issues

[azazeldeath]

I found out why my car was running hot one night when I was doped up on my painkillers (for my back). Turns out the fans will not kick in at all no matter how hot it gets but the second I turn my aircon on both kick in.

Is there some relay or sensor I can replace to fix it? Or some way to make them turn on when the car does regardless of the temperature?

I tried a search too many VZ overheating problems that involve the thermostat or unbled systems to find anything on this topic.

Thanks.

[leethal1]

the thermo fans on the car are controlled by the ecu, there are no seperate tempreature and ac relays, only high and low relays which are controlled by ecu. the ac pressure sender tells the ecu to turn fans on and the tempreature sensor should do the same. i would recommend a checking or replacing your coolant temp sensor - there normally is a gauge one and a seperate one for the ecu. does the car run ok? is it chewing through a little too much fuel? these could be indicators of a faulty sensor.


if you know someone with a cheap obd2 tool you can check your ecu coolant temp quite easily.

[azazeldeath]

I have an OBD2 scanner, it goes through a fair bit of fuel but it has been doing that since the exhaust, extractors, CAI, and a few other mods. The car runs fine, starts first go. Idles very smooth with about 25RPM variation at most.

Where is the sensor located?

[impulsive]

there is a relay in the engine bay isnt there?

[azazeldeath]

not that I can see

[leethal1]

if the fans come on with the a/c it's not a issue with the relay's issue, however if you want to check swap the low fan (smaller engine fan relay) with another one in the box near the battery (there are 2 fan relays, High and low speed)
there are only 2 options are really left - ecu U/S or the coolant temp sensor has issues, maybe even just unplugged when mods were made, do you have one of thise bluetooth obd2 scanners? torque is a good program, I think it reads the engine coolant temp from the ecu and not the temp gauge, is there any fault codes logged? the coolant temp sensor is located under the intake runners on the passenger side see link - http://drivemycar.com.au/pdfs/VZCommodoreDCL.pdf

The higher fuel consumptoin seems to say the car is running on a cold coolant temp setting ie - like a choke on an older car

[azazeldeath]

I have one of the handheld OBD2 scanners, no error codes at all. It only started doing it after I paid a very dodgey mechanic to replace my coil packs (while getting a rebuild). Blew up one radiator already.

I will see if its unplugged later tonight and let you know how it goes. Thank you very much for your expertise though.