over heating

[geardys]

G'day guys.
My brother has a 91 vg Ute (v6) that over heats when its not moving, but on the road it runs at the right temp.
We have replace the water pump, thermostat, flushed the coolant, changed both the temp sender and sensor but it's still over heating and the fan doesn’t come on. The relay works fine and there isn't a blown fuse and the fan works when connected to an external power supply. So does anybody have a suggestion for a fault?
maybe the wiring???
Thanks

[PaRaDoX]

i know this may sound silly, but check the memcal?? maybe swap it, because isnt the thermo fan controlled by that???

maybe check the thermostat wiring

does the fan go on at all?? or constantly stay off?? if its always off check the wiring of the fan

[pandaman]

Umm, I know F'all about V6 commos but if the engine is overheating at idle the problem is most likely lack of airflow, as you've found the thermofan aint working i'd say you've found why. I'd also guess that the reason is likely to be a dud connection, a fault within the memcal itself isn't very likely, i'd reccomend tracing the wiring looking for a break/dodgy joint. Might be helpful if you could find a wiring diagram for it to work out where a fault might be.

[Full Spectrum]

Can the ECU control when the fan kicks in? I would like myn to kick more in when it's stop start driving, My sisters Fan on her new car comes on when the car sits in the one spot for 10sec.

[geardys]

the ecu control when the fan is turned on by the amount of voltage its sent by the temp sender, but i don't think that its the ecu/'chip'.
i've got the wiring diagrams and i guess its going to come down to that. or i can get an after market switch that u can controll the temp that it come on to ur self and fix it that way.
thanks