help please - radiator fan

[krock]

hey i have an fxgt ae101. The air con has been removed and the radiator fan is staying on full time.
i have done searches on this and have identified there are two green wires on an air con pressure switch which need to be bridged.

- providing that the air con switch in the ae101 is a plug with 4 wires going in to the back of it, and is mounted on an aluminum air con pipe in close proximity to the ignitor, i have done the required connection and fan is still going full time.

- i have also tried earthing out the fan switch/sensor unit which stops the fan going.

- at one point i moved some wires in the engine bay, possibly an earthing wire (on the drivers side of the engine bay) which stopped the fan going. i figured it was a bad earth and that it was fixed, but then the fan later went back to going full time.

so can anyone point me in the right direction with this?

does anybody have a spare radiator fan switch(silver-top 4age obviously) that i could try out so i don't have to waste $60 - $70 odd on a new one if this isn't the problem?(did this on another car recently)

would really appreciate any help on this,

cheers kirk

[sergei]

Fan switch is fairly simple device, you could determine if it is faulty or not by just grounding the wire that comes off it and/or by measuring continuity between the thermostat cover (ground) and the pin on the switch on cold.

If you ground the wire (on the connector that plugs into the switch) it should stop the fan.
If it does not stop the fan, it means that you pressure switch bypass is not right, or something else is faulty.
The relay uses "On by default" contacts to drive the fan. When relay is OFF the fan will be ON. When you are grounding the wire going to the switch you are grounding the relay and turning it ON (thus turning the fan OFF).
The fan relay is located in fuse box (and will be on the "map" on the top cover) you could check the connectivity between the relay pin that is supposed to ground and the thermoswitch end.

[sergei]

also the diagram for the whole system is as such:

Code: Select all


--------+-------- +12V
       _|_     
      |   |     +---
relay |   |===. L  => to fan circuit
      '-+-'     +---
        |       
         \ thermoswitch
        +
        |
         \ pressure switch (A/C)
        +
        |
        |
      -----
       ---      <= ground
        -

     

Where "L" represents closed switch and "\" represents open switch.

[krock]

yes, when i grounded the switch, the fan did turn off. does this confirm that the switch is faulty?

[sergei]

yes, when i grounded the switch, the fan did turn off. does this confirm that the switch is faulty?

pretty much. Unless you have completely insulated thermostat housing where switch is screed into, or used thread tape on the switch.

[krock]

ok, sweet thanks for that, i'll try one out and let you know if it works. cheers

[krock]

SORTED.

Replaced thermo fan switch and in conjunction with the two green wires connected, problem is solved.

cheers