Hi All,

i have a 2005 Mustang GT, Supercharged with a procharger D1SC, running around 410 bhp..

I’m having some major problems with my heating system. After investigating further i came to find that the fans are working when they wanna work..

On the 2005 the fans have 2 settings, High speed and low speed.. When i drive normal the fans are ok (on low speed) but when i take the car on a joy ride the fans stop and the car overheats immediately.. After data logging the car several times i saw the fans from the PCM shows everything is fine when in low speed mode, but then when it changes to high speed the fans do not come on and of course the low speed fans have turned off to allow the high speed fans to take over..

Sometimes the datalogs even show the high speed fans are working but when i stop the car and check the fans are not on, causing the car to overheat in know time..

Has anyone and ideas or suggestions? i have checked the fuses and relays = Fine, i have changed the thermostat already.. The tune is correct..

Does anyone know where i should be looking to resolve this problem?

Thanks in advance for any help u can offer.

Cheers.

Mark

 

You can adjust when the fans come on in your tune. Try having them turn on at a lower temp....

 

done this, they still turn off.. the high speed never work.. the low speed turn off when i screw the car, even though its programmed to stay on till 210.. and come on at 185

 

Idont recall how the fans are set up, but if the high speed fans dont work at all, is it a separate sensor, are the high speed fans getting power(loose or disconnected wire), fan motor working properly. I'm at work now, but can checkmy forddvd when i get home for some poss causes...

 

thanks, that would be great if u can.. im at the last straw with they car now and just wanna burn it. if u could let me know that would be great. thanks.

 

Hey Trigger........Have some pdf's for you but am unable to post them. PM me you email and i'll send them to you.....

 

you might try to connect the fan directly to the battery to makeit run constantlyat full speed, then drive the same way you do when the car overheats, if it doesnt overheat then you know there is something wrong with the fan, or the sensors, or the signal that makes them turn on or off.

 

The PCM is commanding the high speed fan on, thats what you are seeing in datalogger. So, the PCM wants the fan on but they don't come on. This means the PCM is providing a ground for the control side of the high speed fan relay. This relay is located in the junction box behind the passenger headlight. You could have a bad high speed fan relay. Basically the system works by providing a resistive (low fan) and non resistive power (high fan) to the motor. Your fan is likely good, I think you have a bad relay or a wiring issue between the fan and the box or between the box and the PCM that is not allowing it to work. You should remove the high speed fan relay. Put a paper clip in the terminals labeled 30 and 87. This isshould make the fan work if the relay is bad orif the control circuit to the PCM is open. Begin here. It is by far the most likely source of your issue. Good luck,keep us informed.