prestige ss9600

i have found the wire on the back of the climate control that when you press the defrost button it rises from 3-12 volts for 1sec. however when i apply 12 volts to the same wire via a relay the defrost does not kick on. I have also identified the wires that when you apply ground the fan goes to high and the air comes through the AC vents.

does this make any sense:)

Yes you apply a NEG (-) pulse.

yest the neg pulse turns the fan on high but the the dampers for the defrost do not redirect to the windshield. I just get heat on the feet.  

i have found the wire on the back of the climate control that when you press the defrost button it rises from 3-12 volts for 1sec but i cannot seem to activae it

Why the repeated running around in circles? I've ALREADY told you where the wire is, what colour and how to test activate it.

my bad. i thought the wire you were referring to was for the rear defrost and not the front. Ill give it a shot

thanks

White wire, pulsed did not activate the front defrost.

thanks

I'm sorry I thought it was the rear you were after that's the norm. What happens if you set up the defrost then turn off the ignition? Does it come back on when you turn the ignition on again? That's how I do it.

that would work.  i am just looking for a little more automation. i have probed every wire on the back of the climate control and can turn the fan on high and move the damper to the AC position only. just cant get the damper to the defrost position.

I am so close.

I can acutally see the damper actuator just cant reach it to apply ground pluse.

Be careful, the actual actuator won't have a ground pulse it will have two "motor" wires what you're looking for is either written code in the BECU via DATA so forget or a relay output to that actuator.

yea, interfacing climate controls, especially in high end cars can be tricky or impossible without an interface device. chances are that the climate control panel goes straight to a computer controller which translates into different actions. continue at your own risk! you say that the wire goes from 3v to 12v when you push the defrost button. perhaps that wire needs to cut from the controller when you apply 12v. the fact that you are seeing a voltage shift probably means that the controls could be resistance based. does that wire do anything else when you push any other buttons? or is is just related to the defroster? if you want to get a little more extreme you can open the control panel and see how hard it would be to solder directly onto both sides of the defrost button then connect those two wires through a relay which would directly simulate the button press.