Thread: Manual fan override using A/C button question

The A/C button has 3 wire coming out of it, Green/White stripe, LightGreen/Red Stripe and LightGreen/Black Stripe. My question is which one of this is the ground? My guess is the one with black stripe but want to make sure before I end up doing something I shouldn't and burn the ECU. Can someone help or confirm this? Thanks

I have seen threads where people have done this, none have good info in them though. I am a wiring novice and I would like to know as well.

for what car is it??
b13 harness for sr models says:
Light Green/Black - only goes to thermal control amp
Light Green/Red - activation switch via the fan switch (Power)
Orange - thermal control amp and AC relay activator

so technically there is no "ground" per say but light green/black would be your best bet to tap. don't completely cut them. but you might be increasing the load on the wire to power a fan. i suggest tapping it to a relay to activate power to the fan.

however, the power source is light green/red. it'll only transfer power when the blower motor is on (1-6).

don't worry about burning the ECU. according to the FSM, the AC switch circuit doesn't connect to any ECU components.

good luck!

It wouldn't work without the fan off?

nope. if you think about it. when you push the AC button, the indicator light won't turn on until the blower is on.

oh yeah, if you don't have AC anymore. the AC switch is a single input, dual output switch. So light green/red is your 12v input. then light green/black and orange will be your output/ground.

How would I configure grounding pin 9 on the ecu(controls the fans, turns them on when grounded) to ground when I turn this button on. My 3 wires are green/red, green/black, and green/white on my a/c switch.

Cmon guys I know someone can help

Are you wanting the rad fans to turn on, or are you trying to force the a/c to stay on longer? If you want to force the rad fans on you're better off jumping the radiator fan relay.

Either way you should goto the local eletronics store and pickup a cheap multi meter that can test continuity and check the switch to see which terminals are bridged when the button is pressed.

All I want to do is be able to turn my fans on manually using the A/c button as a switch. I'm just not quite sure how to do it. If you ground pin 9 on the ecu harness the fans come on. So basically I just want to know how I can hook up my a/c button to ground the pin on the ecu, and light up when the fans are on. There are 3 wires, green/white, green/red, and green/black. Can I just run 12v acc to the green/red, pin 9 to green/black, and ground green/white?

The car does not have a/c anymore so the button only needs to function as a switch.

There is a specific wire coming from the ecu that when grounded turns on the fans. All you need to do is wire into that wire and have the switch ground that wire. The wires will see no load as they are only signal. Works great.

Dudeman