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(B5) Ac request question

Posted: Thu Jun 05, 2008 3:37 pm
by Richie2
Hi I want to use he AC button to activate FTL and also to use it as the input for the gpo and secondary maps. Choosing the AC as input for both brings a message that AC request is allready in use. Would that be a problem or can I use AC request as two inputs? And the most important question, is that I removed the AC completely, and I want to know if I have to ground anything in order for the AC request to work? And also If so, can someone tutor me on what exactly to do, I don´t know which plug is what anymore, I know one worked the fan, another the compressor but I get lost on what excatly I have to look at Thanks

Re: (B5) Ac request question

Posted: Thu Jun 05, 2008 8:41 pm
by JaredKaragen
Richie2 wrote:Hi I want to use he AC button to activate FTL and also to use it as the input for the gpo and secondary maps. Choosing the AC as input for both brings a message that AC request is allready in use. Would that be a problem or can I use AC request as two inputs? And the most important question, is that I removed the AC completely, and I want to know if I have to ground anything in order for the AC request to work? And also If so, can someone tutor me on what exactly to do, I don´t know which plug is what anymore, I know one worked the fan, another the compressor but I get lost on what excatly I have to look at Thanks
There is one pin under the hood for the AC system pressure sensor; you need to jumper that to ground, or if the AC subharness is removed; you can jumper that pin to the black/white wire on the connector the subharness plugs into. Now; I will try to get a pic up tonight for exactly what wire to use; But there are 2 notes to be aware of: The AC switch will not work for an input unless the fan switch is on setting 1 or higher; meaning, no AC light, it's not working right. Secnd; it's just letting you know that the AC switch is already activating some other feature... as long as the feature it's using is an on/off feature like FTL is, there is no issue.... if u think enough you will understand. Now you can bypass the need for turning the fan on to use the AC request by taking the climate controls out, and jumpering the +12V from the fan switch to the AC request via a diode (1N4001 will probably be fine). The diode is to make sure the + voltage being used for the AC button is not back-feeding into the rest of the circuit but if my memory serves me; it might be on a seperate portion of the fan switch. Ill try to get pics; they say alot more than text!

Posted: Fri Jun 06, 2008 7:51 am
by Richie2
thanks for the info. Is there a way that I can ground switch and then pin the ECU. What exactly doe the ECU want to see when AC request? Does it want to see ground or 12+, and in what pin? pics would be great, thanks :)

Posted: Fri Jun 06, 2008 8:14 am
by calvin
ground there is another thread with this info. use search