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Old 03-17-2017, 05:47 AM   #1
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HVAC wiring diagram to convert to switches

Further down the slippery slope I'm trying to remove my radio and HVAC controls in place of a panel and need to add a switch to turn on the heat/defrost. I've searched for a wiring diagram of the HVAC control to help me but haven't had any luck. Does anyone have a diagram, or better yet know how to rig this up? As of now the car also still has AC, I've stripped the car of just about everything but just can't convince myself to drop the AC yet.


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Old 03-17-2017, 06:05 AM   #2
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Depending upon the year of the car, AC and heat function are handled over the CAN Bus via a control module.
Anything really new is invented only in one’s youth. Later, one becomes more experienced, more famous – and more stupid.” - Albert Einstein
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Old 03-17-2017, 06:20 AM   #3
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doubt you can do it if you want to keep ac - the hvac controller has a 'brain' that considers outside temperature, engine speed, cabin temp, and a bunch of other stuff when running the ac - note that the ac compressor has an electric clutch that gets turned on an off.

it gets easier if you don't want ac - ultimately you are just turning a fan on and off. there are race systems you can buy that let you delete the entire oem hvac system. if you are looking to lose weight but keep a stock appearance, note that in north america all cars came with ac except the gt3 - you can get a gt3 heater matrix and controller that is a lot lighter and uses dials instead of a computer. rare as hens teeth, however, BUT, note that ac wasn't standard in europe, so you can find the non-ac systems on euro ebay but don't get anything from uk as the matrix is reversed.
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Old 03-17-2017, 07:37 AM   #4
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What year is your car? I can send you the wiring diagram if you have a 97-99. PM me.

Otherwise, I'd suggest buying a Bentley manual; the wiring diagrams for all years are in the manual.

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