I'd like to start up a thread where we really figure out how to retrofit the automatic climate control system. For a lot of people, the cost / benefit ratio of this job will be well above their comfort zone. Expect to have to take the dash out and disassemble your AC system.
With that being said, I've spent a lot of time looking at the wiring diagrams for both the manual and automatic climate systems - From just the electronic components alone, These are the components listed for the Auto climate system:
Blower Motor Relay,
Blower Motor,
Blower Motor Resistor,
Ambient Temperature Sensor,
Evaporation Thermoswitch,
Air Mix Actuator,
Sunload Sensor,
In Vehicle Temperature Sensor,
fresh/Recirc Actuator,
Mode Actuator,
Auto A/C Control Panel.
Looking at part numbers, the Blower Motor Relay, Blower Motor, Fresh/Recirc actuator, and the Mode Actuator are the same units as what is already in the manual car - so, that means the new/additional components come down to:
Blower Motor Resistor,
Ambient Temperature Sensor,
Evaporation Thermoswitch,
Air Mix Actuator,
SunLoad Sensor,
In Vehicle Temperature Sensor.
A/C Control Panel.
Simplest way to get the wiring is to source an instrument and body harness from an Auto Climate equipped vehicle and strip the harness to it's just the climate subsystem.
To hook the wiring into an A/C car, we look at the wiring diagram and figure out how to get the AC panel all the required inputs.
Inputs needed from Manual harness
Auto A/C Control Module - Existing harness location & pin
A8 / FB-19 - i17 pin 8
A13 / FB-22 - i17 pin 14
B1 / FB-33 - Radio, i26 pin 6
B2 / FB-28 - Front Accessory, i24 pin 2
B3 / B88 Evaporation Thermoswitch Pin 3
B4 / B88 Evaporation Thermoswitch Pin 1
B5 - VSS
B10 - i17 pin 17
B14 - i17 pin 19
B15 - Vehicle Engine Temperature - B21, pin 10
B20 - i17 pin 18
Since the blower motor resistor is different, one possible way to branch into that circuit is to use the auto AC harness from the blower motor pin 2 and on
Some outstanding questions:
1) What EXACTLY does the air mix actuator do? Control Temperature? Are all the necessary fixings on the manual box? Basically, can you just install the servo and call it good or do you need to swap the whole assembly?
2) Where EXACTLY does the aspirator tube from the Automatic Climate control unit connect to? Does that socket exist on the manual box? (you will need this for accurate temperature readings)
3) The thermistors are different. The manual has a 3 wire thermistor, the automatic is a 2 wire - fine, but what exactly are the specs on these? Can the 3 wire be hooked up in such a way that the signal is the same as what the 2 wire sends to the control unit? If not, again, the box will have to be dismantled to gain access to the condenser.
I've not yet seen somebody successfully do this swap, let's figure it out - well, I want to figure it out anyway, and see exactly what needs to be done. That way, in the future, if somebody wants to go down this path, we'll somewhat know what needs to be done.
Also - for the sake of my discussion, let's stick with retrofitting the system into a H4 with the compressor which does NOT have the compressor speed pulse sensor, that's a circuit which is specific to the H6 ECU which we will not be using.
I'll add to this thread as I go along.
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