Will upload pics... but here's a brief description of the CCU hack:
-Disassemble the CCU unit
-cut/disconnect the ribbon cables of both the fan speed switches and the illumination unit (you'll know it when you see it)
-identify the PCB paths of the 3 buttons that you wish to utilize (the horizontal row of buttons)
-scratch them out using the tip of a small screwdriver, make sure there's no continuity when you're done
-identify which "prongs" on the individual switches closes the circuit for each switch (in my case its the rear most prongs and the middle prongs) use a multitester to be sure
----------------------------
I decided on using 3 of the horizontal buttons for turning on the AC normally, fans only and off.
I also decided on using the 3 fan speed buttons (vertical ones) as 1,2,3 fan speeds
I used a total of 6 Relays.
3 relays go to each fan speed switch
2 relays go to the "normal" on button
1 relay goes to the "econ" button
You will basically make 2 relay groups.
The "MAIN" relays, connected to the "main" buttons and
the "FAN" relays, connected to the 3 fan speed buttons
The main relays have a common ground, so I bundled their ground 'trigger' wires together.
They also have the same 'supply' trigger wires so bundle I them together as well...
The ROLE of 2 of the MAIN relays, when TRIGGERED just supplies a POSITIVE current to the "FAN" relays' 'triger' supply lines... (x3)
(NOTE: I used low current negative and positive connections to trigger the relays)
The "FAN" relays just closes the loop for the high current lines which are connected to the blower resistor unit.
BTW... to make it simpler, I just bundled ALL the relays' 'trigger' grounds together.
Why a 3rd relay for the MAIN group? I wasn't sure how much current the compressor clutch draws so I just isolated its circuit by using its own relay... attach that relay to the "normal" button... but use the high current line instead of the low current trigger lines to close the compressor clutch loop.
In summary,
when the OFF button is depressed, none of the relays are energized
when the ECON button is depressed, it energizes its RELAY which in turn supplies and energizes another relay (whichever fan speed button is depressed), which in turn closes a high current loop powering the blower.
when the NORMAL button is depressed, it energizes 2 RELAYS, one similar in function to the one above...AND the other, simultaneously, closes the loop for the compressor clutch.
(I could do away with the compressor clutch relay IF the clutch didn't require much current... but that I have no idea how to compute)
I'm not an auto electrician, so I do not know if used the correct terms, but I made sure I used the correct wires/connections so as to isolate high and low current requirements... thus the use or overuse of RELAYS.
i know, pictures!!!
btw...
the BLOWER/EVAP unit I bought came with e ROTARY switch that has 5 wires coming OFF it, 3 are for the 3 fan speeds, 1 main supply line and 1 clutch trigger wire(connected to a rotary thermostat). This is where I ended up connecting wires to.
How do I control the temp then? Since I live in a tropical country, I opted to just set the temp on cool all the time, and just HID the thermostat behind the CCU....
Almost forgot... just solder 2 long wires for the light bulb unit and splice that to something which is triggered by ILLUMINATION..