Guess what I'm up to... :) - Page 2 - PeachParts Mercedes-Benz Forum

Stretch · #16 05-29-2011, 04:43 AM

Quote:

Originally Posted by locry

The wires are NO WHERE as intimidating as a w140's... this is easily 1/8 the amount of wires on a w140!

Well compared with a w123 that's a lot of wires!

(I can post proof if you want)

locry · #17 05-29-2011, 06:16 AM

Haha! I believe you I believe you!
Every model change the wires grow exponentially.

sjh · #18 05-29-2011, 08:33 PM

Quote:

Originally Posted by locry

@sjh,
The opening I'm referring to is inside the car, That's the only opening that I can see where fresh air can be drawn in. It's not clear in the pics I know

.
I know of the fresh air inlet, that half of the airbox sits outside the firewall...

OK. I'm thinking you are referring to either the green or red arrow I've drawn.

Either way it does not look like I can easily access that from under the dash or through the glove box.

locry · #19 05-30-2011, 01:36 AM

it's the opening the red arrow is pointing to... it actually goes all the way across to the other end. Nope, you absolutely cannot access it through the glovebox or anywhere for that matter. Removal of the dash is your only option, and even then the vacuum pods will get in the way probably. I've since removed all of those.

btw, i'm getting an underdash unit later today, i'll know later if it'll fit without much effort. I'm thinking it will.

(hoping actually)

locry · #20 05-30-2011, 10:20 AM

go back to stock?...or.....

lots of space without the original airbox!!! it even cleared the tunnel carpeting!

locry · #21 08-08-2011, 02:44 AM

I'm finally done with the entire install... I just recently finished re-wiring the pushbutton control unit in place of the rotary switch that came with the evap/bower kit.
I wired 6 relays to the CCU so I can now control the ac through the buttons.

the 3 fan speed buttons now function as 1,2,3 fan speeds. 3 more buttons are used for off, econ, normal modes. It involved hacking the CCU pcb.
Cleaned everything inside the CCU now the markings are brandnew bright.

dagObx · #22 08-08-2011, 02:20 PM

Photos, please!!!

panZZer · #23 08-08-2011, 04:31 PM

Quote:

Originally Posted by locry

hehe... will try to itemize the procedure.

This is the 2nd time I've done this... I still do not like it! haha. but it is doable... took me 4 hrs.
I'm considering retro fitting a much simpler underdash unit... for easier future maintenance.
Any opinions?

Vintage air in San Antonio is the top aftermarket retrofit outfit

locry · #24 08-09-2011, 12:34 AM

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..

sixto · #25 08-09-2011, 12:58 AM

You realize you'll have to redo all that when you get your hands on a Euro AC control panel, right?

http://cgi.ebay.com/ebaymotors/310271592135

Sixto
87 300D

locry · #26 08-09-2011, 01:11 AM

hahaha, I could've gotten a cheap set but I opted to stay "stock"... hahaha, after hacking the hell out of the car I have the nerve to say "stock"...

ashedd · #27 08-09-2011, 03:12 AM

Quote:

Originally Posted by locry

I wasn't sure how much current the compressor clutch draws

(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)

Since you have it working it's easy. Just turn it all on and measure the current draw at the compressor with a multi-meter. If I had to wager a guess... I would say 6-8 amps.

locry · #28 08-09-2011, 03:15 AM

is 6-8 amps safe for switches? is it safe for me to supply the clutch with the 'positive' wire that's also supplying my 2 MAIN relays?

ashedd · #29 08-09-2011, 12:54 PM

I am having a hard time "following" your circuit. I need to see a schematic to totally understand what your doing. I have the basic concept understood. But 6-8 amps would be too much current to run through the PBU switches. You would surely need another relay for the clutch on the compressor.

locry · #30 08-10-2011, 02:56 AM

I indeed have a separate relay for the compressor clutch installed right now.

I don't know the first thing about writng a 'proper' schematic.