Klima > Ice Cube - Not Working
 

Though I am going to check my connections again (3rd time) the replacement of the Klima with an Ice Cube is not working on my '87 300TD. A fuse jumper wire from #5 to #7 makes the compressor engage yet when I put my Klima replacement in, the compressor would not engage. Any thoughts on this one would be greatly appreciated.

Following the MB Service Manual ACC for Model 124 I ran the sequence of tests "Checking compressor cutoff if the electromagnetic coupling of the compressor is not switched on." Each test returned nominal values. That brought me to "Renew control unit (N6 - Klima)." That being said, again I put my Ice Cube for Klima replacement in. No compressor engagement. Remember, in the testing sequence terminals 5 & 7 are jumped and the compressor did engage.

Ideas on what to do PLEASE.

Still moving on with this project I found -0- volts at terminal #4 of the Klima socket with the engine at idle and appropriate switches set. According to the SB link, voltage should be battery until full throttle. If I am heading in the correct direction, this may indicate that the full-throttle micro-switch is closed all of the time. If it is in fact bad, would this explain why the Ice Cube relay replacement for the Klima isn't working for me? Is there anything short of replacing the micro-switch I can do?

Can you post the wiring layout you used to build your Klima replacement? Which terminal on the car is connected to which terminal on the ice-cube?

I doubt the full throttle micro-switch is the problem with your ice-cube bypass. It would take multiple ice-cube relays to include the full throttle shutoff logic into the Klima replacement. There's a reason MB used electronics...

- JimY

Tha A/c panel must send a GROUND signal to the Klima relay for the compressor to engage. That signal comes in at pin 10 of the klima relay.

Also the tachometer must work & the RPM signal must come to the klima relay as well.

There is also an overheating switch on the engine that can stop the compressor from comming on. TRY disconnecting that switch to see if the switch is shorted.

Also on the accelerator linkage there is a limit switch that cuts off the compressor durning acceleration, try disconnecting that switch as well.

JCYUHN
Okay . . . the wiring layout for my Ice Cube (replacement for Klima) is #1 > #85, #10 > #86, #5 > #30 and #7 > #87.


M.B.DOC
The ground coming in at #10 is present i.e. battery voltage with #10 (-) & #5 (+) reads battery voltage.

Tach is working properly as is speed sensor test.

The emergency cutout temperature switch results in < 1 volt when tested at #5 (+) and #12 (-).

I am uncertain if you mean the micro-switch for full throttle as to your reference to the throttle linkage. If so, where I should be getting battery voltage at #4 of the Klima socket I get zero. Unplugging the connector at the bottom of the micro-switch does not change it one way or the other.

I am wondering if the lack of battery voltage at #4 is indicating that the micro-switch portion of the circuit is the problem. If I understand it correctly, when it operates correctly there would be battery voltage until the micro-switch passes full-throttle and cuts the compressor for extra hp. This is where I am stuck . . .

Going to talk my way through this one . . . I believe I was wrong in thinking the micro-switch is the culprit. As I view the schematic it appears the micro-switch grounds what is supposed to be the battery voltage at #4 in the Klima socket. If I am reading the schematic correctly that would mean since there is no voltage at #4 I'm heading in the absolute wrong direction. I believe I need to find where the source of voltage to #4 is and find why it is not present at the socket. On the other hand, if the voltage only gets to #4 from one of the internal sources of the Klima, with the Klima out I wouldn't find any present at #4. I doubt myself on that last statement since the SB explanation link refers to either the EGR controller or the idle controller ISC as a source of converted pulsed DC signal that drops out when the micro-switch engages at full-throttle. As I read that portion of the explanation I am probably not going to find battery voltage at #4 . . . ??? Too late to be this lost.

Try this ...
Unplug both temp cut out sw and full throttle sw circuits [ 4 and 12]
and then ground #10.

Glad to try . . . before doing so, you are saying to unplug the switches at their source and ground #10 at the Klima socket? I am trying to understand another way of accomplishing it. The only other way I can think of is to remove the socket and attempt to remove the female ends from the socket block.

#10 I believe is the compressor pressure switch
#4 is the micro-switch cutout
#12 is the temperature switch with one side (b) emergency cutout

Sound correct?

Arthur
Tried unpluging connectors at S25/5 (#12 at Klima socket) & S27/1 (4 at Klima) then grounded S31 (#10 at Klima) with no compressor engagement. All of these were done with the Klima plugged in and the connections interrupted at the individual switches.

OK
That test was to test the relay circuit and acc panel to seek ground..
Unplugging both the temp and throttle sw eliminates them [ they ground to stop comp]
Grounding 10 at relay eliminates the comp pressure circuit/panel
When you jumper 5 to 7 , you are bypassing the relay circuit..[simply jumping the load contacks of the relay]
So, you are down to relay /modual input fault

You have the schematic there ?
I am not sure if I am on the right one ....

Arthur
Just got Adelphia Powerlink back . . . read your message and was getting itchy since I couldn't let you know I have the schematic.
Steve

Me too
I was trying to trade some stocks and lost mine [ powerlink] too
Anyway, which schematic should I be looking at ??

Just so you don't have to make assumptions, my car is an '87 300TD so that is Model 124.193 with the 603.960 engine. My schematic is from the MB Service Manual - Automatic Climate Control Model 124. Though I haven't checked, I believe it is the same on the CD volume.

I went through the testing procedures for all of the Klima connections listed in the manual. Everything passed which led to the Klima (according to the manual). Since I wired the Ice-Cube according to this forum I thought it would replace the Klima and work okay. Not so.

Hope this helps show where I have been so far. I am really stumped at this point.

Thanks a bunch for taking the time to look this over for me.

Steve

I see no s25/5 , but s25/11 feed from 12.

There is an idle rpm ,min 600rpm, with a 10 sec delay input at pin2.
Do you show that?????????/