SL/R129: AC Self Diagnostics - Cannot Run
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1995 MB SL500 (produced 07/95)
AC Self Diagnostics - Cannot Run
I am new to this site and first off want to say "Hello" to all R129 owners. What a fun vehicle to own and drive.
I have a 1995 SL500 (produced 07/95) with 79k miles and am having AC issues (compressor not engaging). It used to work (on and off, with a mind of its own) for awhile but now has quit altogether. I checked the Freon and it's fully charged. The pressure switches appear to work. (BTW: I put in a new compressor and drier just to see if that solved the problem, but it didn't). So I am at your site looking for assistance.
I have done exhaustive searches on this site and have come across some very helpful information.
I attempted to start with the AC Self Diagnostics routine, but my system does not seem to want to cooperate:
The instructions I have found for pre 9/95 production (129 Chassis to 8/95) are:
READING ACTUAL VALUES
1. IGNITION ON : Position 1
2. Press the REST button and within 1second press blower speed button 4.
3. The temperature window (upper left)will alternately display the test step number (ex. "02" In-car Temp)or"0P E" for Open Circuit or"Cl 0" for Closed Circuit.
4. Press "F" button to go tohigher test.
5. Press "C" button to go to alower test.
6. To end this testmode turn IGNITION OFF : Position 0 for longer then 5 seconds.
I perform Step 1.
Step 2: When I Press the REST button and within 1 second press blower speed 4 button (and hold them throughout the results outlined below happen):
1. A few strange symbols appear for about 1 second on my Temp Display.
2. I then hear a 'click' which sounds like a solenoid engaging and 22 deg C is displayed on the Temp Display.
3. About 1/2 second later a hear a double-click and the 22 deg C disappears from the Temp Display.
4. About 2-3 seconds later I hear another single-click and that is the last thing that happens.
Of Note: This exact same sequence happens if I just Press and Hold the REST button.
Can anyone tell me what I'm doing wrong?
Thx,
Jeff
I have a 1995 SL500 (produced 07/95) with 79k miles and am having AC issues (compressor not engaging). It used to work (on and off, with a mind of its own) for awhile but now has quit altogether. I checked the Freon and it's fully charged. The pressure switches appear to work. (BTW: I put in a new compressor and drier just to see if that solved the problem, but it didn't). So I am at your site looking for assistance.
I have done exhaustive searches on this site and have come across some very helpful information.
I attempted to start with the AC Self Diagnostics routine, but my system does not seem to want to cooperate:
The instructions I have found for pre 9/95 production (129 Chassis to 8/95) are:
READING ACTUAL VALUES
1. IGNITION ON : Position 1
2. Press the REST button and within 1second press blower speed button 4.
3. The temperature window (upper left)will alternately display the test step number (ex. "02" In-car Temp)or"0P E" for Open Circuit or"Cl 0" for Closed Circuit.
4. Press "F" button to go tohigher test.
5. Press "C" button to go to alower test.
6. To end this testmode turn IGNITION OFF : Position 0 for longer then 5 seconds.
I perform Step 1.
Step 2: When I Press the REST button and within 1 second press blower speed 4 button (and hold them throughout the results outlined below happen):
1. A few strange symbols appear for about 1 second on my Temp Display.
2. I then hear a 'click' which sounds like a solenoid engaging and 22 deg C is displayed on the Temp Display.
3. About 1/2 second later a hear a double-click and the 22 deg C disappears from the Temp Display.
4. About 2-3 seconds later I hear another single-click and that is the last thing that happens.
Of Note: This exact same sequence happens if I just Press and Hold the REST button.
Can anyone tell me what I'm doing wrong?
Thx,
Jeff
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1995 MB SL500 (produced 07/95)
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From: Atlanta, unfortunately
'09 S600, (2) R129 300SLs, '03 SL500, '03 SL55
The key should be in position 2 -- not 1.
For reference the diagnostic manual with the codes is here: http://manual.startekinfo.com/manual/JSP/cc/3_1/m11.jsp
For reference the diagnostic manual with the codes is here: http://manual.startekinfo.com/manual/JSP/cc/3_1/m11.jsp
Thread Starter
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Joined: Sep 2016
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1995 MB SL500 (produced 07/95)
OK...I'll give 'er a try this afternoon....thx bobterry99.
Thx for the reference.
WRT Test Step/Remedy:
What does Test Step/Remedy 23 => 1.0 refer to?
WRT Par C:
Readout of momentary sensor temperatures as well as potentiometer and feedback potentiometer voltages.
What values are the 'Nominal Values' compared to?
Thx for the reference.
WRT Test Step/Remedy:
What does Test Step/Remedy 23 => 1.0 refer to?
WRT Par C:
Readout of momentary sensor temperatures as well as potentiometer and feedback potentiometer voltages.
What values are the 'Nominal Values' compared to?
Thread Starter
Newbie
Joined: Sep 2016
Posts: 6
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1995 MB SL500 (produced 07/95)
Thx Plutoe.....that procedure works perfectly. Key just needs to be in Position 2.
What I can't find is the reference to the items listed under
Test Step/Remedy
e.g. 23=> 1.0
I have no idea what this is referring to.
Appreciate your help.
I found some intermittent codes and cleared them.
None have returned.
AC is still acting a bit peculiar, but will work most of the time.
What I can't find is the reference to the items listed under
Test Step/Remedy
e.g. 23=> 1.0
I have no idea what this is referring to.
Appreciate your help.
I found some intermittent codes and cleared them.
None have returned.
AC is still acting a bit peculiar, but will work most of the time.
Thread Starter
Newbie
Joined: Sep 2016
Posts: 6
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1995 MB SL500 (produced 07/95)
Plutoe,
So my A/C still seems to have a mind of its own.
I can start the car with the Temp on LO and Controls on Automatic.
The A/C may or may not work...normally NOT.
FYI...I'm in Huntsville, AL....temp is 95 degrees today.
If I then run the diagnostics:
<rest, 4> DTC's are tolerable values.
<F, recirc, rest> Permanent DTC: 01 END Intermittent DTC: 01 END
<recirc, rest, ^> Erasing DTCs: ---
Once I run these tests and start the car, the A/C works.
So again, I am stumped and can offer no reasonable explanation for the A/C behavior.
Any thoughts or guidance??
Oh BTW....just noticed a hydraulic leak in front of my driver's side tire after I lowered my soft top.
After investigation on this site, looks like www.tophydraulicsinc.com has all the answers I need. Guess I'll get to that sometime in the near future.
What a Great Site.
Also R129s are great cars...just the older ones (like my '95) need lots of TLC !
So my A/C still seems to have a mind of its own.
I can start the car with the Temp on LO and Controls on Automatic.
The A/C may or may not work...normally NOT.
FYI...I'm in Huntsville, AL....temp is 95 degrees today.
If I then run the diagnostics:
<rest, 4> DTC's are tolerable values.
<F, recirc, rest> Permanent DTC: 01 END Intermittent DTC: 01 END
<recirc, rest, ^> Erasing DTCs: ---
Once I run these tests and start the car, the A/C works.
So again, I am stumped and can offer no reasonable explanation for the A/C behavior.
Any thoughts or guidance??
Oh BTW....just noticed a hydraulic leak in front of my driver's side tire after I lowered my soft top.
After investigation on this site, looks like www.tophydraulicsinc.com has all the answers I need. Guess I'll get to that sometime in the near future.
What a Great Site.
Also R129s are great cars...just the older ones (like my '95) need lots of TLC !
