Re: [MBZ] 1987 300TDT (W124) Climate Control Problems
Steve, Sounds like vacuum pods to me. And it sounds, from memory, like the system may be operating normally with the exception of the center pod. As for the need for the breakout box, I was able to work around it with the test instructions and an inexpensive VOM. For both 123 and 124 models, the instructions include wire harness test points, test mode, and pass/fail parameters. If you need more of a hint, I'll hunt around for my markup, but you should be able to discern which component, associated power supply, ground, or signal wire is being tested in each step, to fault isolate without the breakout box. Mike Boerner 87 300SDL 125kmi 87 300D 130kmi
Re: [MBZ] 1987 300TDT (W124) Climate Control Problems
Based on on the response that I got to the post below, it seems as though the cause of the ACC problems may be the control unit. I believe the control unit is original and has never been changed. Any additional thoughts or ideas? After looking around, it seems as though a rebuilt control unit is available. The ACC control units are rebuilt by Programa. Does anyone have any experince with the Programa rebuilt climate control units? I seem to recall readig some negative posts about Programa rebuilt climate control units for the W123. Thanks, -Steve From: [EMAIL PROTECTED] Date: 2005/10/28 Fri AM 08:31:38 PDT To: [EMAIL PROTECTED] Subject: 1987 300TDT (W124) Climate Control Problems The climate control system in my 1987 300TDT seems to be operating improperly since I cannot get heated air out of the footwell flaps. When the system goes into heat mode (temp dial between 22 and 18, EC button pressed, fan on auto, outside air at 55 degrees F)), the air seems to only come out of the defrost vents and the lateral vents on the ends of the dash. The climate control (ACC) seems to switch between full heat out the defroster and lateral vents and cool air from the center and lateral vents to try and keep the interior temp at the right temp. The ACC doesn't seem want to use a medium fan setting with only warm air for some reason. Placing the temperature dial at max with the solid down arrow and outline up arrow button pressed (with or without EC marking), and the fan button at auto seems to make no difference, the air still comes out of the defrost and lateral vents. Additional info: The fan operates properly at min, max, and auto when pressing each of the buttons. Occasionally when I turn the climate control on, I can hear a faint clicking sound from behind the glove box area and nothing happens initially until after 5 or 10 seconds. There are also occasions when I press the off button, and the climate control system runs for about 15 seconds, and then it shuts off. The only time I am able to get air out of the footwell vents is when I press the button with the solid up and down arrows. I have tested all of the vacuum pods and they all hold 15 in Hg of vaccum except the center vent pod. I have also swapped the hoses for center vent pod and the air diverter flap pod to get air around the bad center vent pod temporarily. The air sample fan is working properly since it seems to hold a small 1 cm square of paper at it's intake point on the dome light. I have the MBZ Climate Control Service Manual, and I have run the functional tests and based on the results the manual says to run the electrical component test which seems to require a special test instrument/breakout box that cost 400 dollars plus. Does anyone have any ideas on what component might be bad? At this point it looks like it might be the control unit, but I need to run more tests. Any thoughts and ideas are welcome. Thanks in advance. -Steve
Re: [MBZ] 1987 300TDT (W124) Climate Control Problems
[EMAIL PROTECTED] wrote: Based on on the response that I got to the post below, it seems as though the cause of the ACC problems may be the control unit. I believe the control unit is original and has never been changed. Any additional thoughts or ideas? After looking around, it seems as though a rebuilt control unit is available. The ACC control units are rebuilt by Programa. Does anyone have any experince with the Programa rebuilt climate control units? I seem to recall readig some negative posts about Programa rebuilt climate control units for the W123. Thanks, -Steve You REALLY do need to run the diagnostics listed in the manual before condemning the control unit. With many failures the system defaults to DEFROST mode. Could also be the vacuum manifold or some of the vacuum actuators (very likely to fail in an '86-'87 126/124 model car) that are not properly functioning. Read the manual to determine HOW the system works and perform the diagnostics to find out which parts are not operating as they were intended to operate. Throwing parts at the climate control system of a Mercedes is usually the most expensive way to solve the problem - and it actually may NOT solve the problem. The system is VERY complex and it does NOT operate in a manner that is intuitive to most people (especially people that have a background working on American or Japanese cars). Marshall -- Marshall Booth Ph.D. Ass't Prof. (ret.) Univ of Pittsburgh School of Medicine Department of Pharmacology 1300 BST Pittsburgh PA 15261 USA [EMAIL PROTECTED]
Re: [MBZ] 1987 300TDT (W124) Climate Control Problems
Steve This is a site for a tool loan program that was set up to address just the situation you have. It seems to work real well but you'll have to ask if someone owns the test equipment you need. http://www.mercedesshop.com/shopforum/showthread.php3?t=126728 Harry Watkins Newton, MS 86 SDL Silver 85 300D Euro 86 SDL Gold 81 240D manual trans - Original Message - From: [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Thursday, November 03, 2005 2:23 PM Subject: Re: [MBZ] 1987 300TDT (W124) Climate Control Problems Marshall, Thank you taking the time to respond to my post. I did actually include in my two previous posts that I have actually already gone through the diagnostics in the MBZ climate control service manual up to the point where I need a $400 dollar test fixture to check the electrical components of the ACC. .. Ideally, I would like to run the electrical component test using the nice breakout box/test fixture that Mercedes shows in the ACC manual, but I cannot see spending $400 plus dollars for a very specialized tool. If someone has test fixture they would be willing to loan out, I would be very grateful. -Steve
Re: [MBZ] 1987 300TDT (W124) Climate Control Problems
Mine does this too, you have to buy the whole climate control unit. On 10/28/05, [EMAIL PROTECTED] [EMAIL PROTECTED] wrote: The climate control system in my 1987 300TDT seems to be operating improperly since I cannot get heated air out of the footwell flaps. When the system goes into heat mode (temp dial between 22 and 18, EC button pressed, fan on auto, outside air at 55 degrees F)), the air seems to only come out of the defrost vents and the lateral vents on the ends of the dash. The climate control (ACC) seems to switch between full heat out the defroster and lateral vents and cool air from the center and lateral vents to try and keep the interior temp at the right temp. The ACC doesn't seem want to use a medium fan setting with only warm air for some reason. Placing the temperature dial at max with the solid down arrow and outline up arrow button pressed (with or without EC marking), and the fan button at auto seems to make no difference, the air still comes out of the defrost and lateral vents. Additional info: The fan operates properly at min, max, and auto when pressing each of the buttons. Occasionally when I turn the climate control on, I can hear a faint clicking sound from behind the glove box area and nothing happens initially until after 5 or 10 seconds. There are also occasions when I press the off button, and the climate control system runs for about 15 seconds, and then it shuts off. The only time I am able to get air out of the footwell vents is when I press the button with the solid up and down arrows. I have tested all of the vacuum pods and they all hold 15 in Hg of vaccum except the center vent pod. I have also swapped the hoses for center vent pod and the air diverter flap pod to get air around the bad center vent pod temporarily. The air sample fan is working properly since it seems to hold a small 1 cm square of paper at it's intake point on the dome light. I have the MBZ Climate Control Service Manual, and I have run the functional tests and based on the results the manual says to run the electrical component test which seems to require a special test instrument/breakout box that cost 400 dollars plus. Does anyone have any ideas on what component might be bad? At this point it looks like it might be the control unit, but I need to run more tests. Any thoughts and ideas are welcome. Thanks in advance. -Steve ___ For new parts see official list sponsor: http://www.buymbparts.com/ For used parts email [EMAIL PROTECTED] To Unsubscribe or change delivery options go to: http://striplin.net/mailman/listinfo/mercedes_striplin.net -- Gabriel Soto Southern California 1987 300D 230K=-
