Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help

Go Back   PeachParts Mercedes ShopForum > Technical Information and Support > Tech Help

LinkBack Thread Tools Display Modes
Old 05-15-2001, 11:21 PM
Posts: n/a
On my 89 260 E 124 the ac clutch does not kick in,,,,any ideas on what to check , what is most likely to have gone on strike?

Thanks A bunch
Sweating in California.
Reply With Quote
Old 05-16-2001, 01:19 AM
Registered User
Join Date: Mar 2000
Posts: 532
Several faults could result in an inoperative compressor clutch. Assuming intact wiring and fuses, the mostly likely cause is an inadequate refrigerant charge: the clutch (and thus compressor) is rendered inoperative if system refrigerant pressure falls below a set level. The Nippondenso compressor used with this vehicle has no oil sump and depends on the refrigerant to carry its oil.

If gauges are unavailable, a quick check for adequate freon charge can be accomplished by momentarily depressing the Schrader valve located on the return (low pressure) line. If minimal or no pressure is present, then the system likely has an inadequate freon charge (as well as a leak) and is thus inactivated by the freon pressure switch.

If the system is charged, locate the freon pressure switch (two pronged switch adjacent to the inflow side of the receiver/drier), disconnect and jump the two leads; turn the ignition on and activate the A/C (no need to start the engine). If the compressor clutch is heard or seen to engage, then the freon pressure switch is likely defective.

BTW, has the evaporator ever been replaced?
Reply With Quote
Old 05-16-2001, 09:37 AM
Registered User
Join Date: Jun 2000
Location: Plano, TX
Posts: 2,512
Good post from jgll. I'll add one thing.

I'm not certain the a/c compressor clutch will engage
without the engine running. It likely depends on the
particular model/year of the car.

My 1987 124 uses the dreaded Klima relay to control
compressor clutch engagement. One of the functions of the
Klima relay - at least on diesel models like my car - is
to deactivate the compressor when engine RPM falls below
a certain level. In my car, the compressor won't engage
unless the engine is running at 600RPM.

Early Klima relays waited for 10 seconds after the engine
reached 600RPM to engage the compressor. This was really
annoying down here in Texas. The newer Klima relay I now
have installed seems more aggressive in engaging the
compressor, but I'm still certain it waits until the
engine is running.

As they say, YMMV.

- Jim
Reply With Quote
Old 05-16-2001, 10:40 AM
Registered User
Join Date: Mar 2000
Posts: 532
Jcyuhn is correct; on vehicles equipped with a single poly-V-belt, the engine will need to be running when attempting to check clutch function by means of a jumpered low pressure protection circuit. Earlier vehicles with a dedicated A/C compressor belt can be checked in an ignition on/engine off position.
Reply With Quote


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
Mass Air Senson, '92SL c4791p Tech Help 7 10-17-2004 01:20 PM
DTC codes? Insane Air Conditioner... mcollinstn Tech Help 6 08-28-2004 12:03 PM
Rebuild the clutch on a 560SL Air Pump? toms560 Tech Help 1 08-15-2004 05:45 PM
300e Air Conditioner Blower rvana Tech Help 1 06-19-2004 02:11 PM
Air conditioner question on 1980 240 D Ken Diesel Discussion 9 04-05-2000 09:04 PM

All times are GMT -4. The time now is 01:57 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page