Results 1 to 3 of 3

Thread: a/c compressor clutch doesn't engage

  1. #1
    Join Date
    Nov 2004
    Location
    Santa Barbara, CA
    Posts
    132

    Default a/c compressor clutch doesn't engage

    I just purchased a 1990 535i and the a/c clutch doesn't engage. The a/c push-button on the dash lights, but the clutch does not engage. Normally I would expect this is due to loss of refrigerant and the low pressure switch is cutting power to the clutch.

    Since I can't just take it over and get a shot of R-12, however, I wanted to try and trace down the power to the clutch first, and see if the problem is electrical. Are there any known failure modes on this system? The low pressure switch? Relay? a/c control button? Any insight would be appreciated before I head out with the multi-meter.

    (Ordered a Bentley manual, but has not arrived yet, and I need to try and sort this out over the weekend)

    Thanks to all.

  2. #2
    Join Date
    Jan 2005
    Posts
    107

    Default

    Keep the multi-meter handy. Do you have a set a A/C gauges? You could hot wire the compressor and watch the system pressures to determine if it is low on R-12. Some people have topped them off with pure propane.

  3. #3
    Join Date
    Dec 2003
    Location
    Eastern Tennessee USi
    Posts
    14,821

    Default

    there s a low pressure cut off switch that you can jump to see if the compressor works. Check for power on one side and nothing on the other and then jump it.
    95 E34 530I V2.37
    ===========
    Those who make peaceful revolution impossible will make violent revolution inevitable.

    John F. Kennedy

Similar Threads

  1. 540 A/c Compressor clutch
    By yaofeng in forum 5 Series BMW
    Replies: 6
    Last Post: 04-16-2008, 11:58 AM
  2. Replies: 5
    Last Post: 07-30-2007, 08:39 PM
  3. do i need a compressor or clutch or both???
    By tim s in forum 5 Series BMW
    Replies: 4
    Last Post: 06-09-2007, 03:08 PM
  4. Air con not working, compressor doesn't engage
    By Paul_540i in forum 5 Series BMW
    Replies: 7
    Last Post: 04-03-2005, 01:07 PM
  5. Replies: 2
    Last Post: 05-08-2004, 11:45 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •