Eldest son and I did a little diagnostic work on the 92 300E 2.6 ACC tonight, and I want to run our findings by the group to see if the consensus is we're on target.
Complaint: No AC Presumed failure: AC compressor clutch coil Diagnostics: Checked for signal to coil - get it, but for just a second or two. Connected a new coil to the corresponding wire in the connector, leaving the Hall Effect transducer connected. With the engine running when the ACC is turned on, the coil energizes for maybe a second, evidenced by holding a screwdriver shaft next to it. Applying +12VDC to the existing coil results in nothing - no click, no spark at the terminal when power is applied, nada. Tests for both continuity and resistance indicate an open circuit. Based on my understanding of the ACC system in this car, the results we're getting show that if the compressor was turning when the system is turned on, the clutch would energize as expected. Because the compressor is not rotating, I am assuming the Hall Effect pickup on the compressor is "telling" the system to de-energize the clutch to prevent damage. Yes? No? A safe bet that we've got a bad AC clutch coil? We have the holding tool and puller courtesy of AutoZone, so we're ready to tear into this bad boy in the morning and get this poor sweating kid some AC. TIA, Dan _______________________________________ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
