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Old 04-29-2009, 02:00 PM
Bio Diesel fool Bio Diesel fool is offline
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Join Date: Mar 2009
Posts: 12
Question No A/C, Kickdown, tach

Traced to combo control unit, replaced but still not working
Any ideas?
Thanks for reminding me that no one can help without the necessary Info.
Here is where we are at. 1992 300D 2.5 turbo Diesel 602.962
Vin WDBEB28DINB644488
Back ground just rebuilt and reinstalled engine runs great but no A/C limited kickdown no Tach.
Fuses all ck OK
Wiggled A/C Compressor Control Unit A/C compressor kicked on but lost all Trans Kick down.
Current conditions A/C, tach, trans kickdown all Inopperable
Checked; power supply to terminal 1,ground terminal 1, continuity to A/C cllutch from terminal 7 all OK. A/C clutch operates if #7 is powered.
Checked ground signal to terminal 10 through high pressure switch OK.
Terminals 9 & 11 show open untill Relay is installed & than a varring ground signal
Terminal #2 shows ground
Terminal #6 shows open
Terminal #4 shows weak ground that gets better @ WOT.
Don't know where to check from here.
Replaced A/C compressor control no change

Last edited by Bio Diesel fool; 04-30-2009 at 01:04 PM. Reason: Up Dated troubleshooting info
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