98 3/4 Ton A/C will not turn on

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June 1st, 2010, 10:26 AM

chvaughan

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98 3/4 Ton A/C will not turn on

The suburbans system had some freon leaks including a clutch compressor leak. I ordered replacement parts, some of which I may not have needed. But since they were bought I had them installed. Parts purchased: Compressor Expansion valve Dryer Front hose assembly (between dryer and compressor)<O

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Replaced one of two AC hoses from rear to front of truck (small hose, bad\damaged connection) The story continues. So I take apart the rear portion of the HVAC system to install the expansion valve and notice the two hoses running from the rear to the front and see how they are installed. At this point I realize I do not have the time to complete this work before the weekend. So I take it to a mechanic friend. Everything is installed and all pressured up. AC button came on them went out and the smell of electrical burn smell. He Pull the head unit and found brunt resistor. Replaced head unit with new head unit. $200 bucks later same problem. The problem is the AC will not turn on & the **** that controls the vents will not change from foot to any other setting like face.<O

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So further trouble shooting by the mechanic indicated no signal from the computer (ECM\PCM) to turn on the AC system. The mechanic thinks the trouble is the EMC? I can get a refurbished ECM for $600.00 but I am unsure this is the right thing or the right diagnoses. HELP. Now I am at $650 in parts plus some $800 in labor and may need a $600 ECM\PCM. Please tell me what to have this mechanic check. I asked about the pressure switch on the compressor and he explained there was no voltage there to check since the system was not turning on.<O

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Last edited by chvaughan; June 1st, 2010 at 12:20 PM. Reason: GRAMMER