Dash A/C not working...advice, please ?


  #1  
Old 10-04-18, 07:21 AM
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Dash A/C not working...advice, please ?

This is a 2003 motorhome on a W22 chassis and 8.1L Chev engine. Dash unit is a Evans Tempcon RV218552. R134a.

Only ambient air comes out when in A/C mode. It buzzes for 3 seconds and goes silent for 5 seconds. Over and over........endlessly.

Heater works OK but same symptoms occur.

My guess is a bad thermostat or low R134a....but I am a documented automotive dunce.

Any help is appreciated. Evans Tempcon no help.
 

Last edited by YaddaYadda; 10-04-18 at 07:24 AM. Reason: addition
  #2  
Old 10-04-18, 04:25 PM
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If the compressor clutch kicks in and is turning, one of the lines coming from the compressor should be very cold. If not, probably low on freon.
 
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Old 10-04-18, 06:02 PM
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That is a cable-less (electronic) system.
What is buzzing...... the dash unit ?
Low refrigerant wouldn't cause a problem in heat mode.

These are not easy units to repair. In the link..... you pick your dash control and then click on it.
Troubleshooting guides are listed for each unit.

Evans Tempcon service
 
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Old 10-04-18, 08:16 PM
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Thanks for the two replies. PJ.....This might be a cable system, RV218467. I can't tell. Does it make a difference in your diagnosis ? Buzz seems to be coming from under dog house.
 
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Old 10-05-18, 07:00 AM
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Besides the compressor/Freon that you already suspect, that cyclic buzz could be a stuck motor-driven damper door on the HVAC distribution box under the dash.
 
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Old 10-05-18, 12:21 PM
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Thanks to all who have replied. I will take to a service center...this is not a DIY for me.

Had a friend go under the coach with A/C running. He saw belt/pulley jump a bit in concert with the buzzing noise. Felt both A/C hoses and one was not colder than the other. Ambient air was 50 deg and incoming dash air was 46 deg.

Does this help ?
 
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Old 10-05-18, 05:09 PM
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I have serviced those units. I don't recall one ever buzzing so I'm not sure what is buzzing there. On the link page I left you...... are pictures of the control units. You pick yours out of the pictures and that's what system you have.

It sounds like the dash unit has a problem and is cycling the compressor.
 
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Old 10-21-18, 07:14 AM
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Went to local auto repair center. No R134a. Re-filled and ran A/C and checked with a black light. No leaks...apparently. Time will tell. They thought compressor shaft seal had dried out ....as I did not use in 6+ months.
 
 

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