Kent Madison Posted March 21 Share Posted March 21 On my 09 holiday rambler navigator Bismark 4 the dash AC works some times and not some times. I had the same problem with the wipers so I installed the 5V fix and that corrected the wiper problem. I am wondering if the Dash AC is also ran through the front CCM and if the low voltage that front CCM is providing could be part of the problem. I have checked all the fuses and they are good and I put in a new AC condenser fan a few months ago. Getting ready to travel south for a few weeks and would really like the AC working. Any suggestion on if I need to add the 5Volt fix to the front AC CCM wires like I did for the wipers? Thanks Link to comment Share on other sites More sharing options...
jacwjames Posted March 21 Share Posted March 21 What stops working, does the fan quit or does it stop cooling? Link to comment Share on other sites More sharing options...
Kent Madison Posted March 21 Author Share Posted March 21 The fan blows but the AC clutch will not engage and the condenser fan will not run. Link to comment Share on other sites More sharing options...
jacwjames Posted March 21 Share Posted March 21 When was the last time you check the refrigerant pressures, if it is low on refrigerant the compressor will not run. You should be able to check by jumping the low pressure switch. When I first bought my 2002 Windsor in 2008 the AC would not run. I added one can of refrigerant and it took off and ran until ~2018. I then had to add a little. In 2021 I bought a cheap set of gauges to check and my neighbor who's a HVAC guy sold me a large canister of freon and help me check it. Late last year the AC didn't cool as good as I would like so checked it a couple weeks ago and had to add a little. At some point I may have to tear into it and look for a leak but adding a little every 3 years works for me. It would take a lot of $$$ and to completely rebuild the system. Link to comment Share on other sites More sharing options...
Frank McElroy Posted March 21 Share Posted March 21 1 hour ago, Kent Madison said: On my 09 holiday rambler navigator Bismark 4 the dash AC works some times and not some times. I had the same problem with the wipers so I installed the 5V fix and that corrected the wiper problem. I am wondering if the Dash AC is also ran through the front CCM and if the low voltage that front CCM is providing could be part of the problem. I have checked all the fuses and they are good and I put in a new AC condenser fan a few months ago. Getting ready to travel south for a few weeks and would really like the AC working. Any suggestion on if I need to add the 5Volt fix to the front AC CCM wires like I did for the wipers? Thanks On your coach, the HVAC gets power from the 30 amp fuse VCE5/6 on the large PCB in the FRB. It is not powered through the CCM like the wipers. Link to comment Share on other sites More sharing options...
Kent Madison Posted March 21 Author Share Posted March 21 PCB in the FRB???? Not sure that this means. Sorry Link to comment Share on other sites More sharing options...
Frank Bergamo Posted March 21 Share Posted March 21 Circuit Board in the Front Run Bay. Front Run Bay is located outside, under driver position. Good luck. Link to comment Share on other sites More sharing options...
Kent Madison Posted March 21 Author Share Posted March 21 Thanks Link to comment Share on other sites More sharing options...
Kent Madison Posted March 21 Author Share Posted March 21 it ended up being this temperature switch. Tapped on it and it started cycling like it should. Thanks everyone for the help. Link to comment Share on other sites More sharing options...
Ivylog Posted March 22 Share Posted March 22 16 hours ago, Kent Madison said: it ended up being this temperature switch. Tapped on it and it started cycling like it should. Thanks everyone for the help. I take the plug off that and insert a 15A fuse in the plug bypassing it so the compressor runs all the time. Yes, it will freeze up the evaporator BUT out West it usually takes 7+ hours before the airflow decreases enough to notice. In the East it can be 4-5 hours so I turn the AC off with the fan on high for 15-20 minutes (still get cool air as it defrosts) and then turn the AC back on…rarely have to run the generator, 1 Link to comment Share on other sites More sharing options...
Kent Madison Posted March 22 Author Share Posted March 22 I might try that if I need more cooling. Thanks Link to comment Share on other sites More sharing options...
96 EVO Posted March 22 Share Posted March 22 That evaporator temp control switch failed on mine as well. There was plenty of corrosion on the spade connectors. Link to comment Share on other sites More sharing options...
Kent Madison Posted March 23 Author Share Posted March 23 Thanks Link to comment Share on other sites More sharing options...
Happycarz Posted March 25 Share Posted March 25 http://acmeairparts.com/rvacheaterparts.html Link to comment Share on other sites More sharing options...
96 EVO Posted March 25 Share Posted March 25 13 minutes ago, Happycarz said: http://acmeairparts.com/rvacheaterparts.html Yeah, I may need to tweak the adjustment screw on my new one. Not looking forward to getting at the mounting screws, again 😣! Link to comment Share on other sites More sharing options...
Kent Madison Posted March 25 Author Share Posted March 25 Thanks Link to comment Share on other sites More sharing options...
Happycarz Posted March 26 Share Posted March 26 As Ben said, you can adjust these thermostatic switches. GM used these same switches 50 years ago. The capillary bulb on the end of the tubing monitors the evaporator temperature and applies pressure against a spring loaded set of contacts. If the evaporator gets below freezing, the contacts open, turning off the compressor clutch. Once the temperature rises and the capillary bulb pressure drop below the spring rate, the contacts close and the compressor engages. Using a small Torx, or even a flat bladed screwdriver, you can adjust the cycling temperature up or down from the outside of the thermostatic switch. But since the adjusting screw is out of sight, toward the firewall, it would be wise to unscrew it while trying the different adjustments. Once happy with the cycling temperature, screw it back on the evaporator box.. Yellow arrow points to adjusting screw on end of spring . 1 Link to comment Share on other sites More sharing options...
Kent Madison Posted March 26 Author Share Posted March 26 Thanks. I now know how to fix it if it acts up again. Link to comment Share on other sites More sharing options...
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