Resurect an old thread I kept as a favorite. In 4/2011 I bought a new 6535-344 thinking I had a bad thermostat. Turned out to be something else (I wish I remembered what it was two years later!) so I never installed it. Fast forward two years and my a/c won't shut off unless I trip the breaker. So I think I will throw the new one in to see if that was the problem. Go to install it and one of the connectors has 4 pins instead of 3. I remember there is a thermostat thread somewhere. Look through my favorites (under my subfolder TIPS under my favorites folder RV) and there it was. How to work around that 3 vs 4 pin issue. I did exactly what the OP ended up doing and now it works---exactly as it did before.
Thanks elwestbro, if you are still out there, for the tip.
So I will save my old stat as a spare and go looking elsewhere for the problem.
Ole and Anne Anderson, Highland, Michigan
'02 Adventurer 32V, Ford F-53, ours since 4/08,Goodyears, Konis, SeeLevel, CHF
'84 CJ-7 , 5.3 Chevy, 3" lift, 33's, Detroit Locker, Fiberglas tub, winch, hi-lift