I had a similar issue with mine during a power outage last week. Lost power for 5 days and tried to run front AC, only rear worked. My MH is a 96 also the AC is Duo Therm with a 24 year old Duo therm thermostat. With out writing a novel about 3 days of trying to fix it it turned out to be the thermostat. The on of switch(heat, off, and cool) was loose and the little brass spring clips were loose and shorted out tripping my CB. When I remove the switch I saw it is held in place by only metal tabs and loosened over 24 years of use. I re bent the brass springs inside so they would make contact and re bent the switch housing so it would remain in place and got the front AC to work again. I don't know if this is your problem but I would look at the thermostat first. Hope this helps.
