1999 32' Holiday Rambler 30amp 2 Duo-therm A/C units. Plugged into 30amp service camping for 3 days alternating front & rear A/C all fine. 3rd day A/C units quit working. All other 120v appl. still fine. No breakers tripped. While at home a day later tried running A/C's again, both worked (alternately) for a short time but soon quit working again. No problems leading up to this 2nd trip requiring A/C running all day. Have tried all troubleshooting I know of, any suggestions?