I bought a 40 qt

Question

I bought a 40 qt Coleman thermo-electric cooler to use in a semi truck. It worked FINE for about a month--running 24/7 then the insides were all warm and I lost a bunch of perishable food! I bought a replacement motor at a truckstop, but the motor doesnt seem to be a match. The cooler in question is Model 564. the moter was a 564A, I believe. It was the ONLY one available at the time. whats wrong?