The study examines a vapour absorption cycle with an ammonia-water solution through a thermodynamic analysis of the system using waste heat from truck diesel engines. An energy balance of a diesel engine shows that sufficient waste heat can be utilized to run an absorption refrigeration cycle. At the given parameters of the diesel engine and ambient, the obtained coefficient of performance is 0.3556 and the circulation ratio is 2.552. These results are manipulated using a range of operating conditions which maximizes the performance of the system. The results demonstrate that higher performance of the system is obtained at the high generator and low absorber temperature or vice versa to obtain the cabin temperature equals 20 C which is the prime objective..