This paper is a result of some investigation work into the quality of electrical components, wiring, connectors and their installation into heavy commercial vehicles. The investigation covered a range of vehicle types including rigids, articulated tractors and trailers and bus and coach. It looks at the implications and potential cost to operators of vehicles being unavailable for work, the impact of poor or no electrical supply on other vehicle components, identification of the major defects and problems associated with components, wiring and connectors, and some views on how these may be improved.