Madsen's Auto Tech is a complete auto service shop that specializes in custom work on hot rods and air conditioning, heating and electrical repairs. Experts in this shop have the experience and know-how to build any kind of car, especially hot rods, from top to bottom. They are also sleuths at tracking down problems related to electrical, heating and electrical systems. Other services include oil changes, transmissions, brakes, tuneups, clutches and general engine repairs for domestic and foreign vehicles and also big rig trucks. Owned and operated by Mike Briard, this shop was originally located in Concord for 25 years, but has been situated at the corner of Shell Avenue and Pacheco Boulevard since 2008. This shop offers free diagnosis and estimates in most cases.