Choose your weapon

Doug Jacobs, a factory-trained BMW motorcycle mechanic, started Prospero's Garage as a favor to friends needing help with wiring harnesses on classic air-cooled BMWs, aka "airheads."

"A lot of guys I knew had BMW Slash 5s. Some needed help rewiring so I found some factory diagrams, made them more useful, and started sending them out." 

He soon formed Prospero's Garage as a side gig to his work as a tax accountant and made his enlarged, color-coded and laminated wiring diagrams available for classic British, German, Italian and Japanese cars, as well as BMW and Harleys. His offering expanded as time allowed and demand dictated, constrained mainly by availability of original factory diagrams used for reference. 

There are now wiring diagrams for over 800 makes / models of classic European, American, and Asian cars and bikes available for immediate shipment.

Hemmings Motor News

"My original Volvo service manuals include a foldout diagram of the stock electrical system. It’s complete and workable, but it’s all in black and white and nearly very difficult to read quickly. A quick Internet search turned up a handy alternative at colorwiringdiagrams.com. For $20, they shipped me a laminated 11-inch-by-20-inch diagram of the 1800E stock wiring drawn from scratch, color-coded and clearly labeled. I cannot exaggerate how useful this is for reference."  Steve Berry, Contributing Editor, Hemmings Motor News

Classic Motorsports
"It's not often that we seee a new product that really solves a problem in such an innovative way.  Restoring and driving classics can be a chore, one that's often exacerbated by aging electrics that fail at inopportune moments.  What's works is that many factory wiring diagrams are hard to read, are printed on pulp paper, and are filled with so many abbreviations that even a veteran mechanic will scratch their head in puzzlement.

Enter Prospero's Garage and their large, laminated and color-coded wiring diagrams.  The 11x17 inch format allows for larger type, and the laminated design keeps the diagram safe from greasy  fingerprints.  You can even roll them up and take them on road trips.  Prospero's Garage has diagrams for amny popular cars, including classics from Alfa Romeo, Austin Healey, BMW, Datsun, Jaguar, MG, Mini, Porsche, Triumph, and Volkswagen.

-July 2006

"I just wanted to commend you on the accuracy of this diagram. I really appreciate the amount of effort you put into getting the layout to match the physical reality as much as possible, too. I managed to disconnect a couple of the wires up by the glovebox on my 1972 Midget and lost my right rear turn signal as a result. Your diagram allowed me to easily diagnose where the problem was (I didn't realize that I had disconnected them) as well as find the offending connectors and see the problem. Unfortunately, it is harder than blue blazes to actually get the wires back into their proper connectors in there with no slack and no way to see what you are doing, but that isn't your fault, is it? In cross-referencing the diagrams in the Haynes manual, I found that yours were not only easier to read, but they more accurately depicted the connections involved both logically and physically. I never would have found this with the Haynes diagram.  Thanks again for all of the work that went into these!" - David L., 1972 MG Midget

"I got the wiring diagram today. It is the best I have ever seen. I have restored several classic bikes and always have a problem getting the wiring back the way it should be. Most times there have been some alterations through the years on the older bikes. I have tried taking detailed digital pictures, but even that has not been much benefit. Your wiring diagram is very clear and easy to understand. It is laid out in a very logical manner and is easy to follow. You have done a terrific job on it.  Thanks again for a very high quality, laminated document. I have left positive feedback for you and will recommend you to the other /5 owners I know." - Dennis P., BMW Slash 5 owner