I too have a set of TPI Tech gauges and have had several problems with them, however none with the speedometer. After much research I found the gauges are manufactured by the Thomas G Faria Corp. 385 Norwich New London Turnpike P.O. Box 983 Uncassville Ct. 06382 Phone 860-848-9271. I contacted this company and found them to be very helpful and very knowledgable, much more so than TPI tech's service department. Good Luck.