[PDF] INSTALLATION INSTRUCTIONS 5 Tachometer INSTALLATION INSTRUCTIONS 5" Tachometer 2650-1244-00 Rev. B QUESTIONS: If after completely reading these instructions you have questions regarding the operation or installation of your instrument(s), please contact Auto Meter Technical Service at 866-248-6357. You may also email us at service@autometer. Resources - Installation Support - Auto Meter Resources. Installation Support. INSTRUCTIONAL DOWNLOADS. Find product manuals and wiring diagrams for your Auto Meter product. While proper grounding of the tach and routing of the signal wire go a long way towards preventing this, sometimes it's not enough. Follow along with the AutoMeter crew as we remedy this problem.