Tachometer Circuit Test

Using a DVOM, backprobe terminal No. 16 (Blue wire) at combination meter harness connector M41. See Figure . Start engine. Observe DVOM while changing engine RPM. If voltage reading increases at higher RPM, and decreases at lower RPM, tachometer circuit is okay. If voltage does not change in relation to RPM, repair open or short in Blue wire. See WIRING DIAGRAMS  .