Electric speedometer installation

From Crankshaft Coalition Wiki

[edit] Preamble

Most electric speedometers are installed in much the same manner as this installation. The speedometer is fitted into a dash or dash cluster with a tach, oil pressure, amps or volts, and temperature gauge. The use of an electric speedometer rather than a mechanical one eliminates the thick heavy speedometer cable housing that must be run from the dash through the firewall and back along the transmission tunnel to the transmission case. The threading of this cable back to the transmission often causes problems with steering linkage, exhaust headers, shift linkage and wiring harnesses.

The installation of the electric speedometer simplifies the whole speedometer process to three major parts; a speedometer head, a electrical harness, and a electric pulse sender unit. Wiring can generally be coupled with the console or radio speaker wiring and run along the center floor.

[edit] Speedometer Placement and selection

Choice of speedometer includes size, shape, face color, needle type, speed indicated, odometer and tripnometer, to name just a few. Placement is not limited to just the dash area and this is due to the fact that a wiring harness is more versatile than a mechanical cable.

[edit] Running wire harness and installing hardware

Run your wiring harness from the speedometer head to the sending unit at the transmission along with the console or radio speaker wire harness. Use a grommet when going through sheet metal. Always ground the harness to the sheet metal floor and dash bezel to avoid erratic behavior of the speedo. Run lighting off of existing gauge lights or come off headlight switch for brightness or dimming of lights. When installing sending unit at transmission, use a light coating of anti-seize on housing threads to seal out moisture and avoid over-tightening. Some sending units will include an end for mechanical cable connection to cable operated cruise control units. Weather-pac connectors should have a slight coating of grease to keep out moisture and keep electrical connections bright and corrosion free.