Listed below are several common solutions to this issue:
- Check connections related to the signal wire (Green wire in most cases). Is the Green wire connected to the proper location (i.e. the negative side of the coil, or tachometer output from an after market ignition)? For further information about Tachometer signal location on your vehicle please see the Installation Information or Ask a Question sections of our website.
- Check power to the Red wire. It should register 12 volts (or higher) when checked with a voltmeter with your key on and with engine running. If not, check connections and try a different power source.
- Check power to your Black ground wire. If the illumination light also does not function, then the ground is a very likely candidate. To check your ground with a voltmeter, connect the positive of the meter to a known good power source then hook the negative of your meter to the black wire. You should get a reading, of 12 volts or higher. If not, check connections and try a different ground source.