80mm Car Modified LED Tachometer with Self-check Function 1. Independent instrument, no control unit required. Installation: red positive, black wire is negative, yellow light is positive power wire, white wire then turn signal wire number, or connect to ignition coil negative (negative ignition coil wire), also can connect to signal wire to crankshaft position sensor we It is generally recommended that car owners go to a repair shop or refit shop to complete the installation of the tachometer, because the line is distributed differently for each model, unless the car owner knows the speed signal line of their car, you can install it yourself. 2. Functions: power-on self-test, seven colors freely switch, peak value record, cylinder position setting, alarm value setting, upper alarm and lower alarm, large screen display 3. There are seven different backlights to choose from: redbluewhiteyellowgreenvioletcyan 4. Applicable models: 12V universal 5. Note: The tachometer can be installed on a 1-8-cylinder 12v gasoline car and cannot be installed on a diesel engine.