Finding The Tachometer Wire; Finding The Wait-To-Start Bulb Wire For Diesels - Clifford Matrix RS2 Installation Manual

air bag, avoid disconnecting the battery if possible. Many airbag systems will display a diagnostic
code through their warning lights after they lose power. Disconnecting the battery requires this
code to be erased, which can require a trip to the dealer.
➤ ➤
Check with the customer on LED status indicator location.
➤ ➤
Remove the domelight fuse. This prevents accidentally draining the battery.
➤ ➤ Roll down a window to avoid being locked out of the car.

Finding the Tachometer Wire

To test for a tachometer wire, a multimeter capable of testing AC voltage must be used. The tachometer
wire will show between 1V and 6V AC. In multi-coil ignition systems, the system can learn individual
coil wires. Individual coil wires in a multi-coil ignition system will register lower amounts of AC
voltage. Also, if necessary, the system can use a fuel injector control wire for engine speed sensing.
IMPORTANT! Do not test tachometer wires using a test light or logic probe! This will
damage the vehicle.
How to Find a Tachometer Wire With Your Multimeter
1. Set to ACV or AC voltage (12V or 20V is fine).
2. Attach the (-) probe of the meter to chassis ground.
3. Start and run the vehicle.
4. Probe the wire you suspect of being the tachometer wire with the red probe of the meter.
5. If this is the correct wire the meter will read between 1V and 6V.

Finding the Wait-To-Start Bulb Wire for Diesels

In diesel vehicles it is necessary to interface with the wire that turns on the wait-to-start light in the
dashboard. This wire illuminates the bulb until the vehicle's glow plugs are properly heated. When
the light goes out the vehicle can be started. This wire is always available at the connector leading
to the bulb in the dashboard. It can also be found at the Engine Control Module (ECM) in many
vehicles.
How to Test and Determine the Polarity of the Wait-To-Start Wire
1. Set your multimeter to DCV or DC voltage (12 or 20V is fine).
2. Attach the (+) probe of the meter to (+)12V.
3. Probe the wire that you suspect leads to the bulb with the (-) probe of the meter.
4. Turn the ignition switch to the ON position.
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