Clarion Ungo Pro Security RK1, Installation Manual

Page: 9 / 46

9
finding the accessory/heater wire
An accessory/heater wire will show +12V when the key is in the accessory and run positions. It will
not show +12V during the cranking cycle. There will often be more than one accessory wire in the
ignition harness. The correct accessory wire will power the vehicle's climate control system. Some
vehicles may have separate wires for the blower motor and the air conditioning compressor. In such
cases, it will be necessary to add a relay to power the second accessory wire.
finding the RPM input wire
To test for a tachometer wire, a multimeter capable of testing AC voltage must be used. The tachome-
ter wire will show between 1V and 6V AC. In multi-coil ignition systems, the system can learn indi-
vidual 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 non-common fuel injector control wire for
engine speed sensing. Common locations for a tachometer wire are the ignition coil itself, the back
of the gauges (if a tachometer is present), engine computers, and automatic transmission computers.
IIM MPPO ORRTTA AN NTT!! Do not test tachometer wires with a test light or logic probe. The vehicle will be damaged.
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 fluctuate with the rpm of the motor and 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. Some vehicles employ a data line (rather than analog) from the ECM which may
require an additional timer.