80-JB566-1 Rev. G
21-1
MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION
21
Ignition On Detection Problem
Problem: Ignition On Test Fails
1.
If the Ignition On test fails, ensure the truck’s ignition switch is in the ON position and
confirm:
•
The ignition lead of the Power/IO cable is secure.
•
The fuse in the ignition wire has not blown.
2.
If it continues to fail, check the ignition source used and the associated truck fuse.
Using a digital volt meter, verify that the source has approximately 12 VDC when key is
in the ignition ON position and shows 0 VDC in the OFF position.
WARNING
You must connect the MCP50 ignition wire to a true switched ignition source, not an
accessory source.
To confirm a true ignition source, use a digital volt meter to verify that the source has
approximately 12 VDC when the key is in the ignition ON position and shows O VDC in the
OFF and accessory position.
Note
: Many newer model trucks have multiplex wiring systems that require specific ignition
connection points. To ensure correct ignition connection points, refer to the individual Truck
Specific Installation Instructions for more details.
