825042 Mercury PLUG

Table 1
Wiring Faults and the Combinations of Cylinders that are Affected on 16 Cylinder Engines    
Wiring Fault     Affected Cylinders    
Open on the driver side     Only one cylinder is affected.    
Return side open    
Return side short to ground    
Cylinder 1 or 15
Short to +Battery on the driver side     1 and 15    
Cylinder 2 or 16
Short to +Battery on the driver side     2 and 16    
Cylinder 3 or 13
Short to +Battery on the driver side     3 and 13    
Cylinder 4 or 14
Short to +Battery on the driver side     4 and 14    
Cylinder 5 or 11
Short to +Battery on the driver side     5 and 11    
Cylinder 6 or 12
Short to +Battery on the driver side     6 and 12    
Cylinder 7 or 9
Short to +Battery on the driver side     7 and 9    
Cylinder 8 or 10
Short to +Battery on the driver side     8 and 10    
Return side short to +Battery     1, 3, 5, and 9    
2, 4, 6, and 10
7, 11, 13, and 15
8, 12, 14, and 16
Table 2
Wiring Faults and the Combinations of Cylinders that are Affected on 12 Cylinder Engines    
Wiring Fault     Affected Cylinders    
Open on the driver side     Only one cylinder is affected.    
Return side open    
Return side short to ground    
Cylinder 1 or 11
Short to +Battery on the driver side     1 and 11    
Cylinder 2 or 12
Short to +Battery on the driver side     2 and 12    
Cylinder 3 or 9
Short to +Battery on the driver side     3 and 9    
Cylinder 4 or 10
Short to +Battery on the driver side     4 and 10    
Cylinder 5 or 7
Short to +Battery on the driver side     5 and 7    
Cylinder 6 or 8
Short to +Battery on the driver side     6 and 8    
Return side short to +Battery     1, 5, and 9    
2, 6, and 10
3, 7, and 11
4, 8, and 12
Table 3
Wiring Faults and the Combinations of Cylinders that are Affected on 8 Cylinder Engines    
Wiring Fault     Affected Cylinders    
Open on the driver side     Only one cylinder is affected.    
Return side open    
Return side short to ground    
Short to +Battery on the driver side    
Return side short to +Battery     1, 4, 6, and 7    
2, 3, 5, and 8 Because the circuits are in pairs or groups, multiple diagnostic codes can be activated for a single problem. If multiple diagnostic codes are active for the primary ignition, troubleshooting the circuits one at a time is an effective way to find the root cause.The most likely causes of the diagnostic code are a poor electrical connection or a problem in a wiring harness. The next likely cause is a problem with an ignition transformer. The least likely cause is a problem with the ECM.
Illustration 1 g01251202
Schematic for the primary ignition on 16 cylinder engines
Illustration 2 g01251203
Schematic for the primary ignition on 12 cylinder engines
Illustration 3 g01251204
Schematic for the primary ignition on 8 cylinder enginesTest Step 1.