Mercruiser manual pin testing technique

[Merc4ever]

Mercruiser manual says:

ECM Connector and EFI Symptoms Chart
The following charts will aid in diagnosis of symptoms. These voltages were derived from
a known good engine. The voltages shown were done with the electrical system intact and
operational. These are voltage requirements to operate the different circuits.
CAUTION
Do not attempt to obtain these voltages by probing wires and connectors. Serious
damage could result in loss of engine operation or wiring damage. Voltages can
vary with battery conditions.


Then what is the technique for testing these points?

 

[alldodge]

The caution is so you don't use a probe to pierce thru the wires or connectors while running. With the engine off you disconnect the connectors, then turn the ignition on and measure the contact points.

 

[Merc4ever]

I guess I get hung up on the don't probe connectors part? I can't imagine anyone piercing through a connector attepting to hit a certain pin out of many.