Need to test ignition switch for continuity - Help!

[pkemeralds]

Through the process of elimination we have come down to testing the ignition switch on our Mariah. I have a Mercruiser manual, with diagrams for testing and a digital multimeter but what kind of readings am I looking for in ohm? And what ohm setting do I use?
The manual calls out to test the terminals through the 3 stages of ignition for different continuity between terminals. I really just need to know how to use this multimeter correctly.
Also if it helps, the slave solenoid clicks, but there's no response at the starter. We put on a new starter, slave solenoid, new marine battery and all connections were cleaned.
The ignition switch continuity test is the last suggestion the boat mechanic recommended.

Need advice,
thanks
pk

 

[PondTunes]

Re: Need to test ignition switch for continuity - Help!

Seems like he would have recommended testing things before swapping parts but that's beside the point.

To test for continuity your meter may have a dedicated continuity setting (it's normally near the diode test setting and will make a tone if you touch the ends of the leads together)

If you don't have a dedicated continuity setting disconnect the battery and pick one of the ohm scales. A circuit that is open (no continuity) will read infinity between the leads. A circuit that is closed (has continuity) will show some resistance.

Remember: Don't touch the metal part of the probes when measuring resistance (ohms) or continuity. If you do it will display the resistance of your body, which will give you an incorrect reading.

 

[wire2]

Re: Need to test ignition switch for continuity - Help!

For switches and contacts, use the R x 1 setting. You should see 0 Ω (no resistance) from ignition supply to whatever it's set to. At that setting, it won't matter if you touch both leads with your fingers.

A lot of digital Ohmmeters show .1 or .2 Ω with the leads touched together, consider that to be 0 Ω when you're testing a switch.

Remember to disconnect the battery when using an Ohmmeter on 12v circuits. The meter itself supplies the power to get a reading.

 

[jtexas]

Re: Need to test ignition switch for continuity - Help!

Lot of multimeters, the continuity tester is the same setting as ohms, with a button you push to activate continuity mode - the button has a symbol looks vaguely of like this: o)))

Also, just to expound on wire2's comments, ohm meters typically use a display reading of 0.L to indicate no continuity, or infinity resistance, which is the opposite of 0Ω, or no resistance.

 

[wire2]

Re: Need to test ignition switch for continuity - Help!

>>ohm meters typically use a display reading of 0.L to indicate no continuity, or infinity resistance,...<<

Right, which implies "Out of Range" but you can't display an "R" with a typical 7 segment display.

 

[Boatin Bob]

Re: Need to test ignition switch for continuity - Help!

I'm still stuck on this from the first post Also if it helps, the slave solenoid clicks, but there's no response at the starter. Normally if the slave clicks then the switch is working?

 

[rickdb1boat]

Re: Need to test ignition switch for continuity - Help!

I would have someone turn the key while you measure voltage at the solenoid...

 

[jtexas]

Re: Need to test ignition switch for continuity - Help!

bob and rick, guess you didn't get the memo.......today we only answer the questions actually asked; ignore any other information, and no reading between the lines!

ya, faulty switch = solenoid no clicky. Hope you kept the old parts, they're probably still good. Did you say new battery? measure the voltage - no telling how long it was on the shelf - fully charged is at least 12.65 volts.

 

[Boatin Bob]

Re: Need to test ignition switch for continuity - Help!

Sorry jt...I'm always one of the last ones to get any memo's

 

[wire2]

Re: Need to test ignition switch for continuity - Help!

A solenoid click is a good sign, but not a guarantee that it's working.
Verify that you have 12v on the upper large stud, have someone "start" at the key.
The solenoid should click AND place 12 v on the lower large stud going into the starter.

Yes? And starter not running? Defective starter.

No? Defective solenoid.