In my fsm it mentions alot about checking ground activation. How do I do this using a multimeter? do I check ohms, voltage, amps. does one probe touch ground or do both probes touch the circuitry? do I need to be on both ends of the circuit?

I need a multimeter for dummys! My Sears multimeter manual does'nt tell me much and my electrical troubleshooting skills are weak!

Help electrical gurus!

Thanks

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1993 Mercedes Benz 300D 2.5 205K (ex wife's)
1984 Mercedes Benz 300SD 320K (SOLD)
2004 Mercedes Benz C240 75K
1995 GMC Sierra 2WD 5.7L 188K
1983 Mercedes Benz 300SD 239K (SOLD)
1987 BMW 325i 220K (SOLD FOR SALVAGE)

609 Certification

Ground activation should be chaecked using a multimeter set on the voltage setting. Set the voltage range on 20V.

Put the red (+ ve) terminal on the battery. Put the black terminal (- ve) on the point at which you want to test ground activation.

If the ground activation works, then you will read battery voltage (close to 12V) on the meter. If the ground activation does not occur, then you will read anything but close to battery voltage.

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Saumil S. Patel

thanks saumil, that's exactly the info I need!

on a 2 prong component like the mono valve and aux water pump, does it matter which prong I touch with the black (common) probe? can I check wires/plugs this way also?

__________________
1993 Mercedes Benz 300D 2.5 205K (ex wife's)
1984 Mercedes Benz 300SD 320K (SOLD)
2004 Mercedes Benz C240 75K
1995 GMC Sierra 2WD 5.7L 188K
1983 Mercedes Benz 300SD 239K (SOLD)
1987 BMW 325i 220K (SOLD FOR SALVAGE)

609 Certification

On a two terminal connectors, if you know one of the terminals is going to be set to ground (when something else happens, say the climate control unit sets the monovalve's terminal to ground to open the valve) and the setting of ground is going to cause the device to operate, then one of the terminals would be this "control" terminal and the other terminal is likely to have power voltage or ground depending on the function and design of the device. So if you dont know which of the terminals is the "control" terminal, you could try both terminals with your black probe (one at a time) BUT only for one terminal you would get battery voltage when the ground is activated. For the other terminal you could get either battery voltage or no voltage, but will be fixed, would not change based on the external control (i.e. the climate control's setting). Hope this helps.

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Saumil S. Patel