Ground Testing of the Idle Speed Micro Switch

[doctorDHD@xxxx]

The "condition" you described is the fact that the idle speed microswitch 
does indeed open and close but when fully connected the black with green stripe 
wire seems to always be grounded. This is the same in my case and I believe is 
proper but may be confusing. If you look at the wiring diagram you'll notice 
that the black with green wire is directly connected to a capacitor AND to 
the vacuum solenoid. The other side of the vacuum solenoid is connected tofuse 
number 1, along with the fuel pump, RPM relay, Idle Speed ECU and the 
ignition ECU. These all provide a path to ground that makes you think the idle speed 
switch is not working when you check continuity with the engine off. The 
better way to test it is put a volt meter across the idle speed switch. With the 
ignition switch ON but the engine not running (for safety) you should measure 
0 volts at throttle closed, ie idle and about 12 volts when the throttle is 
opened and the switch opens. You should also be able to hear the vacuum 
solenoid click, ie switch when you open the throttle. Unplugging the vacuumsolenoid 
allows you to check the switch using the continuity method because it 
isolated the switch from those other circuits. Let me know.

Thank you,

Dave & 6530

ps Please take a look at my invention at www.tvpedaler.com and let me know 
what you think.


"Just Say NO, to the COUCH POTATO!"®


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