93' Explorer will not turn over - How do I test the Ignition Switch

[DGrant09]

We have a 93" Explorer with good battery power, clean battery terminals, good starter (tested), a new starter relay and she still will not start. No engine rotation..
The truck was fine when I was installing snow tires and before, I backed it out of the garage after the tire change over and now it will not start. It was suggested to test the ignition switch, does anyone have reference to this test? I can only find replacement procedures... Any other useful suggestions would be deeply appreciated!!
Thanks
Dan

 

[Karmana]

Have you tried jumping it across the terminals on the solenoid (on the firewall) with a screw driver? I would check that, and also the small push on wire at the starter itself, to make sure that hasn't slipped off.

 

[94Sport5Sp]

The purpose of the ignition switch is to is to xfer power to the solenoid (usually located on fender well passenger side). To test that this is working put a test light on the smaller terminal and have someone turn the ignition switch. If the test light comes on then ignition switch is good.

Usually the problem is the solenoid and as Karmana suggested you can cross the connectors on the solenoid to test starter. (See http://www.explorerforum.com/forums/showthread.php?t=168889 for picture of solenoid.) A hot wire on the larger connector (single wire) will provide power to starter and starter, if good, should spin. A hot wire applied to the smaller connector will test the solenoid and if good the starter should spin.

 

[DGrant09]

Thanks for the quick replies and advice.. I learned some more trouble shooting ideas from them.
I re-installed the starter this evening from being tested and the truck started.. I will not have to replace the ignition switch as I was thinking of doing next.. Instead I beleive the problem is in the wiring - corroding from the inside out as mentioned in several other posts. The truck has 260,000 miles now and this would not be a surprise.. So we'll take the switch back and exchange it for some new starter wiring..
Thanks Again!!