First separate the battery cable from its negative terminal while also turning off the anti-theft audio system lockout function on 4Runner models. Take these steps first: disable the airbags and then take apart the steering wheel and steering column accessories. Disconnect the electric connector from where wipers and windshield switch connect. Place the ohmmeter probes on specific wiper switch terminals to test their functions: for the mist wiper switch measure 7 and 16 connections in OFF mode while 7 and 17 connections in MIST and LO stance, also test 8 and 17 connections in HI pose. When testing the intermittent-type wiper switch you should measure electrical flow between terminals 7 and 16 while in OFF and MIST settings, between 7 and 17 in LO mode, and between 8 and 17 in HI mode. At Washer 1 you should find continuity between terminals 2 and 12 on the rear wiper switch test. There should be no continuity at the Wiper OFF position and you should detect continuity between terminals 2 and 13 at Wiper INT. You must test washer switch performance by measuring connection between terminals 2 and 11 while the switch is set to ON position. Replace the switch when it fails to work according to its design. After you detach the windshield wiper switch install it back into the switch body but make sure to put the spiral cable in the right position before aligning the steering wheel.