TCU Output Wiper Relay Circuit

Turn ignition switch to the ACC position. Using voltmeter, backprobe TCU connector. Connect positive voltmeter lead to terminal No. 1 and negative lead to terminal No. 15. With wiper switch in OFF position there should be battery voltage. With wiper switch in INT position, voltage reading should change every 3 to 23 seconds from zero to battery voltage. If switching does not occur, check wiper switch circuit. If voltage reading switches as indicated but wipers are still inoperative, check wiper relay and relay circuit.