2004 Hummer H2 Rear Window Washer and Wiper Run all the Tim

My 2004 Hummer H2's rear window washer and wiper run all the time even with the switch off. The only way I can turn off the rear washer and wiper motor is to set the front wipers on the "high" setting. The rear wiper and washer run on any other setting on the front wiper switch. I can control the rear wiper and washer when the front wipers are on the high setting, any other combination causes the rear wiper and washer to run as long as the vehicle is running.

I disconnected the rear wiper switch connector from the rear wiper switch on the dashboard to see if I can get the rear wiper and washer to stop. This did not work. Both the rear wiper and washer continued to run with the rear wiper dashboard switch harness connector disengaged. I tested the washer relay in the engine comaprtment fuse block and it tested fine. I had to disconnect the rear wiper module and washer connectors in the tailgate in order to get the rear wiper to stop running. I also had to remove the washer realy in the engine compartment to stop the rear washer from running.

Is this a front windshield wiper motor module issue? Is the wiper module part of the front wiper motor? Anything else?

Thank You.