2010 T660 no washer and only high wiper speed

[Truckdriven]

Yeah I believe that would be the chassis node, I had wiring issues with mine too, however I am not aware the the wiper system is connected to the chassis node unless like you said it causes some indirect/ghost issues. It would be controlled by the CECU under the cupholder, I would caution against replacing that controller until some one gets a wiring diagram and gets a good understanding of how the circuit works, then tests things properly with a voltmeter. As I said earlier a quick and easy test is simply replace the relays