2019 RTL won't shift up (fixed'ish - only now it's un-fixed again!)

[IdahoMtnSpyder]

Yes they replaced the entire left side cluster under warranty already trying to fix it part #710008164. Brake light modulators were disconnected before I left the shop on Saturday.

That deepens the mystery. I didn't realize you already had the LH switch replaced. My next bet would be a broken or shorted wire or loose or wet connector somewhere in the harness. But then again the fact that several others have had this problem would tend to discount this possibility, except connectors getting wet. Everyone rides in the rain sometime! After that I would consider the replacement switch module is defective, or the transmission control module has a problem. Try to get the shop to replace the TCM and see what happens.

[Peter Aawen]

That deepens the mystery. I didn't realize you already had the LH switch replaced. My next bet would be a broken or shorted wire or loose or wet connector somewhere in the harness. But then again the fact that several others have had this problem would tend to discount this possibility, except connectors getting wet. Everyone rides in the rain sometime! After that I would consider the replacement switch module is defective, or the transmission control module has a problem. Try to get the shop to replace the TCM and see what happens.

Orrr, maybe they pinched a wire or two when they replaced the LH Cluster... or didn't plug it in properly??