Highlander weak heating output

I have a Highlander too (don't know the exact year), and I had a similar problem with weak heating. It could be a defective cable or plug connection, which might cause those issues.

Interesting. Was your error code pointing directly to the water valve too? Or was it something more vague?

The error pointed in the direction of the valve, however, I suggest you have the car checked in the workshop. In my case, they figured out a defective cable connection and charged 95€ for the repair.

Thanks for the info. I'll take it to the shop and mention the cable connection. Hopefully, it's a cheap fix like yours was!