So my moms got a 02 buick rendevous it's has an overheating issue. Ima list the issue and it's tech.

3.4l transverse mounted v6 with 165k on body and trans unknown on motor

Issue as follows
Normal idle an start after warming up the temp gauge will rise to 3/4 but not past when siting however if you begin to drive say highway or even city it goes down I assume due to airflow to motor. I know the fans work we jumped them and they started up no problem however they don't kick in on their own like they should.

Parts that have been replaced.
Fan relays
Temp sensor


If anyone has knowledge or expirenced this issue and had a solution other than throw parts at it would def appreciate it soon to be I'm goin to wire the things up to a separate temp switch mounte to radiator somehow to kick them on at 195degress