Your first attempt was successful.
There should be a thermometer in that horizontal opening and itís not that accurate. The slider on the top is how you set the desired temp, and yeah, itís not that accurate either.
2012 Copper Canyon 273FWRET being towed by a 1994 Ford F350 CC,LB,Dually diesel.
Airlift 5000 bags, Prodigy brake control, 5 gauges on the pillar.Used to tow a '97 Jayco 323RKS.
Now an RVIA registered tech. Retired from Law enforcement in 2008 after 25+ yrs.