engine won't heat up

Hello all. I've got this check engine light that is on and it turns out that it is a 'coolant temperature low' warning. The engine won't heat up while i'm driving but will heat up in the garage. I am in michigan so it gets pretty cold. The thermostat seems to work fine.

As to be the thermostat.
It's the only thing that open and close to let or not the water flow.

Turns out the thermostat was bad. It cost an ungodly 240 dollars to replace. What a joke.

Welcome to the buick owner circle.
And wait t'ill you'll have a wheel bearing or tie rod defective
or a knocking 3.4 engine.

240 bucks for a thermostat, what?

You could have done it yourself, part cost about $8 from a parts store and would only taken 1 hour to replace.....did you get ripped off.

2 things : 1st: Electric rad fan stays on (what I doubt)
2nd :Thermostat from previous reply : only the thermostat open & close, and yours stays open
You proved it by saying; when driving outside rad breath fresh air and cool off too much and when inside rad breath warmer air.
Too bad the thermostat is hidden under the crossover exhaust that you have to remove to get the thermostat out (costly repair) for a cheap part