It's way cheaper to just get vent visors for your windows at $55 and drive with the windows open a tad when it's raining then to play with the diverters which are plastic-attached probable to plastic servos-attached to plastic housings-get the drift. Its not like my moms 71 Bonneville Battle Tank was with metal control rods attached to metal diverters. Plus that came with a Caddy 500cid motor and weighed more than 2 of our HHRs-talk about gas wasting.

Mike

 

I see where the diverter valve is. Be a real job to get to. Just have to wire a compressor cut off switch to the compressor relay like I have done before.
Yes it is good to run the compressor for a few minutes every month. But once the fog is cleared from the windshield I don't need it to run anymore. Most car always run a small bit of air on the windshield all the time to help prevent more fog from forming. I didn't even notice the problem till a freezing rain hit. I had turned it from defrost to vent and several minutes later noticed the windshield icing up a bit. I miss the older cars where you had a separate slider for each vent location and YOU could choose how much and where you wanted the air delivered.
I keep forgetting we are dumb consumers unable to cope with such matters.

Bob

 

Like others have said Gm like most all americian cars only blow air on the windshield when in defrost mode. I hate putting the defrsot on too A/C lowers gas mileage. Get the vent visors and leave the windows cracked to keep the fog off the windshield. As for ice there is nothing you can do about the but leave defrost on. Good luck