Heated Windshield Fluid Mod/T.B. Coolant Bypass

Have always wanted heated windshield fluid to help break up ice on cold mornings.  Always was thinking of a way to rig up an electrical heater, but the other day had a crazy idea. 

What I am thinking of doing is running engine coolant through the wiper fluid tank.  So get a foot or 2 of 1/4 bras pipe.  Drill 2 holes through the tank, and then seal them up around the pipe with epoxy.  I figured the best place to get coolant would be from the outlet of the throttle body, and I could just install a valve before the T.B. then in the summer months close it to keep the T.B. and the wiper fluid cool.

My 2 questions are:

Where does the coolant go after the T.B.  would it hurt anything to "shut it off" during the summer months?  Meaning if I close the valve no coolant will be flowing and will that hurt anything downstream?

Also is that line coming from the water pump before the thermostat?  So will I get warm coolant before the thermostat opens?  or would I have to wait until the engine warms up?

Thanks again for the info,  anyone else done something like this?

I guess i should say this is on a 2002 5.3l

Wouldn't it be easier to modify a heater and install that in your washer fluid tank?

Couldn't you make a fish tank heater or something like that work?  There must be some type of 12 volt heater in the temperature range you're looking for.

I think that would be safer than messing with your Av's cooling system

Or you could get the factory heated washer fluid system from an 07-09 and install that.

Or do nothing and add washer fluid anti-freeze to bottle in winter...

Are the heated washer fluids prone to cracking windshields in places with pretty cold weather? I would think that blasting an extremely cold windshield with 140 deg F fluid could crack the windshield.