My 1999 SR5 4Runner has decided that even when it's all the way in the cold position to blow hot air through the vents.

Any thoughts on where to start tracking down this problem -anyone had a similar experience?

 

I'm thinking Thermostat.....but I'm no expert.....

 

Mix control thing, it doesnt have the electric climate control does it?

 

If it's the electric climate control, its the thermostat (located under the glove box/ above feet area in the passenger side). I had the same problem, except mine was stuck on cold in the winter.

 

I had this issue about 3 years ago on my tacoma. It has the dial type knob, and it turned out that the cable that runs to the engine compartment had slipped off the "arm" that it is connected to (in the compartment) to control the temp. Try taking a look under the hood.