Sounds like a Heater VSV Failure:
http://www.rclambert.com/supra/vsv.htm
and
http://www.ddmcse.com/turbo/heatervs.html
and here: http://www.toyotanation.com/forum/showthread.php?t=175907&highlight=heater+vsv
http://www.rclambert.com/supra/vsv.htm
and
http://www.ddmcse.com/turbo/heatervs.html
and here: http://www.toyotanation.com/forum/showthread.php?t=175907&highlight=heater+vsv