lam5

My 93 sc300 heater works great when the car is cold in the morning, but if i go somewhere and let the car sit for a short time the heat will not turn on. The temp gauge is not at the bottom. I put the fan on high, but it just blows cold air. If i put it on auto, nothing blows. After 10 to 20 minutes, i here a click and the heat will turn on. But with the cold Chicago winter, that is just too long. I've turn the temp **** from cold to hot several times, and sometimes the heat will go on after i turn it back to hot. Could this be the heater valve? Will switching the vacuum lines at this point help to get heat right away during a warm start?

RTIS250

iTrader: (9)

I would check operation of the solinoid on the heater control vavle.. sounds like its sticking.

Nutech

Heater Control Valve maybe bad. They are pretty expansive around $275 in parts. Ask someone in your area to have it check out.