Gs300 Climate Control Problem

[94GS300Fan]

I have a 1994 GS300 that I purchased new. Up until now the car gas run flawlessly, but now with the weather turning colder I noticed that the heater doesn't work. The A/C seems to be fully operational but even when the A/C is turned off I only get cold air out of the ducts. Are the climate control servos easy to get to on this car? There have been some similiar posts but they are for models with separate heater control for driver and passenger. My car has only one temperature control.

[silverbullitt]

The last time I had an issue like this I thoroughly drained & flushed my coolant system & put in a new thermostat. The heat returned afterwards. It also can be your heater core behind the dash

[94GS300Fan]

The engine temperature is normal so I don't think I have a thermostat problem. But, I should check if warm water is getting to the heater core.

have you or anyone else found good drawings as to where the various components are? ALLDATA has some good diagrams but no location info.

[94GS300Fan]

I found my problem. The cable controlling the water valve on the firewall jumped out of the arm and the valve was shut off. I switched the valve to "ON" manually and the climate control seems to be working normally now. I'll have to investigate further when I have some time, but for the winter I'm OK for now.

[94GS300Fan]

By the way-

While trying to diagnose this problem, i found out that the climate control microprocessor has a diagnotic mode that cycles the system through all its various modes and verifies that the doors and acuators are operating properly. You have to press a number of buttons simultaneously to get the climate control in the diagnostic mode. It was helpful in troubleshooting my problem.