Darylls

You are correct about the control valve, and that was a good first step. Sorry to hear that wasn't it. My next step would be either the core is clogged of the blend door is not functioning. The climate control does have a diagnostic mode, have you looked to see if there are any codes? Do you have a manual that describes how to access the diag?

To place the system in diag, PRESS AND HOLD THE AUTO SWITCH, WHILE ALSO PRESSING THE FRONT/REAR SWITCH, with the other hand turn the ignition switch on. All of the indicator lights should flash on/off 4 times, then it will start flaching the code. To exit the diag mode, press the off button.

I have a list of the codes, but the last time I tried to upload to this site it did not go very well. So if you would like a copy send me a PM, and I can email you a copy

I dont have the manual but i will try doing the steps you said tommorrow and see what codes there are. I am going to try and disconnect the control valve and just bypass it see if that works then i know its that the valve is stuck. I fnot do you know how to unclog the heater core and where is the blend door located, when i push the buttons to control the air flow from vent,floor or defrost i here it working. To answer your question it wasnt to hard to get to the tstat you need a shallow 12 mm socket with a short exstention and need to loosen the alternator adjustment bolt so you can get the serpintine belt loose to reach the bolt on the tstat.

I tried doing the diag on the climate control and it did nothing i hel the auto sitch and the front and rear defrost switches and turned the key to on and nothing happened.I am going to try and bypass the control valve by the firewall and see what happens

You are correct about the control valve, and that was a good first step. Sorry to hear that wasn't it. My next step would be either the core is clogged of the blend door is not functioning. The climate control does have a diagnostic mode, have you looked to see if there are any codes? Do you have a manual that describes how to access the diag?

To place the system in diag, PRESS AND HOLD THE AUTO SWITCH, WHILE ALSO PRESSING THE FRONT/REAR SWITCH, with the other hand turn the ignition switch on. All of the indicator lights should flash on/off 4 times, then it will start flaching the code. To exit the diag mode, press the off button.

I have a list of the codes, but the last time I tried to upload to this site it did not go very well. So if you would like a copy send me a PM, and I can email you a copy

I dont have the manual but i will try doing the steps you said tommorrow and see what codes there are. I am going to try and disconnect the control valve and just bypass it see if that works then i know its that the valve is stuck. I fnot do you know how to unclog the heater core and where is the blend door located, when i push the buttons to control the air flow from vent,floor or defrost i here it working. To answer your question it wasnt to hard to get to the tstat you need a shallow 12 mm socket with a short exstention and need to loosen the alternator adjustment bolt so you can get the serpintine belt loose to reach the bolt on the tstat.

Hi I just purchased a 93 es300 and it had no heat. I went to replace the thermostat and found out there wasnt one in so i bought a new one put it in still NO Heat its 20 degrees out here and its hard to drive a car with 2 young kids with no heat Help PLEASE!!! I looked today and noticed on the driver side of the firewall there is a control valve with a cable attached thst looks like it goes to the heater core the cable was disconnected so i switched it by hand and still no heat.Dont know what else to do PLEASE HELP THANKS