Darylls Posted December 21, 2008 Share Posted December 21, 2008 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 Quote Link to comment Share on other sites More sharing options...
George_Jetson Posted December 21, 2008 Share Posted December 21, 2008 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 Quote Link to comment Share on other sites More sharing options...
George_Jetson Posted December 21, 2008 Share Posted December 21, 2008 Ps. How hard was it to replace the thermostat? Mine appears to be opening a little to soon, but I've been putting it off for other projects. It looks like it could be a little bit of a pain to access down there where they put it. Quote Link to comment Share on other sites More sharing options...
Darylls Posted December 21, 2008 Author Share Posted December 21, 2008 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. Quote Link to comment Share on other sites More sharing options...
Darylls Posted December 21, 2008 Author Share Posted December 21, 2008 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 Quote Link to comment Share on other sites More sharing options...
George_Jetson Posted December 21, 2008 Share Posted December 21, 2008 Since you allready prepared to disconnect the valve, it you remove the other hose to the heater core, you could hook a hose core and run water thru it. If it has poor flow then you core is clogged. I was looking in Alldata, they have some good pictures on this. It would appear that you may be able to change the heater core without pulling the dash. If that is the case, I would search ebay and find a new replacement heater core. You would be surprised a some of the deals you can find, couple years back I replaced the evaportator on my truck, new core was less than $50 with shipping. I was looking further into alldata, it appears that there is not a blend door in the lexus (I work mainly on dodge). It does indicate that the heater valve is closed when the cable is extended from the housing. Alldata indicates that the book hours for replacing the core is 1.8. Of course this is for someone that is experienced with this procedure, count on it taking longer. Quote Link to comment Share on other sites More sharing options...
George_Jetson Posted December 22, 2008 Share Posted December 22, 2008 I re-read alldata, I made a mistake on how to place it into diag, Hold the auto button, and the recirc/outside air button down. Then turn on the key, I tried this on my 92 and it does work. Quote Link to comment Share on other sites More sharing options...
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