Ac Blowing Heat And Air At Same Time

[Lexmachine]

:( My 1993 LS400 started blowing hot and cold air at the same time. When the car is sitting idle, all vents blow cold air, however as soon as I accelerate from a stop, the driver and 2 middle vents start blowing heat and the passenger vent will still blow cold air at the same time. When I accelerate from a stop I can hear a door or (maybe blend door) of some kind from under the passenger dash either open or close, this is when the air stops and the heat starts blowing while the thermo is set to max cold. Can anyone tell me what would cause this.

RBrown86271@aol.com

Thanks Ron

[90LS400Lexus]

Thats peculiar. All I can guess is that the HVAC control panel is one the fritz.

[Lexmachine]

Thats peculiar. All I can guess is that the HVAC control panel is one the fritz.

That was my first thought because my original control panel stopped lighting up but it would still work. I found a Lexus supplier on Ebay and got another for a pretty good price, however i still have the same problem. Someone told me the servo motor was gone but I haven't been able to find any information on what exactly that is. The driver, center vents are blowing heat but the passenger vent is ice cold. There is something in the center dash thats loose because whenever I accelerate from a stop I can hear it then the heat starts. I was also told that was a blend door to which I can't find any info on that either. Do you know of any sites that will show me how to remove the dash, from what I seen from the center area I think the dash will have to come out.

[Lexmachine]

Thats peculiar. All I can guess is that the HVAC control panel is one the fritz.

That was my first thought because my original control panel stopped lighting up but it would still work. I found a Lexus supplier on Ebay and got another for a pretty good price, however i still have the same problem. Someone told me the servo motor was gone but I haven't been able to find any information on what exactly that is. The driver, center vents are blowing heat but the passenger vent is ice cold. There is something in the center dash thats loose because whenever I accelerate from a stop I can hear it then the heat starts. I was also told that was a blend door to which I can't find any info on that either. Do you know of any sites that will show me how to remove the dash, from what I seen from the center area I think the dash will have to come out.

I thought you might be interested in this question on JustAnswer:

http://www.justanswer.com/questions/220vp-...ted-blowing-hot

Regards,

RBrown86271 :P

[steve2006]

This may help you with the layout of the ducting ( section 20 onwards covers the system)

http://www.toyodiy.com/parts/g_U_1993_LEXU...L-AEPGKA_4.html

If you have something loose in there it may be one of the control flaps.

[davegrif]

Hi,

This might help you.

http://www.lexls.com/tutorials/air/accodes.html

You should see what the problem is using the codes. It helped me.

Dave G

[Lexmachine]

This may help you with the layout of the ducting ( section 20 onwards covers the system)

http://www.toyodiy.com/parts/g_U_1993_LEXU...L-AEPGKA_4.html

If you have something loose in there it may be one of the control flaps.

Thanks for the information I'm sure this will be helpful. I'm going to start tomorrow on tearing it down and just take my time, I'll keep the site posted on how I come out. I do think it's one of the flaps.

[Lexmachine]

Hi,

This might help you.

http://www.lexls.com/tutorials/air/accodes.html

You should see what the problem is using the codes. It helped me.

Dave G

That was one of the first thing I checked. No codes, it blows perfect as long as the car is not moving.

[Lexmachine]

:D Ok problem solved the linkage to the driver side servo motor was broken, so the vent door was not closing, also the screw in the water control valve was loose causing the valve not to fully close, so water was still coming through which was giving me heat on the driver side. it was a very tedious job but the overall result is I COLD AIR again. Thanks to everyone for your help.

Lexmanic