Please help, not getting heat!! 93 LS400
11-09-13, 02:11 PM
#31
Had the same heater issue. The temp gauge on the dash was working. Thermostat seemed fine as hoses hot. Servo motor working fine. Cable not bent. Looked at the coolant reservoir and saw it was empty......hmmmm? Put a gallon of 50/50 coolant and heat started working again. Great thread and very helpful. Sometimes its just routine maintenance.
11-19-19, 07:26 PM
#32
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1999 LS400 Heater Control Valve Cable Broke
Sorry to post to such an old thread but seems like this is where it should go. I am new to the forum so please bear with me.
My wife's 1999 LS400 (GREAT car, BTW!) got to where at idle, a/c just blowing cold air. As RPM increased to over 1500 or so, heat gradually got warmer and when temp set at over 80 deg (HOT) the air stayed pretty hot. However, at idle same deal - cold air.
Inspecting the heater water control valve, and running the A/C diagnostics, the HCV did not move. I tried moving it by hand and it would move freely. I suspected a bad HCV servo So using info from this thread and others, I was able to remove the stuff under the dash and get to the HCV servo. I watched it as I ran thru the diagnostics. Noticed that the servo worked as it should, but there was no cable attached to the servo! Removed screws to servo and it fell right off! Problem was the HCV CABLE was broken right where it goes up in the sleeve at the servo. Searched floorboard under carpet and found the cable end that had broken off. It was bent at over a 90 degree angle. So I assume the cable popped off the servo, got caught in the arm, and bent and broke.
Checked with Lexus dealer and the parts guy was astounded that he could not find a parts listing for the HCV cable. He told me he would research the problem and call me back. Shortly thereafter he called and said in 1998 Lexus changed the design of the HVAC system and that cable was changed to a "non-serviceable item," meaning you had to buy that entire box with all the servos on it to get the cable! (like several hundred $$$ to get a $15 cable!) Even worse, all those items were now obsolete and unattainable by the dealer. Even the cables for the '97 and earlier were no longer available! Dealer told me only option was to find a cable at junkyard.
My problem, after hours and days of searching, I have yet to find a source for even a used cable. Junk yard folks admit that when they take those servo motors off they always cut the cables because it is hard to get them out of the clip/clamp at the servo and is a waste of time for them.
So my questions to the forum are:
1. Does anyone have that cable on a junk car that I could buy from them
2. Has anyone else had this problem an somehow fabricated a workable cable and how they did it.
Thanks for any help!
My wife's 1999 LS400 (GREAT car, BTW!) got to where at idle, a/c just blowing cold air. As RPM increased to over 1500 or so, heat gradually got warmer and when temp set at over 80 deg (HOT) the air stayed pretty hot. However, at idle same deal - cold air.
Inspecting the heater water control valve, and running the A/C diagnostics, the HCV did not move. I tried moving it by hand and it would move freely. I suspected a bad HCV servo So using info from this thread and others, I was able to remove the stuff under the dash and get to the HCV servo. I watched it as I ran thru the diagnostics. Noticed that the servo worked as it should, but there was no cable attached to the servo! Removed screws to servo and it fell right off! Problem was the HCV CABLE was broken right where it goes up in the sleeve at the servo. Searched floorboard under carpet and found the cable end that had broken off. It was bent at over a 90 degree angle. So I assume the cable popped off the servo, got caught in the arm, and bent and broke.
Checked with Lexus dealer and the parts guy was astounded that he could not find a parts listing for the HCV cable. He told me he would research the problem and call me back. Shortly thereafter he called and said in 1998 Lexus changed the design of the HVAC system and that cable was changed to a "non-serviceable item," meaning you had to buy that entire box with all the servos on it to get the cable! (like several hundred $$$ to get a $15 cable!) Even worse, all those items were now obsolete and unattainable by the dealer. Even the cables for the '97 and earlier were no longer available! Dealer told me only option was to find a cable at junkyard.
My problem, after hours and days of searching, I have yet to find a source for even a used cable. Junk yard folks admit that when they take those servo motors off they always cut the cables because it is hard to get them out of the clip/clamp at the servo and is a waste of time for them.
So my questions to the forum are:
1. Does anyone have that cable on a junk car that I could buy from them
2. Has anyone else had this problem an somehow fabricated a workable cable and how they did it.
Thanks for any help!
11-21-19, 06:40 PM
#34
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UPDATE: HCV cable broken - 1999 SL400
Successful in finding a local salvage yard with exact car and parts I needed. Have now replaced the cable and servo motor and heat seems to be working as it should. Here's method I used to replace those components:
1. Unbolted and laid back driver seat to provide working clearance.
2. Stuck long piece of copper wire thru cable hole in firewall beginning in firewall area. Attached the end of copper wire protruding into lower dash area to one end of the control cable
3. Fished the control cable thru the firewall but left hanging until attached to servo motor.
4. Attached servo motor to electrical connector while hanging loose, and ran A/C diagnostics to see position of servo motor arm when water valve would be shut
5. Attached cable to servo motor arm, and using 1/4" ratchet and a 7mm bit attached the servo motor using the 2 phillips screws.
6. With servo motor in the HCV CLOSED position, moved arm on HCV to match cable, attached the cable to the HCV arm, and closed the cable clamp on HCV.
7. Battery had run down by now due to cabin lights on, etc, so charged battery, cranked engine and ran about 3000 RPM until water temp normal, and tested operation of the heating system. VERY GOOD!
8. Next step is to install front and rear heated oxygen sensors, since the connections for the #2 sensors' pigtails connect at the side of the hump under carpet. Gas mileage is only abt 18MPG so hope replacing the front sensors will fix that problem. Also have a PO430 "Catalyst inefficiency..." code so rear sensors will hopefully get that. If not, will insert a spark plug fouler at respective sensor to resolve issue short term.
9, To Be Done: Replace ductwork and lower dash components on driver side and wrap things up.
Hopefully this info will be helpful to some others out there with similar problems. Apologize for not attaching any photos but previous posts by others have basically covered most of the procedures and I just don't have time right now to figure out how to post pics on this forum
1. Unbolted and laid back driver seat to provide working clearance.
2. Stuck long piece of copper wire thru cable hole in firewall beginning in firewall area. Attached the end of copper wire protruding into lower dash area to one end of the control cable
3. Fished the control cable thru the firewall but left hanging until attached to servo motor.
4. Attached servo motor to electrical connector while hanging loose, and ran A/C diagnostics to see position of servo motor arm when water valve would be shut
5. Attached cable to servo motor arm, and using 1/4" ratchet and a 7mm bit attached the servo motor using the 2 phillips screws.
6. With servo motor in the HCV CLOSED position, moved arm on HCV to match cable, attached the cable to the HCV arm, and closed the cable clamp on HCV.
7. Battery had run down by now due to cabin lights on, etc, so charged battery, cranked engine and ran about 3000 RPM until water temp normal, and tested operation of the heating system. VERY GOOD!
8. Next step is to install front and rear heated oxygen sensors, since the connections for the #2 sensors' pigtails connect at the side of the hump under carpet. Gas mileage is only abt 18MPG so hope replacing the front sensors will fix that problem. Also have a PO430 "Catalyst inefficiency..." code so rear sensors will hopefully get that. If not, will insert a spark plug fouler at respective sensor to resolve issue short term.
9, To Be Done: Replace ductwork and lower dash components on driver side and wrap things up.
Hopefully this info will be helpful to some others out there with similar problems. Apologize for not attaching any photos but previous posts by others have basically covered most of the procedures and I just don't have time right now to figure out how to post pics on this forum
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