No heat
Thread Starter
Pit Crew
Joined: Jun 2016
Posts: 189
Likes: 74
From: Illinois
No heat
Hey guys, I was driving my SC this morning and I had the climate control set to 75. It seemed like the air coming out was cold, so I turned off the AC (though I think that is auto as well?) and turned it up some. Still pretty cold air coming out, so I went all the way, and the fan still only went to 2 bars, and the air was still the same temp coming out. The car was fully warmed up by this point, but even if it wasn't I would assume that the fan would go all out trying to warm the car up. I am not very familiar with these cars yet, and the normal sequence of operation for the climate control.
So first up, was the climate control working the way it should?
Why am I not getting any hot air out of the vents?
I would need to look back through the receipts to see if the heater core was ever changed, but I would assume so being a 1993. If not maybe its plugged? Would I be able to see the valve that allows coolant to go though the heater core so I can see if its actuating? Any help is appreciated guys! The car is a 1993 SC400
Thanks!
Sean
So first up, was the climate control working the way it should?
Why am I not getting any hot air out of the vents?
I would need to look back through the receipts to see if the heater core was ever changed, but I would assume so being a 1993. If not maybe its plugged? Would I be able to see the valve that allows coolant to go though the heater core so I can see if its actuating? Any help is appreciated guys! The car is a 1993 SC400
Thanks!
Sean
No heat would generally mean a bad or bypassed Heater Control Valve (visible in the engine bay on the firewall). However, not being able to increase the blower speed indication suggests that your HVAC unit is bad or the wrong part number for your year. To confirm the part number, you would have to perform mild surgery like if you were doing a stereo install.
Thread Starter
Pit Crew
Joined: Jun 2016
Posts: 189
Likes: 74
From: Illinois
No heat would generally mean a bad or bypassed Heater Control Valve (visible in the engine bay on the firewall). However, not being able to increase the blower speed indication suggests that your HVAC unit is bad or the wrong part number for your year. To confirm the part number, you would have to perform mild surgery like if you were doing a stereo install.
Sean
Thread Starter
Pit Crew
Joined: Jun 2016
Posts: 189
Likes: 74
From: Illinois
No sure about the bars on the control unit, but if your temps from the vents seem to fluctuate, or does not decrease/increase when you turn the ****, it may be the heater control valve on the passenger side firewall starting to go out. When mine was acting oddly, the valve showed signs of coolant weeping from it. Though not guaranteed to be a sure sign of failure, it's a place I would suggest starting with. I believe if you have someone help you adjust the climate control temp while you are looking at the valve in the engine bay, the arm should move corresponding to the **** being adjusted.
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Thread Starter
Pit Crew
Joined: Jun 2016
Posts: 189
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From: Illinois
Yeah, I am less concerned with the fan not going up when I turned it up since I am getting a LXCC soon, I was more just curious. I will have to check the valve when I get a chance and go from there.
Sean
Sean
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How do you know that for sure? Have you inspected both? You've only been a member here for 3-4 months, so I'm assuming you haven't had the car for long. Previous owners have done lots of crazier things.
Thread Starter
Pit Crew
Joined: Jun 2016
Posts: 189
Likes: 74
From: Illinois
Here is an engine bay shot just because. Tell me you wouldn't be surprised to see bypassed heater controls in a car this clean from Chicago.
Sean
See posts 3 & 4 here. It's a quick test you could do. If your heat comes back, then you know either that Vaccuum Switch is bad, or its not getting the signal from it's source to toggle on.
https://www.clublexus.com/forums/per...rol-valve.html
https://www.clublexus.com/forums/per...rol-valve.html
Last edited by Halon; Sep 28, 2016 at 07:04 AM.
This doesn't guarantee anything of course, and I will still inspect these things, but I would be VERY surprised to find anything like that on this car.
That's a far cry from, "I guarantee 100% that nothing is bypassed, and there are no incorrect parts installed." The car does look clean and well maintained, so you likely are correct that the HCV wasn't bypassed by a P.O. But, when you're asking for help, it doesn't make sense to rule out possibilities before even exploring them.
Thread Starter
Pit Crew
Joined: Jun 2016
Posts: 189
Likes: 74
From: Illinois
See posts 3 & 4 here. It's a quick test you could do. If your heat comes back, then you know either that Vaccuum Switch is bad, or its not getting the signal from it's source to toggle on.
https://www.clublexus.com/forums/per...rol-valve.html
https://www.clublexus.com/forums/per...rol-valve.html
Getting back to those warm temps, it only ever got kinda warm. Not sure now if the valve didn't open fully, or if the heater core is clogged. I will investigate more sooner or later, but at least I know the actuator is bad for a start. I will probably change that and see how it goes after I get that in. Ill keep you guys posted.
Sean
Lead Lap
Joined: Nov 2004
Posts: 421
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From: Illinois
So I ended up trying this last week, and it sort of worked. So lets start with the controls since that seemed to throw people off. If I turned it just to max temp, the fan would go to speed 2. However, I found later that if I turned it to defrost it would go full speed. When I bypassed the actuator and got some heat, turning the temp to max would make the fan go full speed. Seems like it wont just blast cold air, it waits until it sees some temp in the heater core (or something) before allowing the fan to ramp up. I kind of had a feeling that was how it worked, and it seemed to be true once I could actually get some warm temps into the system.
Getting back to those warm temps, it only ever got kinda warm. Not sure now if the valve didn't open fully, or if the heater core is clogged. I will investigate more sooner or later, but at least I know the actuator is bad for a start. I will probably change that and see how it goes after I get that in. Ill keep you guys posted.
Sean
Getting back to those warm temps, it only ever got kinda warm. Not sure now if the valve didn't open fully, or if the heater core is clogged. I will investigate more sooner or later, but at least I know the actuator is bad for a start. I will probably change that and see how it goes after I get that in. Ill keep you guys posted.
Sean
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