No Heat Unless Set to 85

[mkiii222]

I recently replaced my heater core.

When I have the heater control (89+ control, 87 car) set at anything other than 85 I get cool air. Set it to 85 and it's HOT.

I would imagine that this is caused by the blend door not opening. Did I miss a plug somewhere that allows it to open the door partially?

 

[IBoughtASupra]

So if you set it in high with the temp at 75, you still get cold air?

I would assume your blend door is not opening at the lower levels to allow the warm air through. Do the other blower settings work, the ones that direct the air where you want it?

 

[Nick M]

You want to make sure the heater valve for the coolant is opening when it is supposed to open. Also, when the coolant is cold, the control unit will not open the heater valve.

 

[Poodles]

See that little gizmo under the wiper blade? If yours looks like that, that's your problem. It's the light sensor for the climate control, and it's supposed to have a smoked plastic cover over it. Without the cover it thinks the sun is really intense, so it compensates by blowing cold. 65 and 85 bypass all the automatic settings though, with full A/C or full heat respectively.

 

[SideWinderGX]

Mine's missing too. Can't find a part # for it in the TSRM though, anyone happen to know where it is/what it is?

 

[Poodles]

88625-20140

It's the same for all years, and it's cheap. It's the entire sensor.

 

[mkiii222]

Would it act the same if the sensor were just not plugged in?

I ask because it worked last winter before I looped the heater lines and now after removing/replacing the dash it doesn't work. All other CC functions are working properly.

I'll have a chance to properly look at it Sunday afternoon.

Is the part # in the part # sticky on the main page? If not it should be.

 

[RazoE]

Had this same issue

http://www.supramania.com/forums/showthread.php?113950-Heater-only-works-when-set-to-85*

 

[Poodles]

Would it act the same if the sensor were just not plugged in?

I ask because it worked last winter before I looped the heater lines and now after removing/replacing the dash it doesn't work. All other CC functions are working properly.

I'll have a chance to properly look at it Sunday afternoon.

Is the part # in the part # sticky on the main page? If not it should be.

No idea. The quick test is to put your hand over it and see if it blows warm again (mine did).

 

[mkiii222]

Thought I'd finally close this one up. We all hate threads with no conclusions.

So after sniffing around the passenger side looking for something to be unplugged it turns out that FL was just too hot.

I spent a couple hours one day just under there poking around not finding anything left unplugged. The past week or so it's been about 60 in the AM. The heat comes on just fine.

Conclusion: Make sure it's under 80 outside when trying to test the heater controls.