HVAC problem: can't change temperature, not heating

[kino]

Hi,

 

I am new to this forum so please forgive me if I missed the topic or if this has been discussed before.

 

The HVAC of my 1994 Legacy Brighton has given up working properly. The display still works fine, I can change the mode, fan level, A/C, switch to manual and defrost without problems. However, I can't change the temperature anymore - it is stuck at 18'C. It also only blows cold air although it's actually colder than 18'C which means it isnt heating and it's bloody chilly in the car.

 

Would be great if someone could point out where the problem may be. Hopefully it is simple enough for me to solve.

 

Thanks!!

[johnegg]

i'm not familiar with the 90 - 94 set up so this may not apply, but for the 95 - 99 cars...

 

the hot coolant from the radiator is always running through the heater under / inside the dash.

when you turn up the heat, a door moves and directs the air flow across the element heating it up.

 

so the difference between heat and no heat is an open door and the direction of air flow.

 

there is a cable that runs from the heater control down to the ''door''.

the door is located on the passenger side floor up under the dash near the center console.

as far forward as you can get.

the door is white.

 

if the cable brakes, or comes loose from the anchor point it will not redirect the air flow.

you can probably move the door with your fingers.

and you can check the lower cable connection.

the black cable sleeve snaps into the bracket, and then

a small c-clip fits into a slop , clicks around the cable sleeve and locks it in place.

the wire cable end fits into a hole on the door.

 

the upper end of the cable is connected to the control in the same way. but you have to pull the unit to see if it is connected.

 

i would check the lower end first.

 

the little c-clip is a real pain to get in place, especially for a guy with old eyes.

but i have 2 cars running with out them on the lower end with no issues.

make sure the heater control up top is in the correct position when snapping the cable sleeve in place down below.

if one is in the cold position and one is in the halfway position you will only get half of the travel distance , and half of the heat.

 

good luck.

[Zues Marine]

using context clues such as 'Celsius' and 'bloody'

 

imma guess you have a digital HVAC?

[kino]

Thanks for the quick answers. I'm not quite sure what you are referring to, johnegg.

 

It is a digital unit indeed, sorry for not pointing this out. It is the same as the one here: http://www.ebay.com/itm/JDM-SUBARU-LEGACY-BG-BD-CLIMATE-CONTROL-WITH-TRIM-AIR-VENT-FACTORY-OEM-/261259611003?vxp=mtr

 

When I'm saying it is stuck at 18' Celsius, I mean the display shows this temperature setup and the up/down keys on the left don't change that setup anymore as they used to. Simply spoken, it seems as if these up/down keys are not working anymore.

 

But if it was that simple, then why does it not at least heat until reaching 18'C? I had it usually set to about 25'C and it was heating nicely until that.

[Zues Marine]

Check out UKlegacy.com

 

They know a lot more about cars from outside the US specs

[kino]

Just an update: It turned out that the 'down' key was stuck somehow. Today it just worked again but then when pressing the down key only once, it would run all the way down to 18C and get stuck there again. Looks like the key has a little fault, I will keep watching it.

 

Still dont understand though why it doesnt heat to 18C when it is set to that temperature. Seems like at this setting it just cools no stop.

 

Cheers

[Zues Marine]

Check out UKlegacy.com

 

They know a lot more about cars from outside the US specs