Cabin heater blows hot air only

[Darek]

Hi, I have a problem that cabin heater blows hot air at any gauge position, like this:

- 60F - cold air

- 61F - 90F - hot air (the same "hot level")

 

When I turn temperature gauge to be warmer or cooler then it reacts correctly increasing or decreasing blower motor speed but the temperature just stays hot.

 

I did self diagnosis procedure from HA-58 and only issue I found was that in step 5 there should be '5' displayed only but I have '51' displayed. This code is not explained in the manual. Step 5 is responsible for checking temperature sensors: inside, outside, intake. It looks that inside and outside temperatures were correct, I don't know it intake temperature is good or not (it was 50F while outside was 6F and inside 60F).

 

I have LE version with automatic AC. The behaviour is the same in AUTO or ECON mode.

 

Can you guide me how to fix it?

[Darek]

I forgot to write that I have error code P1491 - Vacuum cut valve bypass valve.

[jyeager]

I'm not familiar with 'econ', but I know 'auto'. (model year differences I guess)

 

Mine has OFF/AUTO/LOW/MED/FAST.

Temperature control is only automatic in 'AUTO' mode. If I were to select low/med/fast and the temperature control didn't work, then I wouldn't be looking at sensors as the problem. It would be a simple matter of the air mix flapper not working.

 

I don't think you should be looking at a sensor problem unless you only see this behavior when in an 'auto' mode (not sure if 'econ' is auto or manual).

 

I'm guessing your trouble code is probably not related.

[Darek]

AUTO is using air condition and ECON is not, but both should adjust temperature automatically.

Can you give me some directions how to check the air mix flapper?