climate control (heat)- AUTO doesnt work, other settings do?

[HoustinoJillian]

heres the deal- it seems likewhen the car is started and warms up in the AUTO setting , for the duration of the trip it blows very weakly, if you put your hand up to the vent its warm, but doesnt blow hot air int othe car even when the fan is turned all the way up. if i let the car warm up in OFF, and then switch over to panel/floor when its at normal operating temp, it blows strong hot air. any ideas why?

2 possibilities- somehow related to the low coolant sensor thinking i dont have any coolant (soon to be fixed), or the interior temp sensor isnt working? any ideas how to check that, or other possibilities? would running codes help with something like this?

 

[ohfosho]

well depending on what temp you have it set at, that affects the blower motor speed. and if you press the auto button when your car is cold (in the morning), it will turn off the fan, untill the engine is slightly warmed up...then you will notice it come on. i like to keep mine set at 32 deg (celcius), and just adjust the fan speed myself anyway

 

[HoustinoJillian]

i understand how the auto setting works. the problem isnt that i dont know how to work my climate control, its that regardless of fan settings, AFTER the car is properly warmed up, the auto setting still blows no hot air into the car.

 

[Rockledge]

What happens if you switch from AUTO to another mode, does the fan work properly in the other mode?

How about if you switch from AUTO to another mode and then back to AUTO?

 

[laxmax327]

isnt there some sensor for it behind the sho logo on the passenger side. i think that may affect the auto mode. look into that maybe.

 

[HoustinoJillian]

it seems to be that when i switch from auto to a different mode it keeps the problem. i'll verify in the morning on the drive to work.

 

[Rockledge]

Couple of more things to consider. First, try the EATC self-test and see if it kicks back a code:

http://www.shotimes.com/php-bin/mod...e=article&mode=thread&order=0&thold=0&sid=139

Note: the key should be in the ON position when doing the EATC self-test.

Also, there is a "Cold Engine Lockout Switch" (CELO) located on one of the heater hoses, its function is to prevent (limit?) blower motor operation when the motor is cold (coolant temp. below approx. 50°F) and the system is in AUTO. When the engine warms up past that threshold, the CELO allows the blower motor to run when heat is required.

 

[HoustinoJillian]

cool thanks, ill also try that in the morning after i get to work. i'll update tomorrow from the office as to the results.

 

[HoustinoJillian]

alright so on the way in to the office, i started with the climate control completely off until the temp needle was at about the M (normal range). i then turned it on auto, waited 30 seconds or so, nothing. turned up the fan, and i heard an increase in fan noise, but still no increase in heat output. hit the floor/panel button, and heat came pouring out. switched back to AUTO, same problem as before.

Did the EATC self test, returned the code 888 (everything lit up) which should mean that everything is OK. my feeling is that its the ambient in car temp sensor. anyone have other suggestions, and if not, where is this sensor located, IIRC inside the dash behind the SHO logo, is it possible to get to without pulling the dash? and if it were the problem why didnt the EATC test pick it up?

 

[projectSHO89]

Your problem is unlikely to be either the CELO switch or the ambient air temp sensor.

Check for the distribution of air through each of the possible single-outlet settings: panel, floor, or defrost (no combinations). My bet is that the floor setting will not work while the other two will.

When in AUTO mode, heat is routed through the FLOOR and DEF (minimal flow) outlets. You described good airflow when in PANEL-FLOOR but didn't indicate the source of the airflow. I'm guessing it was coming from the panel vents.

My suspicion is one of the vacuum motors is not working correctly due a vacuum line, motor, EATC vontrol head problem.

Steve