No A/C or Heat CCU has already been repaired by Brian K

[S2G-Unit]

Last year, I had the AC refilled in my car because the AC wasn't cold. I didn't drive the car much at the end of last year & now, this year I've noticed there is no AC or heat. My CCU was repaired by [MENTION=7588]Briank[/MENTION] back in 2012 I believe. The fan blows at all of the different speeds & isn't only stuck on high. When the AC is on, the air pressure from the vents is normal & strong. However, even in the heat today if I try putting on the heat, there is absolutely no air coming through the vents.


My car will have the WP/TB & thermostat replaced next week. Could the thermostat have anything to do with it?


I wasn't able to do the CCU self test earlier but I will try it again tonight to see if any errors come up.


**edit**
WP/TB, thermostat was changed last week, along with an AC refill & all seems to be ok so far.

 

[Briank]

The fan will not run when the coolant is cold.

 

[Old Guy]

Your current problem is a little unclear. You said:

The fan blows at all of the different speeds & isn't only stuck on high. When the AC is on, the air pressure from the vents is normal & strong.

Is that the way it was last year or is that the way it is right now (in which case I am doubly confused)? Currently, can you hear the fan running; but, you are getting no air flow? If so, you might have a problem with the vent door / recirc door. I think if you run through the CCU self test it will flag a problem with one of the air control motors. If not, refer to the service manual for the detailed trouble shooting procedure.

Currently, if you are not getting any air flow because the fan isn't running, is the CCU in auto? I admit that other than the occasional tweak of fan speed or temperature, I don't really pay attention to how my HVAC is set. However, even if the engine is cold, if the controls are in manual mode I think you can force the unit into AC operation. In manual mode if you hear the compressor engage and the interior blower motor is running then you have to have a vent control problem of some kind.

 

[S2G-Unit]

Your current problem is a little unclear. You said:



Is that the way it was last year or is that the way it is right now (in which case I am doubly confused)? Currently, can you hear the fan running; but, you are getting no air flow? If so, you might have a problem with the vent door / recirc door. I think if you run through the CCU self test it will flag a problem with one of the air control motors. If not, refer to the service manual for the detailed trouble shooting procedure.

Currently, if you are not getting any air flow because the fan isn't running, is the CCU in auto? I admit that other than the occasional tweak of fan speed or temperature, I don't really pay attention to how my HVAC is set. However, even if the engine is cold, if the controls are in manual mode I think you can force the unit into AC operation. In manual mode if you hear the compressor engage and the interior blower motor is running then you have to have a vent control problem of some kind.

Sorry, with the AC on, the fan speed is variable and the amount of air coming out does change. However, if I turn on the heat, there is absolutely no air coming out at all.

 

[Old Guy]

If you have the CCU in heat in full auto, my recollection is as Brian K noted, nothing is going to happen until the engine coolant temperature has risen to an appropriate level. If your engine temperature is not coming up to operating level because of a faulty thermostat then that would prevent operation in the heat mode. If your dash gauge indicates that the engine is coming up to operating temperature then you should get operation in heat mode. Note that the CCU has an engine coolant temperature sensor. I believe that this sensor is completely separate from the coolant sensor for the dash gauge or the ECU; but, I don't have my SM handy so I cannot confirm that. If that sensor has gone bad / out of range then it could block heat operation even if the engine is hot. I think that complete failure of that sensor is detected by the self check mode; but, it is possible that if it is slightly out of range then the self check mode may not flag a problem. Best to consult the service manual for the trouble shooting procedure.

I think if you take the CCU out of full auto mode you should be able to force blower operation in heat mode even if the engine temperature is not up to operating. However, I am not 100% sure about that. I read the owners manual 9 years ago, fiddled with the controls then and have pretty much left it alone since other than having to reset everything when I reconnect the battery every spring.

 

[S2G-Unit]

If you have the CCU in heat in full auto, my recollection is as Brian K noted, nothing is going to happen until the engine coolant temperature has risen to an appropriate level. If your engine temperature is not coming up to operating level because of a faulty thermostat then that would prevent operation in the heat mode. If your dash gauge indicates that the engine is coming up to operating temperature then you should get operation in heat mode. Note that the CCU has an engine coolant temperature sensor. I believe that this sensor is completely separate from the coolant sensor for the dash gauge or the ECU; but, I don't have my SM handy so I cannot confirm that. If that sensor has gone bad / out of range then it could block heat operation even if the engine is hot. I think that complete failure of that sensor is detected by the self check mode; but, it is possible that if it is slightly out of range then the self check mode may not flag a problem. Best to consult the service manual for the trouble shooting procedure.

I think if you take the CCU out of full auto mode you should be able to force blower operation in heat mode even if the engine temperature is not up to operating. However, I am not 100% sure about that. I read the owners manual 9 years ago, fiddled with the controls then and have pretty much left it alone since other than having to reset everything when I reconnect the battery every spring.

The temperature gauge seems to be normal. However, if I recall in the fall there were a few times where the temp gauge would only go up 1/4 way .
I'll re try the CCU self test mode. I couldn't get it to work last time.