peterp

My wife had an accident with the Q5. It was somewhat minor but did require the radiator and a lot of parts in the front-end to be replaced. The Audi-authorized repair facility did a great job, but it seems like the climate control no longer works right. It has been sub-freezing outside, but the heater fans do not come on at max level even when I have temperature set to "HI" and the car is warmed up.

I have seen this behavior on rare occasion before the accident, but now it seems like it is a constant issue. Does anybody know if there are sensors at the front of the car that would affect climate control behavior? Also, has anybody else experienced this issue?

ex-quattro PETE

The outside temperature sensor is somewhere out there, and if it is not working correctly, it would affect the functioning of climate control to some extent.

However, you say that the system is not working properly even when you set it to "HI", so that outside temp sensor is probably not the problem here, or at least not the only problem.

Is your outside temp reading accurate?

There are also temp sensors inside the cabin and sensors monitoring how much sun is directly hitting the cabin. If any of these are acting up, it might potentially affect your climate control system.

Have you had the car connected to a diagnostic tool to see if any error codes are stored in the ECU?

peterp

Thanks for your response. I should clarify what I mean by "HI". I mean that I have the climate control in "Auto" mode and I am setting the driver and passenger temperature to "HI". With that setting, I expect the fans to be off while the car engine/coolant is cold and for the fans to run on high for maximum heating when it is fully warmed up. What I am seeing is that the fan does come on, but it runs at a very low level while in "Auto" mode with temp setting on HI and the cabin temperature still very cold.

Yes, the outside temperature is reading exactly correctly and it is reading in the 20's when this occurs.

I have not connected to to any diagnostic tools. I'm trying to figure out whether I need to bring it to the repair center or the Audi dealer (or if it's some stupid operator error setting on my side!).

ex-quattro PETE

Yup, that is how I understood it the first time you explained it.

When you increase the climate temp all the way up to "Hi", the system should ignore all the temperature sensors and just start blowing hot air at full blast, just as long as the engine is fully warmed up. If it's not doing it, then something is not right.

Redd

peterp-
I have seen AC malfunction on another car after a hard hit. Turned out the impact was enough to rotate a loose turnpot in an AC control module. Who'd think...But yes, an impact can telegraph through odd parts of a car, unseating them, rotating them, fracturing them.
Too many parts in a climate control system. Unless you can capture an error code, time to let the high-priced witchdoctors auger the entrails in search of clues.

peterp

Thanks for the info and sorry for the delayed response -- I missed it when you first posted and then thought there were no more updates to the thread. What's weird is that it does work -- when set to HI, the heater does come on, just with fan speed very low.

Is there a way for me to see error codes without diagnostic equipment?

Redd

"Is there a way for me to see error codes without diagnostic equipment? "
No. But many chains and shops will pull the diagnostic codes for free.

Or, you can but an OBD-II port code reader,
http://smile.amazon.com/gp/product/B...?ie=UTF8&psc=1

like this one from BFAX for $24 shipped. Uses a BT phone as the display, so you can leave it plugged in (they shut off when the car is off) and just check your phone if you want to read something. Either with free apps, or something like Carista.

hilld

Also there could be an air pocket in the heater core if the cooling system was opened up. This could cause a lack of heat.

JaXeN

In my experience, the outside temp sensor for the display on the dash and the outside temp sensor for the climate control are completely independent of each other.

Learned this the hard way with my last Audi when I had symptoms similar to yours.
In my case though, setting the CC controls to MIN or MAX would give me cold or hot air respectively.... Anything in-between would yield results similar to what you're experiencing.

With the cable and software, you should be able to determine fairly quickly what's amiss with your system.

peterp

Thanks for all the feedback. I spoke to the body shop and the owner wants to take a look at it. He suggested it might be an air pocket (as mentioned here) or a sensor screwing things up.

The OBD2 smartphone reader is pretty cool. The one linked is for Android, so I'll need to find one for iPhone 6 (there are plenty on Amazon, need to find which is best).

Thanks for all the help,
Peter