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HVAC System Delay on Start

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I have recently purchased a 2004 CTT, I haven't driven it much (travelling for work) but I have an issue when I start it up that happens now and then...


The HVAC system will not immediately come on, sometimes it will kick on a minute later, sometimes it will take up to 3 minutes.  Sometimes it sounds like the vents under the dash are opening and closing right after the Cayenne is turned on before air runs thru the ducts.


Is there some sort of relay switch going bad, or some sort of setting on the HVAC controls that needs changed?



Thank you

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When your battery is low on charge the ancillaries won't come on until it is charged back up to a certain level, which it will do after a minute or two of driving.  Either you've got an excessive draw on your battery when your Cayenne is parked or your battery needs replacing or both. Usually it's just the battery.

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Yes, this is a *feature* to protect the electronics.  The HVAC blower will draw enough current to dip the car's voltage and possibly create voltage stability issues with the ECU, etc.


I'd charge the battery now and place it on a trickle charger while away for extended periods (7 days+).

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  • 1 month later...

Thank you for the suggestions.


I had changed the battery a few days after I made this post and everything seemed fine for the most part.


My wife has used this car as a daily driver but she only drives about 4 miles round trip.


Occasionally the automatic locks won't work, and the HVAC system is delayed on start up like before.  It isn't happeneing as frequently but it's still happening on days it's ran and turned on and off several times.


I am guessing I have an excessive draw somewhere, but any last suggestions before I take it to a mechanic?


I still need to purchase a trickle charger, but am I going to need to put in on a trickle everyday?  Seems excessive.

Edited by enoteche
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