benbac

The A/C light is blinking and my A/C is blowing out hot air, the system was flushed and recharged the other year and the pressure is still good and doesn't seem to be leaking. The car sat for a while, batteries died and were replaced, wondering if A/C was deactivated and needs to be reset before continuing down this rabbit hole.

Does anyone know what the A/C reset procedure is (without an SDS)?

benbac

I called up the local dealership and the service adviser informed me there is no reset procedure and that it needs to be scanned / re-coded, that it is common for codes to "drop" or "reset" when a car's battery is disconnected or dies.

I saw another post saying to try disconnecting the battery for five minutes, i'm assuming to disconnect the main (in the trunk) as opposed to the convenience battery. I will try this unless someone here tells me otherwise, before bringing it to someone with an SDS.

kustom2k1

The odds are low that the battery is the cause. Most likely AC issue.

benbac

So I couldn't wait for the dealer in my area to schedule me to do a scan and charge me for it (days were getting above 90). so I found a shop that had some non MB SDS tool able to scan my car; a ton of fault codes appeared, including some A/C codes (looks like the dead battery/battery swap may have reset some things). They cleared/reset them and only a handful remained, in the end it did get the A/C light to stop blinking and A/C compressor to start running.

But like most of you assumed it was still an A/C issue (hot air was still blowing), apparently my car was really low in refrigerant. A re-charge did the trick. They did the standard vacuum, leak test and recharge. Checked the pressure (brought it down to zero), added some oil to lubricate the system, dye to help identify any leaks in case there is one in the future, and added the refrigerant (not sure of the exact order but that's the gist of it) ... and voila, I have cold air!

I originally assumed that if the system is able to maintain it's vacuum pressure that it shouldn't have a leak, and in a closed system (like a refrigerator) it shouldn't. But apparently car a/c systems can leak!

This article brought that to light: http://autotechac.com/ac-facts-and-myths/
And considering my car sat for 2 years, i can understand why it was low now, and hopefully now with the added oil into the system and the car running and circulating, it'll help lubricate the system and reduce any leakage.