HVAC died today

[Electricfan]

Wow, I've never been branded a Tesla fan boy before... you really have never read any of my past posts, have you?

I don't defend Tesla, I defend common sense and logic. If you had seen some of my past posts you'll know for sure that I definitely do not defend Tesla and do not condone fanboy-ism. When they're wrong they're wrong, just like anyone else. I don't give them passes.

Fact is that there are not "hundreds of thousands" of places within a reasonable distance that do GM's (or any other manufacturer's for that matter) warranty work, nor will they always have the parts available to do such work immediately. The car I mentioned in my first post in this thread was in fact a GM vehicle, which took over a week to have the issue resolved.

There isn't a dealer out there that will drop everything on a Saturday afternoon to do warranty work on a car's A/C. A promise for Monday, in my experience, is definitely better than par for the course for this type of issue.

As for the other person's issue you mentioned, a "buzzing sound" that doesn't hinder operation of anything definitely is not going to be a priority for any servicer... I would be disappointed if Tesla *did* prioritize such a thing. And I highly doubt that they refused to look at it and instead refused to look at it immediately and they would schedule an appointment... as has been my experience with Tesla and other brands.

I guess we'll agree to disagree on this one. I've had cars fixed same-day many, many times. You're wrong, at least based on my experience. Maybe we live in different parts of the country and get different service. I've been driving since I was 16, 1976, so I feel I know a little about cars, driving and car repairs.

 

[wk057]

I guess we'll agree to disagree on this one. I've had cars fixed same-day many, many times. You're wrong, at least based on my experience. Maybe we live in different parts of the country and get different service. I've been driving since I was 16, 1976, so I feel I know a little about cars, driving and car repairs.

I feel like you're being vague in an attempt to save face here, it seems. I've also had cars have some problems fixed same day many times. My Model S is included on that list.

However, I've never had an A/C compressor replaced same day under warranty, or any other major repair done same day. I think the best I've done on an auto A/C repair in the last 20 years was two days from broken to fixed.

And things have certainly changed quite a bit in the 20 year gap between when you started driving and when I did... so, a few decades of now-useless stats on this matter potentially clouding your side of this argument. In the 70s/80s the stats for service times was most likely much different than today. Auto service has changed substantially in the past decade alone with the introduction of so much more technology.

It is also worth noting that with the A/C specifically any HVAC tech could check out the sealed system portion of things. It could be something as simple as low refrigerant pressure tripping a low pressure switch not allowing the compressor to turn on. So, not limited to Tesla for this portion at least.

 

[jerry33]

However, I've never had an A/C compressor replaced same day under warranty, or any other major repair done same day. I think the best I've done on an auto A/C repair in the last 20 years was two days from broken to fixed.

My driving days reach back to the 60s and I've never had an A/C repair (other than just topping up refrigerant) done in a day either. However, when the main charger stopped charging in my Model S while I was on vacation Tesla flew in a Ranger to fix it. As I had enough charge for the two days of driving--phoned on Saturday, fixed on Monday--I never actually lost any driving time other than the couple of hours it took for the replacement charger to be installed. I've never had that kind of service from any dealer. Note that it could have been much different if it had conked out at one of the RV park charging stops (only two active Superchargers back then and they were in California).

 

[JPP]

My AC went out a few months ago. Got a prioritized repair (since the same coolant loop affects the pack cooling). Turned out a pressure fitting on the compressor loosened and I lost all of the refrigerant. Fittings tightened--system recharged. All good.

 

[cwave1]

You won't believe this but after reading this story on Sunday morning, I went to go somewhere and discovered that my AC is also now broken where it had been working the previous day. While I'm going to receive prioritized service, they are providing an ICE loaner as no Teslas are available on short notice.

I guess I need to stop reading these stories

 

[FlasherZ]

If a GM car's AC fails you have many more options for getting it repaired, as there are hundreds of thousands of repair centers that can take on fixing just about anything on a GM car.

They can't do it under warranty. It's off to the dealers for that.

Years ago, I experienced a GM A/C compressor that suffered such a critical failure that it would stop the engine when the clutch engaged. I called several dealers, and not a single one of them wavered from their standard approach - they scheduled an appointment to look at it about a week later; if it was determined to be the compressor, they could have the part in 2 days (they wouldn't pre-order it as Tesla sometimes does), and then have it back to me a few days later when the repair would fit in their schedule.

Keep in mind this was NOT just a matter of the A/C not working - this literally stopped an idling engine when the A/C compressor tried to kick in. I disconnected the wiring connector from the clutch so it wouldn't try to engage the compressor so that I could drive the car while I was on the waiting list.

 

[mknox]

My driving days reach back to the 60s and I've never had an A/C repair (other than just topping up refrigerant) done in a day either.

Not to get in to a squabble, but at least as a data point... I have. I had a GMC Envoy and the A/C suddenly started to make a loud howling noise, but it still worked. I thought it was probably a tensioner or idler pulley. My dealer took me straight in, discovered it was the bearing in the compressor and had the compressor changed out and back to me the same day, all under warranty. Even gave me a loaner car for the day.

 

[jomo25]

The service center called me this morning at 7:14AM. I'll bring it in to them this AM and they will give me a loaner. Hopefully, it won't take too long to fix. So, kudos that they got back to me as soon as the center opened this morning (as I kind of expected).

 

[apacheguy]

Actually this is a more serious issue on the MS than any other car since the drivetrain relies on the AC compressor. What if you're in the middle of a road trip, the compressor craps out, and as a result the car won't SpC? That'd really suck.

 

[ddimit]

Unless i'm missing something major here there seems to be some confusion about Cabin HVAC and Battery pack cooling. I was under the impression that that battery pack was cooled by a closed loop glycol system that is separate for the cabin HVAC which is a Freon based system run by an electric compressor instead of a belt driven compressor like normal ICE vehicles.

Am I wrong ion my assumption?

 

[ThosEM]

We had exactly the same syndrome develop a few weeks ago; sudden complete failure of the HVAC. The warranty repair invoice states that the DC/DC converter internal fuse was blown, but they replaced both the compressor that blew the fuse by drawing too much power, and the DC/DC converter itself. It's not clear why replacing the fuse would not have corrected that.

It surprises me that the compressor requires its own DC/DC converter,(nothing else failed). I guess that means it is running off the high voltage battery, rather than the 12 V system. I wonder what else runs from the high voltage battery? Brakes, power steering, panoramic roof? Anyone have more insight into that?

 

[apacheguy]

Unless i'm missing something major here there seems to be some confusion about Cabin HVAC and Battery pack cooling. I was under the impression that that battery pack was cooled by a closed loop glycol system that is separate for the cabin HVAC which is a Freon based system run by an electric compressor instead of a belt driven compressor like normal ICE vehicles.

Pretty sure the coolant lines are separate, but still run off of the same AC backend hardware. You can hear the compressor fire up when SpC in heat even if cabin AC is disabled.

 

[FlasherZ]

Unless i'm missing something major here there seems to be some confusion about Cabin HVAC and Battery pack cooling. I was under the impression that that battery pack was cooled by a closed loop glycol system that is separate for the cabin HVAC which is a Freon based system run by an electric compressor instead of a belt driven compressor like normal ICE vehicles.

Am I wrong ion my assumption?

I thought there was a heat exchanger as part of the equation.

 

[wk057]

We had exactly the same syndrome develop a few weeks ago; sudden complete failure of the HVAC. The warranty repair invoice states that the DC/DC converter internal fuse was blown, but they replaced both the compressor that blew the fuse by drawing too much power, and the DC/DC converter itself. It's not clear why replacing the fuse would not have corrected that.

It surprises me that the compressor requires its own DC/DC converter,(nothing else failed). I guess that means it is running off the high voltage battery, rather than the 12 V system. I wonder what else runs from the high voltage battery? Brakes, power steering, panoramic roof? Anyone have more insight into that?

Generally if a fuse blows, it blows for a reason. Replacing the fuse isn't generally the solution.

Also, the compressor doesn't have it's own DC-DC, it just gets it's HV DC connection at the 12V DC-DC converter, which is used as a HV DC junction box of sorts.

 

[JER]

I thought there was a heat exchanger as part of the equation.

According to the image below, yes. Three fluid circuits - two coolant and one refrigerant. Both cabin and battery can be cooled; while there are separate pumps for each load, they share the same working fluid.

No doubt this is how the pack maintains such a good life despite supercharging. If the battery were at anything like the temperatures Kman's recorded at those side radiators/condensers, it would die in no time.

 

[Electricfan]

I feel like you're being vague in an attempt to save face here, it seems. I've also had cars have some problems fixed same day many times. .

When did I "lose face"?

 

[jomo25]

The service center called me this morning at 7:14AM. I'll bring it in to them this AM and they will give me a loaner. Hopefully, it won't take too long to fix. So, kudos that they got back to me as soon as the center opened this morning (as I kind of expected).

Of course, when I drive the car into the SvC this morning, the HVAC was working. I didn't even try to drive it yesterday since it was another summer day in PHX. And even if it was working, I'd not want to chance another outage.

When I got to the SvC and explained the issue, the service agent noted that they likely knew the exact issue as they've had a few others have similar issues in the recent heat wave. The low pressure sensor/transducer connector needed to be replaced. He noted that this part has proven problematic occasionally, especially in very high heat, and needed to be replaced with a newer version of the part. He said that it would likely eventually completely fail if not replaced. But prior to it, it would fail only intermittently. Sometimes for just brief periods of time.

(Side note: This triggered a realization that I have noticed the AC system blowing intermittently "not as strong" recently. It never blew hot air, but sometimes would blow more lightly. I thought it might have been just the recent firmware updates, but apparently it was related to this issue.)

Anyways, it was replaced within a few hours and it worked fine on the ride home. I can only assume and trust this takes care of it all. So, a positive experience overall as usual.

 

[Tyl]

jomo25...... Great post... Thank you! Great to learn what to look for and the easy fix should the HVAC fail in our high desert heat.

 

[JER]

The low pressure sensor/transducer connector needed to be replaced.

Presumably, that's there to prevent the pumps running if the loop has lost its normal charge of refrigerant. That's probably the better failure compared to having the pumps run without lube and sieze.

 

[apacheguy]

@jomo - Did the MCU display any errors or alerts indicating that the low pressure sensor was faulty? It shouldn't be that difficult for the vehicle to self diagnose since presumably it reads the state of that sensor. No reading = faulty sensor. It should generate an alert stating as much to the driver.