Access to the heater assembly?

[JSD17]

Does anyone know if the fuse on a 2012 Model S is for heating only or for both heating and A/C?

The heating in my '12 Model S does not work (very minimal heat with fans low on drivers side only) but the A/C works. If the fuse is responsible for both, would that mean I am safe to just change the PVC heater or should both still be changed?

Any help is appreciated.

Thank you!

 

[hkpaul]

Does anyone know if the fuse on a 2012 Model S is for heating only or for both heating and A/C?

The heating in my '12 Model S does not work (very minimal heat with fans low on drivers side only) but the A/C works. If the fuse is responsible for both, would that mean I am safe to just change the PVC heater or should both still be changed?

Any help is appreciated.

Thank you!

If the heater doesn't work, most likely both the heater is shorted / malfunction causing the fuse to be blown. I literally just replaced my PTC coil fuse. You can go to Youtube and find the video to see how it's replaced. Highly suggest to replace both since your 2012 PTC heater likely Gen1 and it's prone to be bad. They upgraded it. Please refer to the video "Tesla Model S: DC-DC Fuse+PTC Heater replacement (DC-DC converter removal)" (there are 5 videos) it's super detail! Hope this help and hope your model s can keep running strong!

 

[JSD17]

If the heater doesn't work, most likely both the heater is shorted / malfunction causing the fuse to be blown. I literally just replaced my PTC coil fuse. You can go to Youtube and find the video to see how it's replaced. Highly suggest to replace both since your 2012 PTC heater likely Gen1 and it's prone to be bad. They upgraded it. Please refer to the video "Tesla Model S: DC-DC Fuse+PTC Heater replacement (DC-DC converter removal)" (there are 5 videos) it's super detail! Hope this help and hope your model s can keep running strong!

My issue is different. The heater works but only on the drivers side. I changed the actuator and the issue persisted and now Tesla says it’s a failing PTC heater. The fuse still works because I’m getting heat, but I’m not 100% sure if a failing PTC can make exactly half of the car hot (drivers side windshield, face, and footwell) and the passenger side cold as if the A/C is on.

 

[Cheburashka]

My issue is different. The heater works but only on the drivers side. I changed the actuator and the issue persisted and now Tesla says it’s a failing PTC heater. The fuse still works because I’m getting heat, but I’m not 100% sure if a failing PTC can make exactly half of the car hot (drivers side windshield, face, and footwell) and the passenger side cold as if the A/C is on.

I don't think that makes logical sense to me. The PTC heater is just that.. an electric heater. It either works or it doesn't and it doesn't have any "sides".

 

[KArnold]

I don't think that makes logical sense to me. The PTC heater is just that.. an electric heater. It either works or it doesn't and it doesn't have any "sides".

Is there a separate thermostat for the passenger side for split zones? Maybe that has failed at some low temperature.

 

[Cheburashka]

Is there a separate thermostat for the passenger side for split zones? Maybe that has failed at some low temperature.

Yep that would make the most sense. Either something to do with the thermostat, possibly wiring, or the actual mechanism for air circulation.

 

[JSD17]

Yep that would make the most sense. Either something to do with the thermostat, possibly wiring, or the actual mechanism for air circulation.

Would this be something inside the heater - or should we check something else?

The heater used to work so I don't know if it can be a wiring thing unless you mean one of the wires broke? Is there a passenger side temperature sensor inside the PTC heater? If that is the case, replacing the PTC heater should correct the issue. I'm conflicted now. I've already had 3 different diagnostics and all 3 had the passengers side actuator initially (I guess it was failing or giving a code). I replaced that, and now the heat is better on the drivers side somehow, but nothing changed on the passengers side.

I took it to Tesla to finally diagnose and they're saying failing PTC heater. Knowing Tesla, I should maybe take their diagnosis with a grain of salt - but I'm not sure how to proceed right now. Any chance it can be a sensor inside the PTC which will cause replacing the PTC to fix this? Worst case scenario would be to replace the PTC and still have the same issue which is why I'm a little hesitant to proceed that route right now.

 

[Gtech]

Would this be something inside the heater - or should we check something else?

The heater used to work so I don't know if it can be a wiring thing unless you mean one of the wires broke? Is there a passenger side temperature sensor inside the PTC heater? If that is the case, replacing the PTC heater should correct the issue. I'm conflicted now. I've already had 3 different diagnostics and all 3 had the passengers side actuator initially (I guess it was failing or giving a code). I replaced that, and now the heat is better on the drivers side somehow, but nothing changed on the passengers side.

I took it to Tesla to finally diagnose and they're saying failing PTC heater. Knowing Tesla, I should maybe take their diagnosis with a grain of salt - but I'm not sure how to proceed right now. Any chance it can be a sensor inside the PTC which will cause replacing the PTC to fix this? Worst case scenario would be to replace the PTC and still have the same issue which is why I'm a little hesitant to proceed that route right now.

Which actuator did you changed? Could you move the flap by hand? Could be blocked.

Well, you could remove the PTC partially and check with an infrared thermometer if the passenger side is getting as hot as the driver side. I believe there are temp sensors in the PTC since those faults can popup, I assume you already checked service mode?

When you remove PTC you can also see how heat is distributed to the channels or you can search Google for HVAC assembly Tesla Model S

 

[JSD17]

Which actuator did you changed? Could you move the flap by hand? Could be blocked.

Well, you could remove the PTC partially and check with an infrared thermometer if the passenger side is getting as hot as the driver side. I believe there are temp sensors in the PTC since those faults can popup, I assume you already checked service mode?

View attachment 994560

When you remove PTC you can also see how heat is distributed to the channels or you can search Google for HVAC assembly Tesla Model S

Thanks, I've done that. The only alert I saw related to the heating I believe was: THC_d0021_RCCMActuator and THC-w0176_MCUCanTmo (but don't think this is related to heat?)

I'm unsure if that's related to the PTC Heater?

The actuator that I replaced (by Tesla) was the Front Passenger Side Temperature Actuator. Three different shops told me that was giving an error code. That actuator was broken, one of the teeth were chipped - but still my passenger side is getting no heat - changing it made my drivers side heat stronger though, on all 3 vents - footwell/face/and windshield - but all 3 on the passenger side remain cold like the A/C on.

The issue I currently have is I'm not planning on diagnosing/changing it myself. I was going to take it to a shop to get replaced as to not deal with the HV battery and make sure everything is changed correctly. So I won't be the one opening it and checking. Already paid Tesla for a diagnostic who told me it was the PTC, which I'm hoping is correct - but I'm not sure if the symptoms add up.

I'm thinking of buying a used PTC and asking a third party shop (who works with Tesla's) to replace it.

 

[JSD17]

I don't think that makes logical sense to me. The PTC heater is just that.. an electric heater. It either works or it doesn't and it doesn't have any "sides".

Think you were right.

Tesla's diagnosis of PTC heater failing seemed to have just been a guess.

Of course I buy a new PTC Heater online and have it replaced at a third party shop and the same issue - cold air on all passenger side vents (face/foot/windshield) and hot air on all drivers side vent. I'm now led to believe that Tesla just guessed my PTC was failing incorrectly. I asked the shop that replaced the PTC if it could be related to the fuse and they said no - because my car is getting heat on one side the fuse cannot be blown.

Tried to make a new appointment with Tesla and they want to charge a new diagnostic fee for the same issue. Is there any recourse for this? They already charged me and seemed to have just guessed what the issue was - and now I'm out nearly $1000 by having another shop replace what appears to be a fully functioning PTC. Of course, I can't blame the shop as they just did as I instructed - but is another diagnosis fee for a misdiagnosed issue normal?

 

[Gtech]

Think you were right.

Tesla's diagnosis of PTC heater failing seemed to have just been a guess.

Of course I buy a new PTC Heater online and have it replaced at a third party shop and the same issue - cold air on all passenger side vents (face/foot/windshield) and hot air on all drivers side vent. I'm now led to believe that Tesla just guessed my PTC was failing incorrectly. I asked the shop that replaced the PTC if it could be related to the fuse and they said no - because my car is getting heat on one side the fuse cannot be blown.

Tried to make a new appointment with Tesla and they want to charge a new diagnostic fee for the same issue. Is there any recourse for this? They already charged me and seemed to have just guessed what the issue was - and now I'm out nearly $1000 by having another shop replace what appears to be a fully functioning PTC. Of course, I can't blame the shop as they just did as I instructed - but is another diagnosis fee for a misdiagnosed issue normal?

Like I mentioned above maybe teeth where chipped because the flap inside the assembly is stuck. So it could be the old actuator broke because of to much resistance.

Maybe when you or a mechanic can remove the actuator you can check if it's possible to control the flap by hand (or not) to see if temperature changes

This actuator is accessible when removing the glove box

 

[JSD17]

Like I mentioned above maybe teeth where chipped because the flap inside the assembly is stuck. So it could be the old actuator broke because of to much resistance.

Maybe when you or a mechanic can remove the actuator you can check if it's possible to control the flap by hand (or not) to see if temperature changes

This actuator is accessible when removing the glove box

Tesla service was the one to replace my passenger front temperature actuator though - 1 day before false diagnosing my PTC heater. I assume they checked it was working after they changed it.. but with Tesla you never know.

They’ve so far agreed not to charge me for a new diagnostic after misdiagnosing my heater and having me replace my PTC for no reason telling me it was the problem after changing the actuator didn’t solve the problem. The problem was I requested to change the actuator without a diagnostic fee so I think knowing Tesla the rep saw that it was broken but said f it, now that I paid a diagnostic - they don’t want to admit they didn’t check to see if the new actuator was working.

Also - this new PTC? makes a buzzing sound around fan speed 7 only if air circulation is off. It doesn’t matter if it’s cold or hot air. Does all air run through the PTC heater or was it just a coincidence that I’m now noticing?