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DC - DC converter / AC compressor repair

biotour

Member
Jan 17, 2019
59
50
sf bay area
so my 2013 model S is not blowing cold air anymore. Also, the heater is no longer blowing hot air. No error messages, but from research I believe the AC compressor and possibly PTC died causing the dc/dc fuse(s) to blow. The vehicle is out of warranty and i'm not trying to spend $4k to fix.

Will driving with it unfixed potentially cause a battery degradation issue? as the AC is used to cool battery while supercharging? Even though its cold outside?

Can I buy a new compressor and vacuum out the r134a, bolt up new unit, and recharge, with the vehicle off?

Can i just throw in some new fuses in the DC-DC? Or does it need replacement?
 

sledom

Member
Nov 2, 2017
155
109
99216
Im having the exact same issues, first my A/C quit working after I replaced the motor. No big deal I thought. Now half way through winter the heater quit working. I bought a new (used) PTC and Im going to be installing it. IF that doesnt fix the issue I will look into the dc-dc.

I am thinking that because the 12v system is working that its not the dc-dc and that these are isolated issues but it is strange that you are having the same issues. Did your ac and heater die at the same time?

Im not aware of any fuses on the dc-dc converter, If I get to the point that I pull mine I will take it apart and check it out for fuses.

Mine is rebuilt so I cant take mine to SC. MAybe you could go the service center for them to diagnose it and then fix it yourself, could help us both out, knowing exactly what is wrong with it. :)


Please keep me posted, as I will let you know what I find out. ;)
 

Gixx1300R

Member
Dec 30, 2017
754
1,271
orlando
There are 3 fuses in the DC to DC converter
DC to DC converter (2).jpg
 

sledom

Member
Nov 2, 2017
155
109
99216
All right I got all up in it today and got to the heater, removed it and now Im waiting for the replacement. I wanted to get to the dc-dc but I only need to do that if isnt working. ANy idea what the dc-dc powers???

I see on the unit that it powers the compressor I assume thats for the air suspension
PTC heater- thats not working
Battery heater- I dont know how to check if that is working.

Where does the A/C get its power from?
 

brkaus

Well-Known Member
Jul 8, 2014
8,288
6,844
Austin, TX
I see on the unit that it powers the compressor I assume thats for the air suspension
PTC heater- thats not working
Battery heater- I dont know how to check if that is working.
Pretty sure compressor is the air conditioning compressor.

The compressor is variable speed from what I have read, so there might be several dc/dc conversation modules in the dc/dc unit?
 

sledom

Member
Nov 2, 2017
155
109
99216
Pretty sure compressor is the air conditioning compressor.

The compressor is variable speed from what I have read, so there might be several dc/dc conversation modules in the dc/dc unit?
Right you are, I just got the thing out of the car and taken apart. ill post some pictures. THe two large fuses appear to be bad but Im not positive on how to check them. I ran the meter accross and they do not ohm. But they dont look like normal fuses so maybe im doing it wrong.
 

mongo

Well-Known Member
May 3, 2017
14,002
45,565
Michigan
Right you are, I just got the thing out of the car and taken apart. ill post some pictures. THe two large fuses appear to be bad but Im not positive on how to check them. I ran the meter accross and they do not ohm. But they dont look like normal fuses so maybe im doing it wrong.
You are likely doing it right. 40 Amp 700V fuse, around $38 from Newark..
If you measure 0 when connecting your test leads together, but open when testing the fuse, it's bad.
 

swegman

Active Member
Mar 27, 2012
1,580
1,642
I just happened to talk to a mobile technician yesterday about this while he was replacing a door handle mechanism in my 2013 P85 car.

I mentioned that I had spare fuses for the dc-dc converter in the event the AC stopped working, based on a thread I had read in TMC. He told me that the fuses would often blow in the dc-dc converter for no apparent reason, and that the HVAC system would operate fine once the fuses were replaced. He indicated that with the early model S (like mine) you could open the dc-dc converter easily to replace the fuses. However, he indicated that once Tesla learned that people were replacing the fuses themselves, they redesigned the dc-dc converter so it can no longer be opened without damaging the housing.

If you can easily open the dc-dc converter, check the fuses before replacing other components.
 

sledom

Member
Nov 2, 2017
155
109
99216
I just happened to talk to a mobile technician yesterday about this while he was replacing a door handle mechanism in my 2013 P85 car.

I mentioned that I had spare fuses for the dc-dc converter in the event the AC stopped working, based on a thread I had read in TMC. He told me that the fuses would often blow in the dc-dc converter for no apparent reason, and that the HVAC system would operate fine once the fuses were replaced. He indicated that with the early model S (like mine) you could open the dc-dc converter easily to replace the fuses. However, he indicated that once Tesla learned that people were replacing the fuses themselves, they redesigned the dc-dc converter so it can no longer be opened without damaging the housing.

If you can easily open the dc-dc converter, check the fuses before replacing other components.
THat is good to know! The fuses (both) look bad I will order parts I took a bunch of pictures im trying to load them but struggling with my internet connection right now. Ill replace the fuses and get back to you.
Getting the dc-dc converter out was a breeze way easier than I thought it would be, but getting it open was a pain in the butt! It has some gasket material in there that wont budge, man took me half an hour with a flat head and a hammer+ razor blade. Razor blade is a must.
 

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