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DC - DC converter / AC compressor repair

Discussion in 'Model S' started by biotour, Jan 17, 2019.

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  1. ElectricEel

    ElectricEel Member

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    If a fuse is all it takes to fix the AC compressor I am going to crap my pants laughing at Tesla. It would be a shame they replace the whole thing instead of replacing a $10 part.
     
  2. sledom

    sledom Member

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    The A/c worked, I pulled the power in August to replace the motor, when power came back on the a/c went out, I think it must have spiked power when the HV was reconnected... So a replacement of the compressor wouldnt help, I dont think. Ill know for sure tomorrow
     
  3. brkaus

    brkaus Well-Known Member

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    I'd be worried about something more expensive, like the house the car is parked in.

    Keep us updated! Ongoing maintenance cost us a big concern if mine. I'm a DIY kinda person, so these type of projects make me feel better.
     
  4. sledom

    sledom Member

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    Annnnd. It works. Just needed fuses. No heater core. Not sure about ac because of current temps but confident that is working as well
     
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  5. ElectricEel

    ElectricEel Member

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    interesting, this needs to be put into a sticky with other easy fixes to tesla's
     
  6. D.E.

    D.E. Uncorked

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    Well, that’s just nuts. There are fuses. Tesla knows they blow. Then they make a deliberate design change so I can’t replace these replaceable fuses?

    They should put them right out there on top, and maybe give me a couple of spares. Or maybe put in a breaker. My house doesn’t have fuses. Houses haven’t had fuses for what, 60 years? These aren’t pre WWI era horseless carriages, they’re really advanced space age machines. They’re advanced machines on the surface but they’ve apparently got old time technology underneath and Tesla doesn’t want me to be able to do the old time replacement of their old time fuses.

    I love my Tesla, the car, but sometimes I get the idea Tesla, the company, doesn’t like me. Every time they do something like this it makes me feel just a little bit less loyal. That should bother them. Soon everyone will be producing electric cars. My loyalty is all they’ve got. This loyalty thing is a two way street, once they’ve used it up, it’s gone.
     
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  7. swegman

    swegman Active Member

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    Many many years ago (when gas was cheap and nobody knew anything about fuel economy) I drove a 1972 Pontiac Grand Prix. I would drive the car with the A/C blasting to really low temperatures. About once a year the A/C would stop operating. The system had some sort of a fuse (maybe temperature related) that woukd blow. It was located in physical contact with the compressor under the hood. I kept spares and would replace it as needed. Took less than a minute to “repair” the system.
     
  8. Gixx1300R

    Gixx1300R Member

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    This is what I have found. My fuses blew in the DC to DC converter. Tesla replaced the converter, battery and cooling pump. When I got my parts back I checked them, The 12v battery and the pump was good. 2 fuses had blown in the DC to DC converter. I believe Tesla does not teach the service centers on repairing such parts as these, only switch them out and return the parts back to Tesla to be refurbished. By doing this Tesla makes and saves big $$$$ by having the customer pay thousands for repairs and getting parts back that function just fine or takes only a fuse replacement to repair.
     
  9. brandonk

    brandonk Member

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    is there a guide somewhere on how to access the dc to dc converter, open it up, and check / replace the fuses?
     
  10. mongo

    mongo Well-Known Member

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    Houses have varied loads so breakers make sense (hair dryer and curlers tripping the breaker), or a bad cord in an appliance. In the case of vehicle with fixed loads, an overload is (usually*) an indication that something has failed. Cars do not typically have nuisance trips.

    The fuses are clip mounted, that does not mean they are meant to be replaced. Each cycle of the holder has a detrimental effect on the contact resistance. The level of training and equipment needed to reliably remove, decap, replace, and reassemble a part with warranty is far removed from that needed to swap a module. If the fuse even is the root cause or any specific module...

    *if the inrush is near the high end of the fuse range, it could just fail after a number of cycles.
     
  11. D.E.

    D.E. Uncorked

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    “Houses have varied loads so breakers make sense (hair dryer and curlers tripping the breaker), or a bad cord in an appliance. In the case of vehicle with fixed loads, an overload is (usually*) an indication that something has failed. Cars do not typically have nuisance trips. “

    But fuses do sometimes fail, that’s the experience of the people who started this thread. They fixed the fuse and it fixed the problem. The fuse is a replaceable part. True it should last forever, and I do understand a fuse interrupting power is protection for downstream wiring. I don’t buy into the holder resistance argument, contacts can be treated so they don’t degrade or better they should be made to avoid degradation. The fuse is by design replaceable, to have it in a holder that doesn’t support same resistance replacement is just poor design. Maybe that view exposes my ignorance. By all means, enlighten me. Until then I’ll continue to think there’s technology that can allow a fuse holder to work properly for the life of the device in which it is installed.

    I do understand your point. Fuses are there for a reason. They protect. Tesla doesn’t want me mucking about with it.

    That 4 year warranty is nice. It’ll be gone, though. At that point I’ll be paying to get at that fuse, whether through Tesla or perhaps a 3rd party garage. It’ll make a difference whether that fuse is a $50 replacement or a $2000 replacement. At that time it’ll be important to check the components protected by that fuse as well as to replace the fuse itself. For Tesla to make that process needlessly difficult and wickedly expensive just doesn’t seem to be in my best interest.
     
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  12. mongo

    mongo Well-Known Member

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    Sure, like I said it may be the fuse is being operated at the edge of its reliability. Especially if the PTC heater inrush is not well controlled.

    Design for repairability adds cost and complexity. It also opens up further liability in case the fix is done wrong. Cost optimized designs tend to be hard to work on. Gluing a lid on is faster and cheaper than screwing. At least it's not fully potted....

    All spring type connections have a insertion/ removal cycle life. Automotive connectors can start showing issues in as few as 5 cycles, plug in style fuses in one if they are rocked to remove.
    If someone pops the fuse out with a screwdriver between the fuse and terminal, they can permanently deform the holder. Then after a few cycles, resistance goes up, heat occurs, maybe arcing.

    I'm also guessing there are limited styles of 600V 40A fuses so there may not be a permanent style. There are screw down styles, but that is less manufacturing friendly.
     
  13. scaesare

    scaesare Well-Known Member

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    Thanks for the thread. This is good to know. I just replaced a fuse in my secondary charger that had failed (2nd time.. first was in the primary charger), and it's back in service for $4 and an afternoon's worth of effort.

    This sound similar. As @mongo mentioned, I think the thermal stress and vibration can fatigue the fuses over time. If/when I experience A/C & & heater probs on my nearly 6-yr old Model S, I'll give this a try.

    Any tips & tricks you can share in getting the DC-DC out are always appreciated.
     
  14. Gixx1300R

    Gixx1300R Member

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    Not yet, there is nothing on YouTube
     
  15. sledom

    sledom Member

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    Im thinking about doing something on the youtubes in the vain of Rich rebuilds. But maybe a little more technical, so you know what your doing not just seeing someone doing it. If that makes sense.
     
  16. sledom

    sledom Member

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    I would normally agree, however to me this feels alot like a money grab. Contrary to what elon has said I think that Tesla is looking for a type of car buyer that knows nothing of cars and has no desire to fix anything, more money than they have sense. THat way they dont wuestion when a part breaks, the part is just bad.

    If this had an external fuse the process would have been so much easier and no where near the hassle.
     
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  17. sledom

    sledom Member

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    I cant agree more this is exactly how I feel, given my car does have a salvage title I didnt know that I would be treated sub-human. Is my money not as green as the guy with a clean title? If they would have let me pay I wouldnt be getting into the weeds with fixing things I could take it in and have them take my money to solve my problems. lots of questions maybe Elon forgot what it was like to not be a billionaire.
     
  18. mongo

    mongo Well-Known Member

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    If it was an external fuse then there would be am exposed 400V connection. So then they need to add a cover with a cover missing switch to the safety circuit. Then, if someone neglected to disable the safety loop and accidentally pushed said cover switch while changing the fuse...

    Tesla doesn't want to be serving Teslas, they are designing for longevity, not repair-ability.
     
  19. sledom

    sledom Member

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    #59 sledom, Jan 30, 2019
    Last edited: Jan 30, 2019
    That thread looks good, ill have to check it out.
    as far as tips and tricks go
    ************This is super easy, yes you can do it yourself, minimal tools required************************
    ***** WEAR PPE AND ALWAYS CHECK WITH YOUR METER BEFORE TOUCHING ANYTHING EXPOSED THAT IS ORANGE IN COLOR HIGH VOLTAGE CAN KILL YOU*****
    Let me break down the process.
    -Disconnect power. 12v and high power- CHECK POWER IS OFF WITH METER
    -Remove passanger front wheel
    -remove wheel well liner, its attached by 3 or 4 plastic clips. Doesnt need to be completley out, just out of the way.
    -In plain view for the world to see is the fully accessible DC-DC converter.
    -Two clamps from my woodworking area, one to each coolant hose.
    -disconnect coolant hoses, you can do it at the hose clamp and remove the hose or the whole fitting is attached with 4 screws on each one, thats what I did is take the screws out, it was easier than discnnecting the hose as it was being difficult.
    -Next remove all 4 connectors, and then remove the grounding wires by taking the nuts off the wire.
    -Remove the housing and two HV cables coming from the battery.
    -Remove the black clips around the edges which help route other wiring.
    - The DC-DC converter is attached to the body of the car with 2nuts and one bolt, once those are removed the whole thing comes out, its a little difficult as the mounting is akward, youll know when you see it what Im talking about but if you wiggle it a bit you will get it off. (I used a drill to bore out the mounting location on the DC-DC converter itself it didnt affect anything and really helped when putting it back in.)


    -The hardest part is this, separating the converter, the gasket is sealed well,Remove the 6 screws around the outside of the housing then start on the gasket. Im sure there are lots of ways to do it but I used a hammer, razor blade and a screw driver to separate the two pieces, being careful to not drive the screw driver inside but only around the edges so that it would make a gap big enough to get my razor in to cut the gasket. DO this all the way around.
    -after its separated the hard part is over, there are a total of 4 fuses, check them all with your meter, replace what is bad. (with an identical fuse)
    - Now clean off the rest of the old gasket and replace with a liquid gasket from the autoparts store, this is very important so that you dont get water in here and develop a real problem later on.
    -Seal it up and put it back in.
    -turn heat/AC on and enjoy :) .

    PS if you break the plastic clips on the tire area you can replace them from ebay, I dont know why but they are priced like gold at autozone and you can get 100 for a like 2$ on ebay.
    -using the razor blade clean off the old gasket and


    Tips?
    DO NOT REMOVE THE HEATER. I did and it just costed alot of time, added nothing to the whole process, I had to reinstall the heater just to check it so you know, I should have just started with the DC-DC and been good
    Tricks?
    Dont be scared its super easy and itll save you a ton of money.
     
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  20. sledom

    sledom Member

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    Yes.
    My thought was a small housing on the unit that had 4 screws on nuts, whatever. THe plastic of the housing would be Bright orange like the other HV coloring and a warning on the plastic. once the screws are removed the plastic can be removed and there are 2 large fuses that can be removed and replaced.
     

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