Results 1 to 25 of 25

Thread: HVAC / Blower fan - Can it be reversed ??

  1. #1
    Modulator Southo's Avatar
    Join Date
    Nov 2001
    Location
    Sydney, NSW
    Posts
    7,140

    HVAC / Blower fan - Can it be reversed ??

    Have a new electric motor for the HVAC in my X-Trail, but it runs anti-clockwise (and I need it to run clockwise as I can not reverse the fan)
    Can the two wires (there are only two running to the motor) be safely swapped (ie, Pos to Neg and Neg to Pos) in order to reverse the rotation of the fan motor - or are they wound a special way and have to be run that way ??

  2. #2
    bitch lasagne Bob Vegana.'s Avatar
    Join Date
    Apr 2002
    Location
    United Nanny States of Australia
    Posts
    5,073
    You bought a LHD one, because fuck the dealerships?
    Quote Originally Posted by brewdles View Post
    In short, some cunt at test and tune had a 250cc honda turning to 11ty and it sounded porn. Do that.

  3. #3
    Unregistered User Permit Roadsailing's Avatar
    Join Date
    Aug 2003
    Location
    melbourne
    Posts
    5,493
    Sometimes you can, does it have an impeller on it? If so it's a bit more complicated. Unlikely to blow it up by giving it a go. Probably.

  4. #4
    Modulator Southo's Avatar
    Join Date
    Nov 2001
    Location
    Sydney, NSW
    Posts
    7,140
    Quote Originally Posted by Mr Flibberty Gibbets View Post
    You bought a LHD one, because fuck the dealerships?
    Nah, fuckers sent the wrong one...

    Local Stealership wanted $290+
    Local ebayers - around $115
    Ali-Express - $38.90 - X-TRAIL 27225-8H31C 272258H31C RHD 27225-8H60B, 272258H60B

    Ordered the correct RHD one but they sent me the wrong one - and I CBF waiting another 3-4 weeks for them to replace it (especially as my dash is in eleventy million pieces at the moment

    I also modded the one they sent me to replace the bushes (that always flog out) with proper sealed bearings, so would rather get this one working if possible...

    Quote Originally Posted by Roadsailing View Post
    Sometimes you can, does it have an impeller on it? If so it's a bit more complicated. Unlikely to blow it up by giving it a go. Probably.
    The fan part is removable - so it's just the actual motor that I need to reverse to utilise the same fan...



  5. #5
    Registered User
    Join Date
    Jun 2015
    Location
    West Pennant hills
    Posts
    111
    Pretty sure my old 12v slot car motor used to run backwards if you got the polarity reversed. Can't see why a fan motor would be any different.... no responsibility taken if it all goes tits up !!

  6. #6
    Unregistered User Permit Roadsailing's Avatar
    Join Date
    Aug 2003
    Location
    melbourne
    Posts
    5,493
    can be a bit tricky to get the impeller off, pretty easy to put them on. (your photo looks suspiciously like a VE commodore motor, they have offset brushes from memory but should still run backwards kinda OK). the only issue is the "timing" of the coils to the permanent magnets in the housing (motors can be optimised this way for torque or efficiency for whatever RPM range) it might not run great in the opposite direction but should still work.

    Most manufacturers design HVACs so you can change the blower motor by just taking out the glovebox (or not even that much work) so hopefully if it runs shit you can replace it with the proper Chinese knockoff down the track.

    EDIT: does the motor go directly into the blower scroll? LOL Datsun.

    your best bet for reversing polarity (after confirming it will run backwards without catching on fire) is to de-pin the blower plug and swap them over. Blower motors draw big current so twist&tape is not recommended.
    Last edited by Roadsailing; 10-05-17 at 07:19 PM.

  7. #7
    Non Compos Mentos Gammaboy's Avatar
    Join Date
    Jun 2008
    Location
    Brisbane
    Posts
    14,341
    Only other concern might be the lock nut on the end - it may be LH thread on one of them to stop the nut being spun off.
    "Where can we get hold of a Vincent Black Shadow?" "Whats that?" "A fantastic bike," I said. "The new model is something like two thousand cubic inches, developing two hundred brake-horsepower at four thousand revolutions per minute on a magnesium frame with two styrofoam seats and a total curb weight of exactly two hundred pounds."

  8. #8
    Registered User E-Z's Avatar
    Join Date
    May 2011
    Location
    sunshine coast
    Posts
    3,760
    itll be fine, just do it
    caprice nugget.

  9. #9
    Registered User
    Join Date
    Oct 2009
    Location
    Cuntberra
    Posts
    5,981
    Just run the cunt in reverse polarity and see what happens 90% of DC motors can run reverse polarity when I was a kid all the motors I ever tested which was quite a few were reversible.

    Even my RC boat motor which is brushless is reversible.
    Last edited by Rdyno; 10-05-17 at 07:27 PM.
    Quote Originally Posted by Lord_fahrquhar View Post
    The au put the fucking tunnel in with the bullbar. Even Chuck Norris respects the ability of the au coon.

  10. #10
    Opposed to the PFAD Bill
    Join Date
    Feb 2005
    Location
    Brisbane
    Posts
    9,199
    Just trade it in on something with a working fan.
    Your signature is too long.

  11. #11
    Modulator Southo's Avatar
    Join Date
    Nov 2001
    Location
    Sydney, NSW
    Posts
    7,140
    found a few schematics..





    Red and Blue with white Trace are the two wires - as mentioned by roadsailing - they are quite large due to the current draw..

    Yes, the motor attaches directly to the fan, washer on the botton, nut on top and that's it.
    The motor is wedged firmly into the plastic lower half of the assembly ( see pic above)

    Gammaboy... good point.. I will swap it for a nyloc nut and use loctite..

    I am just concerned about setting the fucking thing on fire.. the nopics drives it most of the time.. and based on previous vehicles, - she is not one to pay close attention when things overheat or start making bad noises...

  12. #12
    Registered User
    Join Date
    Oct 2009
    Location
    Cuntberra
    Posts
    5,981
    Just bench run the motor FFS that will tell you all you need to know if you can't you should buy the right part.
    Quote Originally Posted by Lord_fahrquhar View Post
    The au put the fucking tunnel in with the bullbar. Even Chuck Norris respects the ability of the au coon.

  13. #13
    Registered User
    Join Date
    Sep 2013
    Location
    ....................
    Posts
    5,339
    Quote Originally Posted by Rdyno View Post
    Just bench run the motor FFS that will tell you all you need to know if you can't you should buy the right part.
    Did you read the thread ?
    ......................

  14. #14
    Modulator Southo's Avatar
    Join Date
    Nov 2001
    Location
    Sydney, NSW
    Posts
    7,140
    As someone else mentioned in another forum,........ I am discovering it may not be as easy as first thought...
    A bench test WILL show if it will work or not, sure, - but at 12V flat out - but as this is from the Ti-L model that has the fancy 10 step auto climate control - that may cause issues
    Also, it might be fine running backwards for a few minutes, or even an hour on the bench - but there is apparently an internal cooling fan (supplied air by the tube shown in the 2nd pic above) and if that is directional - then it might overheat if it doesn't get the air into it....... - Why the fuck to things need to be so complicated ???

    I have emailed the seller and see if they can get me the correct one expedited to me. Otherwise I will have either suck it up and pay top dollar for a local one - or get the old one rebuilt with new bearings...

    Thanks for the help...

  15. #15
    Unregistered User Permit Roadsailing's Avatar
    Join Date
    Aug 2003
    Location
    melbourne
    Posts
    5,493
    Quote Originally Posted by Southo View Post
    there is apparently an internal cooling fan (supplied air by the tube shown in the 2nd pic above) and if that is directional - then it might overheat if it doesn't get the air into it.......
    cooling airflow is a function of the impeller and scroll, the outlet of the scroll is high pressure, the inside of the motor is low pressure so air flows, as long as the new motor doesn't block any holes etc. (might run hotter because backwards) the cooling airflow should be OK.

  16. #16
    Modulator Southo's Avatar
    Join Date
    Nov 2001
    Location
    Sydney, NSW
    Posts
    7,140
    Ahh Ok, That makes sense...

  17. #17
    Modulator Southo's Avatar
    Join Date
    Nov 2001
    Location
    Sydney, NSW
    Posts
    7,140
    Ok. So tried the reverse polarity and it ran ok but was much louder and didn't quite spin as fast. So as I need to get the dash back together today (nopics needs the car over the next 3 days) I went to the bearing shop and just bought two new bearings and fitted them to the old motor....

  18. #18
    Compulsive modifier awdmoke's Avatar
    Join Date
    Feb 2011
    Location
    WA
    Posts
    1,145
    Good call.
    Whilst DC motors will run backwards, the brushes are clocked slightly to improve performance in most larger motors. That means they run worse and won't last as long if continually run in reverse.

    Slot cars don't have such wizardry.
    Lots of minis & mokes including a G13b powered Sports Sedan, a couple of Swift Gtis, a Goggomobil, 928S, Polo Gti, BMW 540i, a WRX and a Navara with the deadly ZD30

  19. #19
    Unregistered User Permit Roadsailing's Avatar
    Join Date
    Aug 2003
    Location
    melbourne
    Posts
    5,493
    Quote Originally Posted by awdmoke View Post
    Good call.
    Whilst DC motors will run backwards, the brushes are clocked slightly to improve performance in most larger motors. That means they run worse and won't last as long if continually run in reverse.

    Slot cars don't have such wizardry.
    I think they do and there are gains to be had, but whenever someone starts talking about slot cars on more than a casual level I back away slowly and leave the room so not 100%.

    unusual to have such a quick resolution on PF, or is that only certain members?
    Last edited by Roadsailing; 11-05-17 at 03:02 PM.

  20. #20
    Modulator Southo's Avatar
    Join Date
    Nov 2001
    Location
    Sydney, NSW
    Posts
    7,140
    Fitted the new bearings and reassembled the motor/fan and all the dashboard and it seems to be working well.. It still has a slight noise (but nowhere near as bad as before) - so it will have to do for now until I either get another from Ali-Express or get one locally...

    side note - Why the fuck do they make these things so fucking awkward and cumbersome to remove.... even the service manual says something along the lines of "there are 9 clips to remove, but don;t worry if you break them - just replace them with screws (part # XXXXXXXX) instead....) Need to be a bloody contortionist to get under the dash with a torch and a mirror and 40cm long screwdriver to get to the screws....



    left is the flogged out top bush
    middile is the replacement type bush
    Right is the bearing that is the best fix.. I did the bearings

  21. #21
    Ellis Juan mizone's Avatar
    Join Date
    Jul 2003
    Location
    Western Australia
    Posts
    3,522
    Quote Originally Posted by Rdyno View Post
    Just run the cunt in reverse polarity and see what happens 90% of DC motors can run reverse polarity when I was a kid all the motors I ever tested which was quite a few were reversible..
    Yep this.

  22. #22
    Modulator Southo's Avatar
    Join Date
    Nov 2001
    Location
    Sydney, NSW
    Posts
    7,140
    Quote Originally Posted by mizone View Post
    Yep this.
    I guess you missed the part where I said this didn't work

  23. #23
    Registered User
    Join Date
    Sep 2010
    Location
    Adelaide, SA
    Posts
    1,386
    Quote Originally Posted by Southo View Post

    side note - Why the fuck do they make these things so fucking awkward and cumbersome to remove.... even the service manual says something along the lines of "there are 9 clips to remove, but don;t worry if you break them - just replace them with screws (part # XXXXXXXX) instead....) Need to be a bloody contortionist to get under the dash with a torch and a mirror and 40cm long screwdriver to get to the screws....
    You want to have a go at the HVAC fan on an L322 Rangie. Book time is something like 15 plus hours with an A/C regas required. I can do it in a couple of hours with the use of a hacksaw blade to cut down through the top of the dash (trim hides the hole when reassembled).

  24. #24
    Modulator Southo's Avatar
    Join Date
    Nov 2001
    Location
    Sydney, NSW
    Posts
    7,140
    Quote Originally Posted by BigJonWB View Post
    You want to have a go at the HVAC fan on an L322 Rangie. Book time is something like 15 plus hours with an A/C regas required. I can do it in a couple of hours with the use of a hacksaw blade to cut down through the top of the dash (trim hides the hole when reassembled).
    Yeah, Nah - Fuck that..

    Nissan Stealerships quote around $600 to $700 to do this job. - So assuming about 2.5-3 hrs based on the approx $300 part cost...

    On a side note - had the X-Trail in at the local stealership this week to have the Takata Airbag recall done
    I assume they just get the 1st year apprentice to do it as he busted the glove box clips (and conveniently failed to tell anyone) - so when I had to remove the glove box the day after - I saw it was broken. Called them up and spoke to the Service Advisor, (Cool Bloke) he said bring it down and show them. - He took one look and went - Ahh yeah.. sorry about that - I'll kick his arse and order you a new glove box...
    He said apparently it's a common thing and they "always" break when doing the airbag and he should have said something as Nissan will replace it....

    Funny that I had removed and replaced the Glovebox at least 3 or 4 times in the last month to run power cables, change HVAC motor, replace cabin filter etc and managed not to break it....

  25. #25
    Compulsive modifier awdmoke's Avatar
    Join Date
    Feb 2011
    Location
    WA
    Posts
    1,145
    Yes but try doing it when you are young, stupid, paid $6/he and don't give a fuck.
    Lucky that you picked it the next day.
    Lots of minis & mokes including a G13b powered Sports Sedan, a couple of Swift Gtis, a Goggomobil, 928S, Polo Gti, BMW 540i, a WRX and a Navara with the deadly ZD30

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •