demoniality Posted June 17, 2019 Share Posted June 17, 2019 (edited) Radiator fan motors wouldn't work without a tap from a spanner so I refurbed both motor's brushes (stuck) as per guide. Went well in terms of both now starting at 95 degrees coolant and when air con is on. Whether a new development or not, upon re-installation, i found both fans spin anti-clockwise, taking hot engine bay air and pushing it out the front of the car. I thought I had made a wiring mistake but the connector clips wouldn't allow that even if I wanted to. I thought I had mounted the fans incorrectly but base mounts and wiring loom are all correct. What could this possibly be? Edited June 17, 2019 by demoniality Quote Link to comment Share on other sites More sharing options...
Keyser Posted June 18, 2019 Share Posted June 18, 2019 A DC motor will run backwards if the polarity is reversed so the polarity must be reversed, I would guess you put the caps on backwards but I have never actually stripped and refurb'd the fan motors so I don't know that for sure, just seems the only simple thing to reverse the polarity. 2 Quote Link to comment Share on other sites More sharing options...
ZMANALEX Posted June 18, 2019 Share Posted June 18, 2019 Agree with Chris, you have reversed the polarity somehow. Quote Link to comment Share on other sites More sharing options...
demoniality Posted June 20, 2019 Author Share Posted June 20, 2019 Thanks for the quick replies guys. It is a strange one. Further to your comments I've been reading up on the ability to do this to a DC motor and as far as I can tell without changing the polarity by switching POS neg wires or rewinding the coils it shouldn't be possible. To refurb all I did was separate motor, free and sand the brushes, put the motor halves back together in the same alignment as previous! Unlike what appears to be a US version of the fan motors, the input wires are hidden on mine (ours?) by a black shroud so impossible to replace by mistake. Any more ideas from anyone welcome! Quote Link to comment Share on other sites More sharing options...
SHEZZA Posted June 20, 2019 Share Posted June 20, 2019 I’m not sure it’s possible but maybe you’ve crossed the brushes over, when putting it back together as they spring out when taking the motor apart. ? Quote Link to comment Share on other sites More sharing options...
EzeePzee Posted June 20, 2019 Share Posted June 20, 2019 The brushes in the motors shouldn’t have leads long enough to get them in the wrong slot - at least not in my experience. Are the motors and blades definitely mounted in the right way around? Note that 1 fan has 5 blades and the other only 4. Marked A and B. Quote Link to comment Share on other sites More sharing options...
EzeePzee Posted June 20, 2019 Share Posted June 20, 2019 Plus the slots in the brush runners are only on 1 side meaning the lead couldn’t be attached from the wrong side. Can’t see that being likely but as always happy to be proven wrong Quote Link to comment Share on other sites More sharing options...
EzeePzee Posted June 20, 2019 Share Posted June 20, 2019 Bottom two wires (yellow and black) on the connectors are ground. The green and blue wires are positive 12v - one connected is slow speed and both connected is fast speed. Quote Link to comment Share on other sites More sharing options...
demoniality Posted February 5, 2022 Author Share Posted February 5, 2022 For anyone else finding this one day - the cause was that the casing of each side of the motor was not realigned exactly as i took it apart. rotating either side slightly resulted in the motor turning the opposite way. Mark both sides of the motor housing with something before you disassemble so it's easy to align it correctly later. 👍 1 Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.