Defrost fan rehab and rebuild thread (fresh air fan), or How the heck do if fix this thing? |
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Defrost fan rehab and rebuild thread (fresh air fan), or How the heck do if fix this thing? |
DRPHIL914 |
Jan 21 2021, 08:55 AM
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#1
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Dr. Phil Group: Members Posts: 5,766 Joined: 9-December 09 From: Bluffton, SC Member No.: 11,106 Region Association: South East States |
I have been dealing with this for 12 years, a non-running defrost fan. i even pulled this out 2 years ago and rebuilt it with new flapper seals and main body seal then made sure fan turned but didnt bench test the motor or resisitors, so as a result it still does not work properly. i will be documenting this because 914rubber and Mark will soon be putting together a kit for this that includes all the hardware seals and even a motor i believe, BUT i still have problems and questions!!! so i am starting this thread to get information on diagnosing the common causes of it not working and how to fix it, and then document the rebuild and replacement of the motor, fan, resistor and maybe the control unit in dash. Others have documented the reinstallation of the fan and the cables so i will not duplicate that. and we may want to link other threads hear that have done that as well.
Mark is sending me a kit soon, so while i wait for it, i will have to get some more information about the wiring and resistors function and how to test them . I had this out last week and tested 3 different control units due to thinking that my issue was a control issue, because it runs on one speed, #2, and anything else does not work and it will then throw the fuse. most assume this would be caused by bad slider unit but i tested 3 of them and 2 are like new with no wear on the sliders , still same result. so i am suspecting the resistors /plug aparatus . If anyone has done this and cares to share how to examine and test that for proper function, lets start there. Resistor function, which lead is which and examination of the control units I will take pictures of mine tonight and post those soon. once this figured out and fixed i will do a full step bystep on reassembly too. Looking for lots of help and input on this, thanks!!! Dr. Phil |
DRPHIL914 |
Mar 25 2021, 06:52 AM
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#2
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Dr. Phil Group: Members Posts: 5,766 Joined: 9-December 09 From: Bluffton, SC Member No.: 11,106 Region Association: South East States |
ok update from trouble shooting last night,
after getting into this and finding i still could only get one speed on the fan, @Superhawk996 reached out to me and he suggested a few other things to check before moving forward, so i wanted to eliminate the medium and high speed wires as being the issue by testing them for continuity. Right now i do have the low speed working, the white/green wire. both the white(medium) and the white/yellow(high) both test same resistance, 2.8-3.0 ohms same as the one that does work , so that seems to eliminate the wires as the issue. i also ran a long jumper wire from the controller/sliders on each of those ground connections so with a new wire i get same result. which also in another way rules out the wires, and i have also hooked up 2 separate control mechanisms to rule that out and same issue there same result. this leaves me thinking i am back to considering the resistor pack as the issue. now when i had the unit out for restoration and installation of the new fan and seals we tested the resistance of those and they seem to have passed the test being at the correct ohm readings but maybe not. so--- i am going to look for a second resistor pack , if anyone had one that has bench tested please let me know, but until then i have 2 choices, one is just leave this in like it is and deal with it- hey i have one speed, a new fan that does work, but not on all 3 speeds, its just frustrating i cant get this 100% working. i am about to just say screw it. - i am probably saying this due to being up until 2:30 am this morning doing this and then trying to get the f-ing box back into place- now the mounting screw on left side stripped out. - way too tight on the seal fit- @Mikey914 this seal needs to be snug but not this tight, about 2mm less thick would help a lot in not having to use an f-ing crow bar to get the box squeezed up into place and bolted in...... |
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