Defrost fan rehab and rebuild thread (fresh air fan), or How the heck do if fix this thing? Options

[DRPHIL914]

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]

@Mikey914
@Superhawk996

for superhawk, update on my 2 fans with testing the resistor packs, with new leads and cleaning contacts etc i get same readings for both of these, low medium and high are at or close to normal range. I think both are good, so i will assemble each in a cleaned up housing with new seals, one will hvae my brand new fan from URO and the other will have the new used one that tests good from Al Merideth, good free turning fan i bench tested it yesterday.

But @Mikey914 no care package no seal or rebuild kit has arrived, this project is stopped until i get the seals from 914rubber.

Mark, i will buy 2 additional kits too with all the seals including the new big fan to housing seal and the flappers seals and lower to upper housing seals., along with hardware.

If you can have the staff email me a paypal invoice i would like this sent out asap. thanks,

Phil

[Superhawk996]

@Mikey914


for superhawk, update on my 2 fans with testing the resistor packs, with new leads and cleaning contacts etc i get same readings for both of these, low medium and high are at or close to normal range. I think both are good,

@DrPhil914

If you're getting similar readings between Medium and High Speeds, I'm thinking that your DMM is having resolution issues at very low ohm readings.

Might be time to upgrade the DMM. I'm always a fan of Fluke but let's be honest, that is big money for a hobby meter.

I've used HF meters with good sucess - not pro grade but not bad for hobby use. I consider them to be "burner" DMM's. I prefer the newer AMES unit.

https://www.harborfreight.com/dm1010-profes...eter-64021.html

I also have one of these around and found it to be OK but is sometimes a bit glitchy if you just turn it on and fly right to ohms settings. It sort of locks up intermittently. If you switch on, wait and then go to ohms, it's fine.

https://www.harborfreight.com/5-in-1-digita...eter-98674.html

I was maybe going to recommend an old school analog Pro grade meter but OMG . . . prices have gone way up. Price is now comparable to cost for a Fluke DMM.

https://www.grainger.com/product/1A587?cm_m...ASABEgKdKvD_BwE

Gold Standard Fluke

https://www.mscdirect.com/browse/tnpla/5243...BSABEgLxmfD_BwE

[DRPHIL914]

@Mikey914


for superhawk, update on my 2 fans with testing the resistor packs, with new leads and cleaning contacts etc i get same readings for both of these, low medium and high are at or close to normal range. I think both are good,

@DrPhil914

If you're getting similar readings between Medium and High Speeds, I'm thinking that your DMM is having resolution issues at very low ohm readings.

Might be time to upgrade the DMM. I'm always a fan of Fluke but let's be honest, that is big money for a hobby meter.

I've used HF meters with good sucess - not pro grade but not bad for hobby use. I consider them to be "burner" DMM's. I prefer the newer AMES unit.

https://www.harborfreight.com/dm1010-profes...eter-64021.html

I also have one of these around and found it to be OK but is sometimes a bit glitchy if you just turn it on and fly right to ohms settings. It sort of locks up intermittently. If you switch on, wait and then go to ohms, it's fine.

https://www.harborfreight.com/5-in-1-digita...eter-98674.html

I was maybe going to recommend an old school analog Pro grade meter but OMG . . . prices have gone way up. Price is now comparable to cost for a Fluke DMM.

https://www.grainger.com/product/1A587?cm_m...ASABEgKdKvD_BwE

Gold Standard Fluke

https://www.mscdirect.com/browse/tnpla/5243...BSABEgLxmfD_BwE

thanks for the recommendations, i will invest in a good one, i had a much better meter but it took a crap last year , need a good one with a good warranty