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 |
Superhawk996 |
Jan 21 2021, 09:43 AM
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#2
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914 Guru Group: Members Posts: 5,815 Joined: 25-August 18 From: Woods of N. Idaho Member No.: 22,428 Region Association: Galt's Gulch |
Not trying to be a jerk here. But I keep seeing a pattern in the forum when people are stuggling with electrical issues.
Rule #1: Don't assume anything Rule #2: You MUST have a schematic and understand how to read and use it. Rule #3: You must have a DMM Rule #4: Learn the 1/2 split method (Google or PM me) Rule #5: You must follow a methodical approach. If you're not already familiar with DC motor theory, spend some time on Google to understand that too. Chasing other people's assumptions of what might be the cause and/or fixes that once worked for so and so will lead you on a path to nowhere. |
DRPHIL914 |
Jan 21 2021, 11:01 AM
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#3
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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 |
Not trying to be a jerk here. But I keep seeing a pattern in the forum when people are stuggling with electrical issues. Rule #1: Don't assume anything Rule #2: You MUST have a schematic and understand how to read and use it. Rule #3: You must have a DMM Rule #4: Learn the 1/2 split method (Google or PM me) Rule #5: You must follow a methodical approach. If you're not already familiar with DC motor theory, spend some time on Google to understand that too. Chasing other people's assumptions of what might be the cause and/or fixes that once worked for so and so will lead you on a path to nowhere. soooo maybe you've missed the main thrust of this , which is to document a rebuild process, but also the trouble shooting and diagnosis of the common causes of failure of this unit., mainly for those with less experience in working with electrical issues. 1- nothing here has been or is assumed 2- i have the schematics on the laminated sheets - most have never had any electronics or wiring classes, i have ha some but many years ago 4 - i always search the forum and google for same or similar topic, and have done so regarding this extensively , only one thread comes up with any explanation of the resistor connections by @beatnavy and that does not really look into testing or replacing the resistors 5- thats the plan regarding my own current situation ive verified power to the source, proper ground, and just a basic trial and error experiment found the change of controllers made no change. so i could have 3 controllers that all have exactly the same issue OR more likely the issue is at the fan and resistors. SO have you sir gone thru this process with this unit? if you have do you have some constructive advice or experience specifically regarding it? if so please post. since i am not an electrician i may also be asking how to interpret the schematic. but yes i agree your list of the above suggestions is not a bad , yes you kind of do come across as a bit of a jerk , sorry, if that is all you are contributing here. with that said i am no rookie here having essentially taken this car apart and put tit back together in the past 12 years, and how did i do that? with a lot of time and energy in research and internet searching and a lot of stupid questions getting valuable answers here on this forum. I would never have started this post if there were already a nice clear concise description on the subject (its not just the electrical issue as i stated in my first post but also to document the rebuild) |
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