Hi all. To anyone who's been on this site for more than 2 days, you have probably seen a post about the blower motor resistor going bad (fan only works on 2 highest speeds...etc). I am going to try to come up with a fix for this problem that does not involve spending $25 at the dealer. Since there are so many people with this problem, even if it saves $10 it'll be worth it, and I think I can do it for under $5.
What I need to know is the resistances of resistor pack when it is in full working order. I believe there are 2 "channels" of resistance in the resistor pack (you can see the pack and the 2 channels <a href=http://www.j-body.org/forums/read.php?f=11&i=44994&t=44994>here</a>.
It makes sense that there are only 2 channels, even though there are 4 fan speeds: channel 1 is for the lowest speed, channel 2 is for the second speed, combining the resistances of channels 1 and 2 for the thrid speed, and no resistance for full speed. Or something like that...
Anyways, I need to know what the resistances are of the 2 resistor "tracks". If you follow the link above, you'll notice that one track is a lot skinnier than the other. Let's call that "track 1" if you reply to this message with the resistance values. I would measure them myself, but mine is fried (hence why I am doing this project). I am going to school for electrical engineering and may be able to create a simple cheap solution for this problem. Please help me out if you can! Thanks!
P.S. If more than a couple people can reply with the values to validate what others have measured, that would be great! Thanks again.
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I wanna use Flash for my sig but it doesn't work.
<img src=http://www.geocities.com/raydur/sig.gif>
Aoccdrnig to a rscheearch at Cmabrigde Uinervtisy, it deosn't mttaer in waht oredr the ltteers in a wrod are, the olny iprmoetnt tihng is taht the frist and lsat ltteer be at the rghit pclae. The rset can be a total mses and you can sitll raed it wouthit porbelm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe.
Fcuknig amzanig huh?
if you are going to school for electrical, you would obviously know that using resistors would not be the way to go, using a simple potentiometer would be your answer.
Uhh, no. Using a pot would make the fan speed switch on the control panel useless.
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<a href="http://clik.to/theredbowtie"><img src="http://www3.sympatico.ca/theredbowtie/graphics/sig.jpg" border="0" alt="Click here!"></a>
not to mention I am trying to do this as cheap as possible for everyone...
Anyone with those resistance values?
Help a guy out!
<br>
I wanna use Flash for my sig but it doesn't work.
<img src=http://www.geocities.com/raydur/sig.gif>
Aoccdrnig to a rscheearch at Cmabrigde Uinervtisy, it deosn't mttaer in waht oredr the ltteers in a wrod are, the olny iprmoetnt tihng is taht the frist and lsat ltteer be at the rghit pclae. The rset can be a total mses and you can sitll raed it wouthit porbelm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe.
Fcuknig amzanig huh?
I tried to get a reading off my blown resistor board, and either my
multi-meter is messed up, or I suck at using it. Could be both as well.
Even when it was blown it read as though it had zero resistance.
And i farged up my neck (once again aggravated slipped disk) the last
time, so i can't go diving under the dash for a while.
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The readings will probably need to be taken from a board that is in working order. If it is fried, the circuit will not be complete and you won't get a resistance reading. Or at least that is what I think will happen.
Anyone got those values?
<br>
I wanna use Flash for my sig but it doesn't work.
<img src=http://www.geocities.com/raydur/sig.gif>
Aoccdrnig to a rscheearch at Cmabrigde Uinervtisy, it deosn't mttaer in waht oredr the ltteers in a wrod are, the olny iprmoetnt tihng is taht the frist and lsat ltteer be at the rghit pclae. The rset can be a total mses and you can sitll raed it wouthit porbelm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe.
Fcuknig amzanig huh?
go out and buy some resistors, use your math, I over ER
None of the manuals I can dig up show what the resistance should be. There's either power or there's not. The resistors themselves will be easy if you can read the colour codes, the the values of the PCB traces, I couldn't say.
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<a href="http://clik.to/theredbowtie"><img src="http://www3.sympatico.ca/theredbowtie/graphics/sig.jpg" border="0" alt="Click here!"></a>
Uh, I plan on going out to buy some resistors, but I need to know which resistors to get... That's the whole point...
RedBowtie: Are you referring to the colors on the resistors I'm going to replace the circuit with? I do know how to read those. I'm not sure what you mean if you are talking about colors on the PCB traces...
<br>
I wanna use Flash for my sig but it doesn't work.
<img src=http://www.geocities.com/raydur/sig.gif>
Aoccdrnig to a rscheearch at Cmabrigde Uinervtisy, it deosn't mttaer in waht oredr the ltteers in a wrod are, the olny iprmoetnt tihng is taht the frist and lsat ltteer be at the rghit pclae. The rset can be a total mses and you can sitll raed it wouthit porbelm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe.
Fcuknig amzanig huh?
bump
<br>
I wanna use Flash for my sig but it doesn't work.
<img src=http://www.geocities.com/raydur/sig.gif>
Aoccdrnig to a rscheearch at Cmabrigde Uinervtisy, it deosn't mttaer in waht oredr the ltteers in a wrod are, the olny iprmoetnt tihng is taht the frist and lsat ltteer be at the rghit pclae. The rset can be a total mses and you can sitll raed it wouthit porbelm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe.
Fcuknig amzanig huh?
You won't find any readings with a meter. The circuit board traces are a resistive film technology. They will read 0 until current passes through where they will warm up and rise in resistance to what’s appropriate. Looking into the connector with the lock tab up the pins are (from left to right) A B C D. For the schematic look in a factory service manual or maybe the other books. I'll try to attach to but can't promise anything.
The circuit works like this. Blower switch connects position 4 directly to +12 on high. Blower Resistor Pin C is +12, Pin C to B is switch position 3 (medium 2), Pin C to B to A is switch position 2 (medium 1) and pin C to B to A to D is switch position 1 (low - always on). As you can see the series resistances add up and the fan speed is slower for each step or position of the fan switch and, with position 1 being on all the time (all parts of the circuit in use) the circuit is always warm. That’s why it's inserted into the air path for cooling.
Now for a possible fix: use a jumper wire and try to solder across the burned open part. Not sure if that’s possible as the resistive element may not be solderable. Conductive epoxy may work though. I have to replace one this week so I will have something to experiment with and will keep you posted.
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- Attachments
- Blower Resistor2.gif (139k)
Blind Julius
<img src="http://www.toontracker.com/magoo/mrmagoo1.jpg" width=200 height=130>
"Oh! My My!" Splat . . . "Damn Squirrel ! ! !"
Hey . . . the attachment thingy works! ! ! ! Way cool Mr. Dave! hehe <br>
Blind Julius
<img src="http://www.toontracker.com/magoo/mrmagoo1.jpg" width=200 height=130>
"Oh! My My!" Splat . . . "Damn Squirrel ! ! !"
Well, I'm sure the attachment thingy works good for you, but it doesn't work for us lowly non-premium members...
Any chance on posting again so the rest of us can see?
Or can someone premium please grab that picture and post it again the normal way?
By the way, thanks for the info on how the switches work. I figured it was something like that, but wasn't sure in what order...
Thanks again.
<br>
I wanna use Flash for my sig but it doesn't work.
<img src=http://www.geocities.com/raydur/sig.gif>
Aoccdrnig to a rscheearch at Cmabrigde Uinervtisy, it deosn't mttaer in waht oredr the ltteers in a wrod are, the olny iprmoetnt tihng is taht the frist and lsat ltteer be at the rghit pclae. The rset can be a total mses and you can sitll raed it wouthit porbelm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe.
Fcuknig amzanig huh?
The image is scanned and in .gif format at 139K. I don't know how to add it to a post in the "normal" way (I've never been known for being normal anyway- sorry) so I put it on as an attachment. Tell me how and I will do it. <br>
Blind Julius
<img src="http://www.toontracker.com/magoo/mrmagoo1.jpg" width=200 height=130>
"Oh! My My!" Splat . . . "Damn Squirrel ! ! !"
How's this:
<img src="http://registry.gmenthusiast.com/images/blindjulius/Blower%20Resistor.gif" width=400 height=700>
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Blind Julius
<img src="http://www.toontracker.com/magoo/mrmagoo1.jpg" width=200 height=130>
"Oh! My My!" Splat . . . "Damn Squirrel ! ! !"
That definately helps. Thanks!
OK, so the resistance of the tracks may not be able to be measured by normal means, but there must still be a resistance that they "get to". Any to determine what this resistance should be?
<br>
I wanna use Flash for my sig but it doesn't work.
<img src=http://www.geocities.com/raydur/sig.gif>
Aoccdrnig to a rscheearch at Cmabrigde Uinervtisy, it deosn't mttaer in waht oredr the ltteers in a wrod are, the olny iprmoetnt tihng is taht the frist and lsat ltteer be at the rghit pclae. The rset can be a total mses and you can sitll raed it wouthit porbelm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe.
Fcuknig amzanig huh?
I did some quick calculations and found the values are something like 0.1 Ohm and 50W for each of the resistances on the board. Not something you'll get at Radio Shack. Also note the patent number printed on the side. Might be a good reason for that.
Now for a bit of good news. I've been able to get conductivity by soldering a piece of desoldering braid (Radio Shack) across the burned out part. Don't know if it'll work correctly as of yet. I used an x-acto knife to carefully scrape the coating off. Be careful not to get solder across any of the other parts. Here's a pic:
<img src="http://registry.gmenthusiast.com/images/blindjulius/Pdr_0070-1.jpg" width=300 height=630>
<br>
Blind Julius
<img src="http://www.toontracker.com/magoo/mrmagoo1.jpg" width=200 height=130>
"Oh! My My!" Splat . . . "Damn Squirrel ! ! !"
.1 ohm? that seems pretty low, but maybe it has to do with the "technology" (for lack of a better word) that they are using. If it's a 12V original source voltage, it would have to be much more resistance than that to reduce the current enough to make the fan decrease in speed by any significant amount. How did you calculate these values? And what do you mean by 50W?
If it was warmer here, I'ld crawl up in and be doing all this myself, but I don't have a garage, so I'm not going to sit in a 15 degree car and do all this. So, thanks, I appreciate it.
<br>
I wanna use Flash for my sig but it doesn't work.
<img src=http://www.geocities.com/raydur/sig.gif>
Aoccdrnig to a rscheearch at Cmabrigde Uinervtisy, it deosn't mttaer in waht oredr the ltteers in a wrod are, the olny iprmoetnt tihng is taht the frist and lsat ltteer be at the rghit pclae. The rset can be a total mses and you can sitll raed it wouthit porbelm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe.
Fcuknig amzanig huh?
Boy, you're gonna put me through this huh?
Since there's a 30A fuse I'll figure that's the current in the circuit. Current in a series circuit is the same in all the legs. I figured for motor voltages of 12V for high, 10V for med 2, 7V for med 1 and 5V for low. In med 2 the voltage drop across the resistor is 2V. R = E / I so pluging in numbers I get R = 2 / 30 and the answer is .06666666> so I rounded it up to .1 Ohm. Then figuring for watts P = E x I and pluging in numbers P = 2 x 30 and the answer is 60Watts. That's the reason for the large traces on the board. I'll let you do the calculations for the rest of the examples. I might have something screwed up as I really haven't used Ohms Law for awhile and it's 4:00 a.m. here and we haven't heard from any other EE people. <br>
Blind Julius
<img src="http://www.toontracker.com/magoo/mrmagoo1.jpg" width=200 height=130>
"Oh! My My!" Splat . . . "Damn Squirrel ! ! !"
Is there any way to measure the actual voltage drop from each of the settings? I haven't crawled up underneath my dash yet, so I'm not sure how dificult this would be to do, but is it possible to get reading of the voltage drop after the resistor while in use?
I think we're getting close here...
<br>
I wanna use Flash for my sig but it doesn't work.
<img src=http://www.geocities.com/raydur/sig.gif>
Aoccdrnig to a rscheearch at Cmabrigde Uinervtisy, it deosn't mttaer in waht oredr the ltteers in a wrod are, the olny iprmoetnt tihng is taht the frist and lsat ltteer be at the rghit pclae. The rset can be a total mses and you can sitll raed it wouthit porbelm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe.
Fcuknig amzanig huh?
Anything is posible however it wouldn't be practical because of the power rating. When I worked at Northrop-Grumman in Rolling Meadows I was able to get my hands on some used precision 25W 1 Ohm resistors. Don't think you'll be able to find that kind of stuff easily or cheap. Best bet would be to try the repair like I did. I'll try to put it in on Sunday and report how it worked.
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Blind Julius
<img src="http://www.toontracker.com/magoo/mrmagoo1.jpg" width=200 height=130>
"Oh! My My!" Splat . . . "Damn Squirrel ! ! !"
I was thinking about that too - what would be big enough to use for this application. I don't think we would need that big of a resistor - big, but not something capable of 60 watts.
To be honest with you, I'm not familiar with how resistors are rated as far as watts go. But if they are rated in watts, I would think that the rating would be for power dissipation (sp?). In other words, a 25 watt resistor would be able to dissipate 25 watts of power safely. That would be well more than enough for this application, since one resistor would never come close to that much dissipation. Maybe several of them together in series to get the low speed setting, but not individually. So those might work if you can get your hands on them...
<br>
I wanna use Flash for my sig but it doesn't work.
<img src=http://www.geocities.com/raydur/sig.gif>
Aoccdrnig to a rscheearch at Cmabrigde Uinervtisy, it deosn't mttaer in waht oredr the ltteers in a wrod are, the olny iprmoetnt tihng is taht the frist and lsat ltteer be at the rghit pclae. The rset can be a total mses and you can sitll raed it wouthit porbelm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe.
Fcuknig amzanig huh?
Well, you can try anything however if my calculations are correct then that's what Ohm's law says. Trying something smaller may work but there's a chance of something going wrong and starting a fire under the dash. Not what I want to do.
<br>
Blind Julius
<img src="http://registry.gmenthusiast.com/images/blindjulius/personal_pic.jpg" width=200 height=180>
"Oh! My My!" Splat . . . "Damn Squirrel ! ! !"
ahhh, nevermind, I was thinking backwards again....
<br>
I wanna use Flash for my sig but it doesn't work.
<img src=http://www.geocities.com/raydur/sig.gif>
Aoccdrnig to a rscheearch at Cmabrigde Uinervtisy, it deosn't mttaer in waht oredr the ltteers in a wrod are, the olny iprmoetnt tihng is taht the frist and lsat ltteer be at the rghit pclae. The rset can be a total mses and you can sitll raed it wouthit porbelm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe.
Fcuknig amzanig huh?
Any luck with the repaired board?
<br>
I wanna use Flash for my sig but it doesn't work.
<img src=http://www.geocities.com/raydur/sig.gif>
Aoccdrnig to a rscheearch at Cmabrigde Uinervtisy, it deosn't mttaer in waht oredr the ltteers in a wrod are, the olny iprmoetnt tihng is taht the frist and lsat ltteer be at the rghit pclae. The rset can be a total mses and you can sitll raed it wouthit porbelm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe.
Fcuknig amzanig huh?
