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Al, BMW Technician
Category: BMW
Satisfied Customers: 69
Experience:  BMW Master Technician,ASE Master Technician,24 Years BMW Experience,Virginia State Inspector
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1990 325i: heater wont work..blower motor

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My 1990 325i C heater won't work. I've tested the blower motor and it seems fine. I replaced the blower motor resistor and it worked great for about an hour as I was driving around town. When I got back into my car and turned it on the heater stopped blowing again. What do I do next? I bought the blower switch part but didn't replace the old one because it seemed to work fine after I put in the new resistor. My dad says it looks like this new resistor has blown out too. Do you have any ideas for me? I really am not intrested in taking it in unless I absolutly have to. I have the eans to fix it here. I am just out of ideas.
Hello Karen,is the blower motor making any abnormal noise?Did it blow the fuse when it stopped working after the resistor?
Customer: replied 8 years ago.
it's not making any noise. the fuses were never blown out, I just replaced them hoping it would help.
Hello Karen,the next thing I would do is remove the cover from the cowl and turn the blower on and then take a scewdriver and give the blower a little push at the blower cages and see if it starts working.If the blower starts working then youhave a bad blower motor,ie;brushes worn out or armature bad.Please let me know if htis works or if you need more help,Thanks Al.
Customer: replied 8 years ago.
I am sorry I didn't mention that I did do that this afternoon after I got home. that didn't work so I took out the new resistor to look at it and that is when my dad said it looked like the resistor had burnt out again. why does the resistor keep burning out?
Hello Karen,did you try the blower with it on 4 blower speed as this bypasses the resistor?
Customer: replied 8 years ago.
yes, all settings are not working. before I replaced the resistor I got it to work on 4 for a minute and then it stopped working totally. then when I put the new resistor in it worked on all speeds for a bit, but not at all now.
Ok Karen,the next thing I would is try jumping power to the positive side of the motor and see if it runs.By the way do you have a test light or volt meter to check for power at the blower motor with it in posotion 4?
Customer: replied 8 years ago.
do you mean hook up the blower motor to the battery to see if it spins? because that was the very first thing I did. or do you mean while its still in the car? I guess there is something here to check it in pos. 4.
First if you have a test light check for power at the blower motor with the wires disconnected from the motor.Then check for ground by attaching the clamp end of the test light to the battery cable that is at the passenger side of the cowl and toching the ground wire of the blower motor and see if the light lights up.If you have power and ground in position 4 then the blower motor is bad and burning your resistor up.Thanks Al.
Customer: replied 8 years ago.
what if it doesn't work in 4?
If it does not work in position 4 and you have power and ground at the blower motor then the blower is bad.If you do not have power and ground at the fan then the blower switch is bad.I will check this in more detail tomorrow if you would like and get back to you with wire colors at switch so you can test the switch.
Al and other BMW Specialists are ready to help you
Customer: replied 8 years ago.
i would really appriciate that. but, will you just email me that? do I pay now or later? lol I appriciate your help.
Your personal email will be blocked on this site so we will have to work through the site.You don't have to pay until we find and resolve your problem or you can pay and still work on the problem.I would rather you pay when we fix your problem and if you don't have a test light you can pick one up at a parts store cheap.Thanks Al.
Karen ,remember we can still work on this question without you having to pay again and positive feedback would be greatly appreciated.Thanks Al.
Customer: replied 8 years ago.
I payed already. I guessed the wrong answer. How do I find you again tommarrow, is my next question. I gotta get off line now though.
Hello Karen,there is a tab you can use to ask for a specific expert.Your power supply to the blower switch is the green and brown wire and theground is the brown wire.I forgot the electrical manual but I think the blue wire is the power to the blower motor when in position 4.Thanks Al.