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heater won't work in '91 325i convertible

Posted by 325ibimmergirl 
A couple of weeks ago, I noticed that my heater would make a LOUD buzzing sound if I had it on level 2, 3 or 4 (whether it was on the vent, my face or feet). Now after running it like crazy, the heat won't work at all! This is treacherous seeing how winter is closing in on us, and now I have to scrape my car in the morning.

I checked Fuse 20, and its a 30amp fuse that still looks good. What on Earth could this be?! I also have heard/read that the K7 relay could be the problem. I have not checked that yet... but I am really under the impression the heater is biffed.

Any advice?! I am willing to work on the car myself, even though as you can see by my username, I am a girl! ha. I also don't have the actual manual for my car, so if you happen to know a site where I can retrieve that, that would help tremendously as well.

Thanks!!
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325ibimmergirl
A couple of weeks ago, I noticed that my heater would make a LOUD buzzing sound if I had it on level 2, 3 or 4 (whether it was on the vent, my face or feet). Now after running it like crazy, the heat won't work at all! This is treacherous seeing how winter is closing in on us, and now I have to scrape my car in the morning.

I checked Fuse 20, and its a 30amp fuse that still looks good. What on Earth could this be?! I also have heard/read that the K7 relay could be the problem. I have not checked that yet... but I am really under the impression the heater is biffed.

Any advice?! I am willing to work on the car myself, even though as you can see by my username, I am a girl! ha. I also don't have the actual manual for my car, so if you happen to know a site where I can retrieve that, that would help tremendously as well.

Thanks!!

Hello and welcome to BEN :rally:

You can find the wiring diagrams here...[shark.armchair.mb.ca]
It is under the sticky 'Technical and DIY Links' near the top of the page.

I think there may be shop manuals there as well but I will check to see if they aren't.

Should your electrics turn out to be ok, then a common problem is the bushings/bearings on the fan motor. The factory lube eventually dries up and the fan begins to make horrible noises. I had mine relubed and it was still working fine a year later but others have had little success with this. The one solution is to replace the bushings/bearings but at this age, the fan blades have become very brittle and usually break from handling. Once the blades break, the whole fand goes out of balance and then it is jink.
The ultimate solution is to replace the complete blower but that is expensive sad smiley
The symptoms sound like the motor bearings for sure. A replacement motor from salvage is probably the best bet and cost should be about $20 or so. They are not difficult to change. There is a panel under the hood on the fire wall that allows access directly. There is an off chance that some debris has worked its way into the fan and jammed it but Peter is right about the bearings going bad. I could not figure out how to disassemble the motor to change the bearings. It had what appeared to be welded construction.

Bob in Everett
rkj
Cool, our second girl!

Welcome Lady, where are you from? (generally speaking) Cheers, Rick

Is there any smell from the plenum (if the motor was burning out). If the motor was making noise on 2, 3, 4, what was it doing on 1?

You should still have heat even if the motor is going bad, at speed.

Again, welcome aboard and lets see a picture or two smileys with beer
Probably the motor is just stuck on 1
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rkj
Cool, our second girl!

Welcome Lady, where are you from? (generally speaking) Cheers, Rick

Is there any smell from the plenum (if the motor was burning out). If the motor was making noise on 2, 3, 4, what was it doing on 1?

You should still have heat even if the motor is going bad, at speed.

Again, welcome aboard and lets see a picture or two smileys with beer

Welcome 325ibimmergirl!

Check the fuses and relays first before starting to pull things apart.
If it turns out to be the motor, try to clean the ducts and plenum, you will be glad you did so afterwards...
Much better that the little pine tree hanging from the mirror.
And people her enjoy picturs, if you can post some we will be very happy!

JP
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325ibimmergirl
A couple of weeks ago, I noticed that my heater would make a LOUD buzzing sound if I had it on level 2, 3 or 4 (whether it was on the vent, my face or feet). Now after running it like crazy, the heat won't work at all!
Could it be something as simple as a leaf or a twig stuck in the blower fan?


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lets see a picture or two
By the way, we're a (mostly) civilized bunch here, unlike the crowd over on R3Vlimited.com. Over there a request for photos would almost certainly mean nekkid photos of you. Over here though I'm pretty sure they meant photos of your car. :popcorn:
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Ferdinand
Could it be something as simple as a leaf or a twig stuck in the blower fan?
...Cleaning and lubing can't hurt...

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Ferdinand
By the way, we're a (mostly) civilized bunch here, unlike the crowd over on R3Vlimited.com. Over there a request for photos would almost certainly mean nekkid photos of you. Over here though I'm pretty sure they meant photos of your car. :popcorn:

Man, don't know why you brought this up...:stickpoke:
Of course I meant pictures of the car, with our without the owner...
No wonder why there are so few ladies posting here!
hot smiley
Thanks guys for the input. I figured out for sure its NOT the K7 relay. I tinkered a bit with the car from the vents that are outside, below the windshield. I could see the fan from the passenger side vent (once I removed the vent cover), and sprayed it with some WD40. I moved the fan blades, and once I started up the car, the heat was working - but making that LOUD, terrible sound again. So now the heat has been working intermittently. Is there an easy way to get to the fan through the middle vents (that blow on your face) from the inside of the car? There doesn't seem to be an easy way to get into the blower/fan from the engine, unless I'm mistaken...?

Sorry, I don't know proper/technical terms for the things in my car. ha

Thanks fellas!
To get at the fan you have to go through the back of the engine compartment. There is a panel centred on the firewall, behind the engine. Just lift up the rubber hood seal along the rear edge of the engine compartment, then you might have to undo two plastic nuts that hold a cable bracket crossing behind the engine, then four(?) screws hold the panel in place.

With that panel removed you can see into the area where the blower fan and the windshield wiper motor sit.
The most important accessory for your car is the Bently publishing service manual for the E-30 model. It costs about $40 but will save the cost the first time you have to solve a problem.
[www.amazon.com]

Bob in Everett
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Bob in Everett
The most important accessory for your car is the Bently publishing service manual for the E-30 model. It costs about $40 but will save the cost the first time you have to solve a problem.
[www.amazon.com]

Absolutely...I save thousands of dollars on unnecessary repairs because I had that manual and could tell if a mechanic was trying to snow me.
Sadly, I gave mine away to the lucky fellow who bought my iX sad smiley
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Ferdinand
To get at the fan you have to go through the back of the engine compartment...

There are some photos in these threads:

[www.r3vlimited.com]
[www.r3vlimited.com]
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