E36 30amp blower fuse blown
Discussion
The heater blower stopped working last week just as the temps plummeted.
Spent the weekend driving around fully togged up with gloves on and the windows open. Jeez I was cold.
Stupidly the fuse was not the first thing I checked and having had problems with the heater before, I jumped straight to the conclusion that it was the 'hedgehog' aka final stage resistor.
Boy! that was a bugger to get to and I now have my glovebox and various ducts sitting on the back seat.
New 'cheap' resistor arrived today and I plugged it in but alas no blowing. Very sad as replacing the blower itself is probably beyond me and I have heard horror stories of £600 bills. Thinking it was time for me and my BMW, owned since 1998, to part ways.
Started looking at the fuses after reading that they may be behind the glovebox but could not find them to only find that fuse 20 in the engine bay was well and truly burnt out.
New 30 amp fuse and the old hedgehog fitted and its all working.
Begs the question though, why would the fuse blow anyway???
The new hedgehog still doesn't work btw.
Spent the weekend driving around fully togged up with gloves on and the windows open. Jeez I was cold.
Stupidly the fuse was not the first thing I checked and having had problems with the heater before, I jumped straight to the conclusion that it was the 'hedgehog' aka final stage resistor.
Boy! that was a bugger to get to and I now have my glovebox and various ducts sitting on the back seat.
New 'cheap' resistor arrived today and I plugged it in but alas no blowing. Very sad as replacing the blower itself is probably beyond me and I have heard horror stories of £600 bills. Thinking it was time for me and my BMW, owned since 1998, to part ways.
Started looking at the fuses after reading that they may be behind the glovebox but could not find them to only find that fuse 20 in the engine bay was well and truly burnt out.
New 30 amp fuse and the old hedgehog fitted and its all working.
Begs the question though, why would the fuse blow anyway???
The new hedgehog still doesn't work btw.
Bear in mind that 30 amps at 12v is 360 watts so you've clearly got a significant problem somewhere. Obviously the fuse is there to give you a "fail safe" but you need to be cautious - 360w is a lot of heat if it gets in the wrong place.
If you have access to a high current ammeter you could connect it in series with the fuse and switch things that are on that circuit to see what sort of current drain you're getting.
If you have access to a high current ammeter you could connect it in series with the fuse and switch things that are on that circuit to see what sort of current drain you're getting.
rockin said:
Bear in mind that 30 amps at 12v is 360 watts so you've clearly got a significant problem somewhere. Obviously the fuse is there to give you a "fail safe" but you need to be cautious - 360w is a lot of heat if it gets in the wrong place.
If you have access to a high current ammeter you could connect it in series with the fuse and switch things that are on that circuit to see what sort of current drain you're getting.
Cheers.If you have access to a high current ammeter you could connect it in series with the fuse and switch things that are on that circuit to see what sort of current drain you're getting.
As the fuse itself is over 20 years old, is it possible it just wore out. Clutching at straws here.
So far everything appears to be working.
croyde said:
Blower sounds fine as it's always done.
Is there an easy way to get to look at it?
Blowers are generally buried under the dash and difficult to access. Is there an easy way to get to look at it?
Regrettably, fuses don't just wear out.
The usual issue with blower motors is water ingress - typically caused when drain holes in front of the windscreen get blocked by debris and water overflows into the blower inlet, eventually causing corrosion in the motor. This makes the motor harder to turn and increases its current draw. Often you will find cars where the blower works, but only at full speed. This is because the speed controller uses a "resistor pack" to deliver the lower speeds and those resistors can blow just like a fuse if too much current is put through them. As there's no resistor in the full speed circuit it's able to continue working after the others have failed.
A sticky blower will sound fine, it just draws more current. Once the stickiness causes the current to rise above a specified level the fuse will blow to prevent your loom melting with resultant electrical fire.
croyde said:
Blower sounds fine as it's always done.
Is there an easy way to get to look at it?
You could probably get an endoscope down to it if you tried. Whether you'd be able to glean anything helpful through it is another matter; also you risk damaging other parts of the climate system if you're not careful. Is there an easy way to get to look at it?
rockin said:
Blowers are generally buried under the dash and difficult to access.
Regrettably, fuses don't just wear out.
The usual issue with blower motors is water ingress - typically caused when drain holes in front of the windscreen get blocked by debris and water overflows into the blower inlet, eventually causing corrosion in the motor. This makes the motor harder to turn and increases its current draw. Often you will find cars where the blower works, but only at full speed. This is because the speed controller uses a "resistor pack" to deliver the lower speeds and those resistors can blow just like a fuse if too much current is put through them. As there's no resistor in the full speed circuit it's able to continue working after the others have failed.
Yep. I went through this with my old Focus. Its blower had a non-serviceable bearing which was corroded, which blew one of the resistors. Regrettably, fuses don't just wear out.
The usual issue with blower motors is water ingress - typically caused when drain holes in front of the windscreen get blocked by debris and water overflows into the blower inlet, eventually causing corrosion in the motor. This makes the motor harder to turn and increases its current draw. Often you will find cars where the blower works, but only at full speed. This is because the speed controller uses a "resistor pack" to deliver the lower speeds and those resistors can blow just like a fuse if too much current is put through them. As there's no resistor in the full speed circuit it's able to continue working after the others have failed.
After replacing the resistor, I was able to prolong the bearing's life with occasional injections of GT85 in situ. Not an elegant solution, but a cheap and practical one!
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