Heat and A/C work, but fan doesn't. Blower motor fuse blown/exploded. Please help.
#1
Heat and A/C work, but fan doesn't. Blower motor fuse blown/exploded. Please help.
I couldn't find any information on this particular problem. My heat and air work and I can feel it coming through at highway speeds, but the fan doesn't blow it into the cabin, so the dial for fan speed does nothing. I checked the fuses and the fuse for the "blower motor" appears to have had a pretty violent explosion. A new fuse won't even go in the slot because some of the bits are still in there from the old one. Is this as simple as replacing this fuse, or does this indicate a serious problem? I'd rather not have to go to a shop for this if I don't absolutely have to. Any useful information on what I should do or what part(s) may need replacing would be greatly appreciated. Thanks.
Pics of the old fuse and its slot are attached.
Pics of the old fuse and its slot are attached.
#2
MBWorld Fanatic!
Joined: Jun 2002
Posts: 6,924
Likes: 123
From: So. Oregon Coast
C230 Sport Coup + 2006 W164 ML350 + 99 Ford Escort (What the heck, it gets 38 mpg!)
Not sure about useful info but this happened to me also,
Though mine was not quite so catastrophic.
It did get a bit melty but not to the point of effecting the actual fuse box.
If you search the EPC you may find a repair kit.
I would try a lower Amperage fuse just to see if it works.
40A is a lot of current. Perhaps a 30A would be better and replace it more frequently without melting stuff.
I'm guessing your fuse was defective or you had the wrong fuse.
Though mine was not quite so catastrophic.
It did get a bit melty but not to the point of effecting the actual fuse box.
If you search the EPC you may find a repair kit.
I would try a lower Amperage fuse just to see if it works.
40A is a lot of current. Perhaps a 30A would be better and replace it more frequently without melting stuff.
I'm guessing your fuse was defective or you had the wrong fuse.
#3
Member
Joined: Dec 2007
Posts: 79
Likes: 0
From: Richmond Hill, Ontario, Canada
MB 2008 C300 sport, 2008 Rally blue Subaru Impreza 2.5 SI 1995 MB C280 W202
I couldn't find any information on this particular problem. My heat and air work and I can feel it coming through at highway speeds, but the fan doesn't blow it into the cabin, so the dial for fan speed does nothing. I checked the fuses and the fuse for the "blower motor" appears to have had a pretty violent explosion. A new fuse won't even go in the slot because some of the bits are still in there from the old one. Is this as simple as replacing this fuse, or does this indicate a serious problem? I'd rather not have to go to a shop for this if I don't absolutely have to. Any useful information on what I should do or what part(s) may need replacing would be greatly appreciated. Thanks.
Pics of the old fuse and its slot are attached.
Pics of the old fuse and its slot are attached.
the blower fan will fail and I just replaced mine yesterday. same issue but the fuse is good on my end.
#4
I couldn't find any information on this particular problem. My heat and air work and I can feel it coming through at highway speeds, but the fan doesn't blow it into the cabin, so the dial for fan speed does nothing. I checked the fuses and the fuse for the "blower motor" appears to have had a pretty violent explosion. A new fuse won't even go in the slot because some of the bits are still in there from the old one. Is this as simple as replacing this fuse, or does this indicate a serious problem? I'd rather not have to go to a shop for this if I don't absolutely have to. Any useful information on what I should do or what part(s) may need replacing would be greatly appreciated. Thanks.
Pics of the old fuse and its slot are attached.
Pics of the old fuse and its slot are attached.
#5
I'm having the exact same problem with my daughters 04 C 240. I pulled the blower motor and blew it out with my air compressor like some other threads suggested but when i reinstalled and had her turn the blower on the fuse and wire got extremely hot again within a couple minutes. I have the fuse pulled right now because I'm afraid it might start a fire if left installed. Has anybody found what is causing it to get so hot?
#6
It's ohms law. The cirucit is shorted causing more current to be drawn than the fuse is rated for. It's common for motors to short internally. You probably just need a new blower motor.
#7
Well, ordered and installed a brand new blower motor. The power wire was so hot within just a few seconds that you couldn't hardly touch it. I was hoping you were right about the motor. The only thing left in that circuit is the resistor. My understanding it's working correctly if its changing the speeds of the motor, which mine does. Any thoughts???
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#9
The blower motors and resistors on these cars seem to fail prematurely. My blower motor was only intermittently working, so I replaced the whole blower motor with resistor. Bought a used one on email for $70. Install is extremely easy. Dealers charge upwards of $500 for this job, so beware.
#10
#11
Blower fuse heats up
I've had the same problem. That blower fuse got so hot it started a fire, luckily I was in garage and was able to put it out. It only heats up when fan control switch is on high speed. Replaced relay in the blower housing and it did not solve the problem. Hooked blower up directly to 12 volts on the bench and it ran fine. No wires heated up. Could the fan speed control switch possibly cause this? Is there a wiring diagram available. Any help would be appreciated.
#13
I'm having the exact same problem with my daughters 04 C 240. I pulled the blower motor and blew it out with my air compressor like some other threads suggested but when i reinstalled and had her turn the blower on the fuse and wire got extremely hot again within a couple minutes. I have the fuse pulled right now because I'm afraid it might start a fire if left installed. Has anybody found what is causing it to get so hot?
For those that replaced the Resistor and Blower Motor, did you ever resolve the issue of the wiring getting hot? Did you have any further issues after replacing parts?
Does anybody have any guidance on replacing the fuse box?
Are you able to use an empty slot in the existing fuse box for the 40A Blower Motor Fuse? Any possibility installing an inline fuse holder for the Blower Motor Fuse?
Thanks in advance for the assistance/guidance!!
Last edited by grace4autos; 07-11-2021 at 11:20 PM.
#14
Blower on my SL 350 not blowing
Control panel illumination comes and goes?
Fuses checked by indy and all OK
Rear window element working!
Looks like its going to have to be a strip out to try and find the problem starting with a blower/resistor strip and replace.
Control panel illumination comes and goes?
Fuses checked by indy and all OK
Rear window element working!
Looks like its going to have to be a strip out to try and find the problem starting with a blower/resistor strip and replace.
#15
This is basic electrical. Heat will only occur where there is a voltage drop. The problem is because the fuse contact is not capable of carrying the high current continuously when the blower is at full speed. My solution would be to make sure the terminals have very good contact at the fuses and also split the current between 2 fuses in parallel.
then fit 2 x 20amp fuses
then fit 2 x 20amp fuses
#16
What fuse box is that?
My blower fan is not doing anything. All the lights on just not blowing anything. I'm trying to change the fuse just need to know which fuse box to look in and which number fuse.
#17
Did you fix the problem?
I have the same problem, I even have jumped with a wire the activation dual fans relay and still heat it up the wires.