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C230K Sport Sedan
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5,368 Posts
Discussion Starter #1
The heater & a/c fan/blower was working fine up until today. Doesn't matter what you set the rotary fan switch to, nothing comes on. When you turn the A/C on you can here it engage so it's not the A/C compressor and the fan doesn't work with A/C or heat.

I tried locating the fuse but there isn't a fuse specifically marked for the HVAC system but a few say tempamatic like 33, 37, etc. but they are all good. Do I have the the right fuse? Also, looking back at posts it says I may have to replace the fan or the switch, how do you get to this fan/blower?
 

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C230K Sport Sedan
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5,368 Posts
Discussion Starter #2
Doing some research I see that the blower motor, the blower motor regulator (resistor?) are the usual suspects and thanks to a good forum in the UK I can see how to remove these but how can I test to see which is causing the problem? There's no noise or smell or bright neon finger pointing me towards anything, just stopped working completely. Any help would be appreciated.
 

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Golf R32 / Prev R170 SLK
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6,821 Posts
Remove kick panel, 2 screw
Remove connector off fan motor
Remove cover under fan
Reconnect and put a volt meter on 2 spade terminals on motor to check for power there with ign on and fan on full
If ok then same as mine, brushes $35
If no volts check input to reg , brown to blue lead

Bazzle
 

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C230K Sport Sedan
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5,368 Posts
Discussion Starter #4
It started working again all by itself. Does that mean the motor regulator/resistor is what's going bad? Also, when the fan is on 5 is makes a whistling sound, at 4 you can't hear it.

Are the brushes something you can buy over the counter and do yourself? A whole new blower motor assembly is $132, the regulator/resistor is $102.
 

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Golf R32 / Prev R170 SLK
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6,821 Posts

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17 Posts
Remove kick panel, 2 screw
Remove connector off fan motor
Remove cover under fan
Reconnect and put a volt meter on 2 spade terminals on motor to check for power there with ign on and fan on full
If ok then same as mine, brushes $35
If no volts check input to reg , brown to blue lead

Bazzle

Is there an easy way to test this?. I do have a meter that I picked up but have never used one before and not sure about the settings
 

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1998 , SLK 230
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222 Posts
Multimeter? If you are just setting for power set the meter to over 15V DC , typically 20V full scale DC. Hold the negative probe to a clean (not painted) metallic component of the body and check for power with the +ve (red) probe.
 
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