w210 digital climate fan speed

astradave81

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Hi there, my e320 1997 w210 model climate control is playing up. the fan works correctly on the 1st 3 speeds then the 3 after that it stays as if it were still at no.3. The climate control has always had no leds that work on it ie when you press heated screen the fan switches to max and blows at the screen but the red led in the switch doesn't light up. Same for when you press auto, charcoal filter and so on. The Rest button has also never worked which gives me the problem of not being able to perform the self diagnostic. I'm thinking it could be the rectifyer?? When auto is pressed it feels like it still only blowing at speed 3. Is the rectifyer the same on the models without digital climate and where abouts is it situated. Would anyone have a wiring diagram showing how to test the rectifyer?? Any help much appreciated.
 

television

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I thought that these cars only had a 3 speed for the fan setting,,there is no rectifier,,but you have a regulator but that would appear to be OK. The REST enables warm air to come in while parked up for a while
 
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astradave81

astradave81

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It has 6 stages on the digital display. The speed increases at the first 3 but then blows no harder after that. It used to but has just stopped this week. Hope this helps
 

television

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OK I will take a look at the system over the weekend and see what info I have
 

bigasotonuk

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Hi,
With those faults on the control unit I think I would be trying to source a second hand one first before I did anything else, not sure regarding the specific fan speed issue but one thing I do know is the fan in the climate control is apparently different to the standard heating system, and is more expensive, so possibly has the speed regulater built into the fan assembly.
 
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astradave81

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It has always had these faults with the display, with regards to the switches lighting up when you press them but it has never stopped the fan from working on the upper scale before. So thought it must be something else at fault. All the buttons work except the rest one. Typical when that is the diagnostics button eh:(
 

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i would just check the voltage at the signal wire at the regulator - if it ramps down (or up, can't remember) with each speed setting the reg will be at fault.
 
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astradave81

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Does anyone know if the regulator is seperate to the motor or is it all part and parcel of the same thing, and where is it located.. Thanks for any help..;)
 
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astradave81

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Thanks for that link. Yep it would appear item 221 is the item at fault. We call them a resistor block where we work. The voltage varies into 221 but coming out it only varies for the 1st 3 stages of fan control not the last 4. So i guess i'll be pricing one of these up tomorrow. Would you happen to know if the they are the same on both sorts of fan control. ie digital climate and manual fan control. Just incase i try to source a 2nd hand one? Thanks.
 

Markieboye

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It's about 200 notes for a new one.
 

television

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Thanks for that link. Yep it would appear item 221 is the item at fault. We call them a resistor block where we work. The voltage varies into 221 but coming out it only varies for the 1st 3 stages of fan control not the last 4. So i guess i'll be pricing one of these up tomorrow. Would you happen to know if the they are the same on both sorts of fan control. ie digital climate and manual fan control. Just incase i try to source a 2nd hand one? Thanks.

I have never seen any other than a 3 stage,,any more are done on the control box,,I doubt that it is at fault, as when they fail you only get 1 speed working,,the slowest
 

television

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These are not resistor packs and are a semiconductor
 
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astradave81

astradave81

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When you say you have only ever seen a 3 stage, do you mean 3 speed? Mine has 7 speeds Each speed indicated by the lcd display lighting up an lcd block. The feed into the block increases each time the fan speed is increased on the dash but the power to the motor only increses for the first 3 then no further increases after this giving a maximum power to the motor of around 11.27 volts. If you doubt it is this part at fault what could it be?
 

television

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I will have a look at the 210 control unit and see what I can find
 

television

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You can check the output from the control unit in the car that drives the fan regulator.

1 = 0.8v auto and 0.8 volt man
2 0.8 to1.1v 1.0v
3 1.1 to 1.8 1.5
4 1.8 to 2.8 1.5
5 2.8 to 3.5 3.2
6 3.5 to 4.5 4.0
7 4.5 6.0

If these are correct then maybe the reg has failed,, you can test on an ohm meter
 
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astradave81

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It was the regulator that had failed. Got a new one for a c class as it looked the same but had a slightly different wiring connector and the metal on the back of it was slightly larger. Trimmed it down, swapped the terminals round and hey presto a brand new reg working for £65. Bargin, mmmm feel the power:)
 

television

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Pleased that its all fine :D:D
 


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