Try and top this. Merc. Spares costs !

[HERBIEMERCMAN]

the air con / heater fan packed up on my 97. e300 td. so investigated and found the zenner diode speed controller had burned out. it was larger than the diodes i have been familiar with but estimated it would cost circa £25. i contacted the mb dealers, they said it is a siemen's part and may not be available any more ? three days later they came back saying the diode was not available any more and would have cost £170. the full blower unit was available at £625. meanwhile i shorted out the speed control diode and mounted an on / off swich under the glove box, this gave fan on full speed or off. i contacted dronsfields at oldham explaining my predicament, they said the current speed control diode from the new models could be modified to do the job. they supplied the new update diode £170 and showed me how to machine the finned diecast finns in the blower motor to locate the new diode and how to alter the wiring. it woked perfectly, as far as mb main dealers were concerned i could either have the new blower motor at £625 or do without the facility, not nice. i contacted mb's HQ in holland to complain and they more or less told me to go away sexually. herbiemercman.

 

[television]

There are often these things on Ebay.

I can see the use for an after market conversion coming up.

Would you care to post me your old one

 

[jibcl500]

Thats a shame I could have given you what you wanted as I have one and as your a regular here it would have been free.



jib

 

[HERBIEMERCMAN]

sorry malcolm you could have had the original diode that failed but i slung it. herbiemercman.

 

[D1gger5]

Herbie

Did you try out suppliers like:-

Maplin
RS
Farnell

They supply all kinds of components not used in today's miniaturised, surface mounted circuit boards.

If you have the component number (e.g. 16uF capacitor, 1N4148 diode) and do a web search then other sources can be found.

 

[television]

Herbie

Did you try out suppliers like:-

Maplin
RS
Farnell

They supply all kinds of components not used in today's miniaturised, surface mounted circuit boards.

If you have the component number (e.g. 16uF capacitor, 1N4148 diode) and do a web search then other sources can be found.

These things are not that simple as they are potted and 50 components on the PCB

 

[D1gger5]

I know all about it but if it is not surface mount then that is much easier to replace. I built my own PC in 1992 and I now work with computerised control systems for a day job.

The reason for posting was to identify other possible avenues to save money replacing components.

 

[ALFIEBEARD]

Variable heater fan.

Hi just a thought , why not nip down to a scrapyard or go to Minor spares, (they are a company who deal in Morris 1000 bits) and buy a rheostat (if thats how its spelt) that was used on the old Fug stirrer heater units fitted to a number of 60s cars, just stick it in series with the positive feed to the fan,(after shorting out the original control unit. hey presto variable speed, the cost would be around £20 This is how I control the heater fan on my Cobra Replica.
Alfie B

 

[television]

Hi just a thought , why not nip down to a scrapyard or go to Minor spares, (they are a company who deal in Morris 1000 bits) and buy a rheostat (if thats how its spelt) that was used on the old Fug stirrer heater units fitted to a number of 60s cars, just stick it in series with the positive feed to the fan,(after shorting out the original control unit. hey presto variable speed, the cost would be around £20 This is how I control the heater fan on my Cobra Replica.
Alfie B

Those things waste energy, by getting hot, plus the output from all MB heater control units is only 0-5 volt at a few milliamps

 

[ALFIEBEARD]

Those things waste energy, by getting hot, plus the output from all MB heater control units is only 0-5 volt at a few milliamps

Hi Malcolm,
The energy wastage would,nt worry me as when running the alternator would be feeding it, also surely the fan motor is 12v, or are they data controlled ie the feed is either a high or a low ie 0v or 5v?..
Alfie B

 

[HERBIEMERCMAN]

as i explained in my posting i originally shorted out the diode and put an on /off switch on top of the glove box as a temp. fix. i could have put a rheostat there instead, again temporary untill i located the correct diode. the diode has to be compatible with the fan speed / temperature console, with the correct wattage. the diode has quite a large heat sink on the fan scroll with silicon contact grease to conduct the heat away into the finned cooling area. this is a fully potted bespoke diode which siemens produce, i tried several sources to replace but they all failed due to the specialised application and the essential compatability issues. thanks for your help and interest shown. herbiemercman.

 

[television]

Hi Malcolm,
The energy wastage would,nt worry me as when running the alternator would be feeding it, also surely the fan motor is 12v, or are they data controlled ie the feed is either a high or a low ie 0v or 5v?..
Alfie B

These things are not just a diode, they are a complete DC amp capable of supplying 12 amps