R129 Blower Resistor replacement

[SKELLIG]

Hello, new to the forum and hoping someone may have replaced their R129 Heater blower resistor.

I have been trying to source a replacment blower motor resistor for my 1991 R129 SL300 as the blower is not responding when speed control is switched on. My mechanic has tested the blower which works and so isolated the problem with the resistor. I have bought two (said they were compatible) but they do not work and the lead is too short plus it has a green and red wire instead on the blue and red. Is there a right hand drive version ? any suggestion on sourcing the resistor or perhaps a RHD verions / part number ?
I can buy a complete heat sink and resistor second hand or blower, heat sink and resistor but more costly again - any suggestions on sourcing would be appreciated.

 

[R129mine]

I had the same issue, this is the item i purchased on eBay last year (£66)

there are indeed 2 lengths of cable, LHD and RHD, but you could just lengthen the cable if you are handy with a soldering iron, and use the correct gauge wiring (I am not that handy so looked for a while to find the correct one

attach is a picture with the part number on it

found one for nearly double the price

🏷 min. Price: 18 € Used Fan resistor / Resistance

🏷 min. Price: 18 € ➡️ SEARCHING Fan resistor / Resistance FOR YOUR CAR AT A GOOD PRICE from ⚡18 ? SROTAS24.CO.UK ⏩ PROVIDES NEW AND USED AUTO PARTS FROM SUCH FAMOUS CAR MAKERS AS AUDI, BMW, VW, VOLVO, MERCEDES-BENZ, OPEL, FORD, RENAULT, NISSAN.

srotas24.co.uk

 

[mioba]

Have you tried a MB dealer based on VIN, it will be the right one then.

 

[SKELLIG]

I had the same issue, this is the item i purchased on eBay last year (£66)

there are indeed 2 lengths of cable, LHD and RHD, but you could just lengthen the cable if you are handy with a soldering iron, and use the correct gauge wiring (I am not that handy so looked for a while to find the correct one

attach is a picture with the part number on itView attachment 121892

found one for nearly double the price

🏷 min. Price: 18 € Used Fan resistor / Resistance

🏷 min. Price: 18 € ➡️ SEARCHING Fan resistor / Resistance FOR YOUR CAR AT A GOOD PRICE from ⚡18 ? SROTAS24.CO.UK ⏩ PROVIDES NEW AND USED AUTO PARTS FROM SUCH FAMOUS CAR MAKERS AS AUDI, BMW, VW, VOLVO, MERCEDES-BENZ, OPEL, FORD, RENAULT, NISSAN.

srotas24.co.uk

R129mine,

Thanks for taking the time to reply and posting a very helpful response. I have ordered 2 different resistors (without the heat sink) which were listed as correct for the car but both were the LHD version with a short cable and different colour wiriing (green instead of blue if relevant).
I was thinking about extending the wire but they also did not work when plugged in as a test i.e. the heat sink got hot but the blower would not operate. I did not have a part number on my old one so prompted me to reach out to fellow R129 owners on the forum.
Given the car is laid up for a few weeks and taking up my mechanic's garage space and not wanting to take any further chances I ordered a second hand part from 129co ... otheriwise I would have tried the link you provided which look correct and is cheaper - I notice the part number is 140 - is this an interchangeable part with the W140.

I will post if it works and the part number when it arrives so at least fellow R129ers can benefit from your suggestion and hopefully the conclusion of my replacment. Thanks again for your help.

 

[SKELLIG]

Have you tried a MB dealer based on VIN, it will be the right one then.

Thanks for your reply, as I posted to another reply, I have ordered a second hand part from 129co after two unsucessfull orders for just the resistor, I will post if thsi part works.

 

[R129mine]

hope it works, I remember taking voltage readings when testing the resistor,

• speed 1: 3.2V
• speed 2: 5.49V
• speed 3: 5.92V and same for speed 4

Did the same test again with the new one and when using setting 4 the voltage went up, result! I think it was just over 11V

I would grease the wiper arm mechanism while you have it off with lithium grease and I also took the cabin filter box apart and cleaned it up as I had a ton of leaves hiding in the metal grill. Oh and this summer I took the wiper arm off again and sanded it down and resprayed it as the colour had faded quite a bit (should have done it when I did the blower motor resistor replacement)

I also cleaned up the blower motor plastic as both rotors were black, and now they are back to the original colour, somehow it I feel better about having air blown in my face when it comes from a clean blower motor Cabin filters only do so much