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R129 or W140 Cluster

6K views 9 replies 5 participants last post by  Bensbenz99 
#1 ·
Hey fellow members I hope someone can answer a question. I noticed today, when the sun light hit the cluster, that there is a small part number just above the trip odometer. The number is 140 542 27 06. Does this mean someone changed the cluster with a W140? This would explain why the speedo is erratic and the fuel gauge reads 1/4 tank when the tank is empty.
 

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#2 ·
The odometer design on these two models were identical so its possible it was never swapped. I have the digital style one and took a peek at mine but it does not have a visible part number like yours does. Maybe someone with an early model can check if theirs also starts with a 140.
 
#3 ·
The prefix of a part has no bearing on what chassis or model it's used on. There are many parts used across model lines that have a prefix for another model.

Since I have a couple of W140s and an R129 of the same general vintage, I can definitely compare them, and the cluster in the later W140 is identical to the one in my R129.

Understand that the legend "strip" along the bottom where your indicator lights are located is about the only real difference. That and lamps being installed in those positions (or not.)

Dan
 
#4 ·
The 140 number is the speedo gauge/odometer gauge, and it does not refer to the rest of the cluster. The analog R129 cluster gauges(analog odometers) the gauges are compatible with W140 analog cluster gauges are compatible. The R129/ W140 clusters with digital odometers have a different gauges(they are pinned different).

Now, the whole cluster electronics is different, yet they are electrically compatible to about 98% to 99%. I want to say the illumination pin on the R129 is in different location than W140, but plugging a W140 cluster in R129 you will not blow up anything, but(A big BUT......) The fuel gauge will be different, yet the big problem is the W140 cluster cannot process the speed signal from the wheel sensors/Transmission sensor, and the early R129's from the 90 - 93 is the SH*TS when it comes to the clusters very inconsistent. The biggest problem is the R129 clusters process this speed signal. The speed signal is sent to the climate control, and most importantly sent to the top controller, and the top controller uses this speed signal to give you permission to raise the top, lower the top.

Martin
 
#5 ·
Martin,

A related question, if I may?

I have always pondered whether or not you could swap one of the later electronic clusters out for one of the earlier ones with the analog odometer?

I wonder if the signals are there and if the mileage is recorded into ECU memory somehow on the earlier cars with analog odometers...

Dan
 
#6 ·
First question, after 96 it was a different cluster, and the "three" LCD clusters only have two rectangular connections which came in +96/97. All the other clusters are have two big circular connection with two rectangular connections, so for starters one needs the same connection. When say later? how later?

Second Question, funny you say this about the memory chip on a analog cluster. The chip is on board, but not sure what its purpose.

Upto 94(maybe the 95's too) the R129s came with a mix of different clusters. I have a 92 SL320 cluster it is digital. I have 94 SL600 it is analog. My 93 SL500 is analog. My 95 SL320 is digital..

Martin
 
#7 ·
Update it was W140

I've read a few post from fellow members that said the W140 cluster partially works in the 500sl. Well today I pulled the cluster to install the replacement cluster I got from a fellow member. I'm no expert but I think the old cluster was from a w140.
The good news is that the new cluster reads MPH instead of KPH. The speedometer now works vs the old unit. My fuel gauge now reads the correct amount. The old cluster read 1/4 more than was in the tank (this caused me to run out of fuel on a Friday during rush hour). I changed the back lights to LED. This gives it a whiter light.
The bad news. The odometer had a bad gear. I pulled the cluster back out and swapped the odometer motor and gear from one cluster to the other. Odometer now works flawlessly. Took it for a long drive and did get the dreaded dash flash when using the turn signal. It only happened once so maybe I'll have some time before I have to fix it. If any members can link me to the procedure to replace the capacitors (with pictures) I would be most grateful.


Old cluster
 

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#8 ·
The replacement cluster worked for a day, then the old capacitors gave up. I've put the old W140 cluster back in temporarily. I purchased the capacitors for under $3. My next project will be swapping the new ones in. At least I got a day with the working fuel gauge and speedometer. Before someone comments I've already had the capacitors changed in the W140 cluster. I've also changed the fuses and OVP relay.
 

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#10 ·
Success! Soldering in the new capacitors was easier than expected. Just make sure to put the stripe in the same place as the old one. The cluster is working like new. I would have never tried this without the knowledge I learned from fellow members. Thanks to all who have shared.






Old capacitors
 

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