Mercedes W124, A124 & S124 fuel gauges aren't all calibrated the same, but can be...

Ever wondered what that potentiometer was for behind the fuel gauge? Well this is what its for.

[@neilphilip2320]

There's a company called Spyda that sell a small PCB that allows you to recalibrate your gauge and set the quartile positions exactly - but this video is really helpful as are all of the ones I've looked at from yourself. Great stuff and thanks for all the time you obviously put into them.

[@glennstocker487]

How timely, I was just the other day in the instrument cluster of my daughters 190D and noticed the potentiometer, wondered what that was for- "No" I told myself don't touch it! and now I know, thank you, and yes that minor inaccuracy would bother me also. Cheers from the eastern states.

[@compu85]

I did a similar gauge calibration on my 99.5 Jetta… except in that case you completely empty the tank, add an exact amount of fuel in, and then adjust the instruments with a scan tool. My W126 has a dead spot on on the fuel level sender, I really need to pull it apart and clean it. It is nice the low fuel level light is done with a separate contact. I had bad solder joints on the cluster of my W126, that one was a bit easier to work on.

[@CEC-dv9zg]

Thx a lot, it’s helpful for my 500 CE M119 C124 Coupé with 75 Liter Tank

[@VINI8231]

Thx I looking for this everywere

[@bobracing85]

Nice video!

[@johnheartson6910]

Thank you so much for this video! My fuel gauge was wonky and I had replaced the sender which didn't help. I pulled the cluster and cleaned the trim pot, (also installed some LED's to stop the melting plastic). But then the fuel gauge read empty all the time. I bench tested using your procedure and found my fuel gauge is fine. I still don't know what's wrong, but I know its not the fuel gauge. Suggestions appreciated.

[@chillstar]

Have had an erratic fuel gauge for a few years now in my '94 S124. I had the cluster apart recently to repair damage done by the main illumination bulbs having previously been replaced with too high wattage. I noticed the calibration pot and, as you said in this video, thought its oxidation could be the cause of the gauge issue. I have some old audio gear, so have a can of Deoxit D5. Unfortunately, spraying the pot has not cured the issue. I am sure the problem is with the gauge rather than the sender or elsewhere as it usually jumps to empty or full, and will return to the true level if I bash the top of the dash near the gauge. I did wonder whether I should adjust the pot back and forth in the hope that could help with its cleaning. Was worried about doing so, but having watched this video, am less worried. I have a spare sender, so fairly easy to plug that in and use it to recalibrate the gauge. Do you think that's worth a try, or is my best bet to attempt to reflow the solder around the gauge?

[@r3FMusic]

Thanks..

[@paraskevasioannou7937]

saw a of yours about a w204 third brake light and I was wondering what the sense resistor is

[@lenliz2003]

Hi. I love watching all your videos. I do need some help. I have a w124 E200 1996. My temperature gage keeps going up and down by itself. Normally I just knock the cluster and the gage comes back down. Do do I fix that. The car doesn't overheat at all

[@aliezzeddine4321]

What tools is being used to simulate the resistance?

[@riadmelab9801]

I'm using a w124 cluster in a w123 sedan and the fuel gauge doesn't go down enough when the tank is empty because of the w123 fuel level sensor, is it possible to calibrate the gauge to read correctly?

[@IDYLBERRY]

I had a fluctuating fuel needle in my W124. I added 2 cans of Sea Foam fuel cleaner then drove 20 miles, but the issue continued. Ended up removing the fuel gauge sending unit and manually moved the float while my wife told what the gauge was doing. Put it back together and it hasn't fluctuated since. The problem I'm having is getting the sending unit plug gasket to stop leaking fuel. I didn't apply any sealant to the rubber as none was visible at disassembly. I'm concerned about over tightening the plug. Any suggestions are appreciated. Thanks!

[@MMWA-DAVE]

I have not pulled the sender apart yet on red so i’m not yet familiar with the process. Unless you are talking about the standard seal that is replaced with the entire sending unit - then you probably just need a new seal.

[@IDYLBERRY]

@@MMWA-DAVE Thanks for your reply. The gasket is about 4 inches in diameter with about 3/4 inch of gasket material making up the circumference. It looked in good shape without cracks or deterioration and was pliable.

[@chrisgooi]

Thanks for this brillliant video. How do you get this detailed, technical service manual please? Still possible to find one?

[@MMWA-DAVE]

So the wiring diagram featured in the video is out on the internet easy to get, W124 ETM, but the service manual, not so much. Its now very difficult to get unauthorised copies of service manuals even for old cars like this. MB actively goes after people sharing them.

[@chrisgooi]

@@MMWA-DAVE thanks. If only its for the classics (manual) , MB should be happy we are keeping it alive. A testament to their brilliant engineering of past. They should acknowledge the fact the there still millions of w126, w124, w140 running globally and remanufacture the no longer available parts.

[@omarpellot2065]

Can I use a fuel sender from coupe in a cabriolet?

[@MMWA-DAVE]

2 cars i am not familiar with - best asking the people in w124 enthusiasts group on facebook

[@vmlelectronics]

I've already calibrated the tachometer from my '76 Passat B1; on it's case, 60Hz relates to 1800 RPM. Are you an engineer or a technician?

[@ameershannaq3745]

How you doing I do watch your videos and I’m a subscriber on your channel, you do a great job , I want to rebuild my w124 1991 break calibers , I wonder where to get the repair kit, please advise me where to get it , thank you 🙏

[@MMWA-DAVE]

i bought my kits on ebay. Just make sure they are correct for the calipers, theres different brand calipers and different calipers per model. You should see which ones you have first before ordering.

[@ameershannaq3745]

I know I’m Looking at eBay they have too many kinds of repair kit for break calipers , can you send me a specific kit with link to eBay 👍

[@MMWA-DAVE]

@@ameershannaq3745 I already told you what you need to do, you are not going to get the right kit without finding what caliper brand you have installed per axle and what model car it is. You can have the dealership look up the part number of the repair kit with your vin, you will still need to know what brand they are.

[@ameershannaq3745]

Ok I got you now , thanks again 👍

[@Mahmoud.Jehad.Nassan]

i actually had this issue for ages i have T car and swapped it with sedan and i got left stranded on road multiple times because of this

[@MMWA-DAVE]

the level sender, if working, should still light the reserve warning lamp regardless of the accuracy of the needle as long as the bulb is working. That reserve warning lamp is a separate circuit.

[@Mahmoud.Jehad.Nassan]

@@MMWA-DAVE mine is the early one it doesn't have light for fuel

[@MMWA-DAVE]

@@Mahmoud.Jehad.Nassan interesting, was not aware of there being ones without the reserve warning lamp.