Save yourself a lot of time, unplug the sender and take a jumper wire from the #3 pin socket to the #2 pin socket turn on the ignition and you should see the warning light on the fuel gauge come on. Next take the wire and place it in the #3 socket and the # 1 pin socket and the fuel gauge will read full. Now you know it's not the grounding on the instrument cluster but rather a problem with the sending unit. My sending unit 1987 560sl also looked very clean, turned out the ground pin had no conductivity. Tried heating it, cleaning it to no avail so hence a new unit.
I had the same issue, but it was my temperature gauge, it turned out to be the contacts on the back of the instrument cluster, cleaned and lightly sanded the contacts, and that fixed it for good,, hope this helps,, great videos,,keep them coming,,,
@@mericavids did I miss that? I can give it a try. I just noticed that the fuel needle only does it at certain areas. Also noted that my temperature needle is starting to do. I think it may be something else. 🤷♂️
Likely instrument cluster grounding is the issue. I’m seeing other comments in this video comments referencing other gauges inciting the fuel sensed such as temperature becoming unstable. This is a common issue with a simple solution. These instrument clusters need a second ground added as they age. Why this is needed has been discussed elsewhere, has to do with the original ground weakening over time. There are videos showing it done, you add a ground wire to a nut on the back and to the steel frame of the car providing a ground. About 16 years ago I had to figure this out when there was less info about it, it was a real pain and I waisted a good deal of time before discovering this. I have this same 380sl model and year. When removing the cluster and reinstalling assure you disconnect the battery otherwise you can easily cause a short circuit and blow a fuse or worse.
Thanks Eric. After I made the video, I noticed that it was only happening when the fuel level got to a certain level. I also noticed that the temperature gauge jumps every once in a while. Is it difficult getting behind there? I haven’t looked into it yet.
@@sophiathe380sl it’s super easy to remove the instrument cluster especially compared to the complexity of the other work you have done. You need a hook like tool (comes in a pair), I own both the original Mercedes tool and one I bought on amazon (had forgotten I had original) and both original and amazon are equal no matter what the reviews say so you can get the instrument cluster removal tool cheaper and faster from amazon. I will look now at amazon seller I used and reply to this comment. All you need is wire and possibly a nut and screw for the grounding post behind the cluster. When you remove the cluster, you will see nuts holding the back on to the instrument cluster. Simply loosen one on the left (what I used) and wind wire around the post and tighten. Then secure the other end of the wire to the very visible grounding post you will see looking back into the opening where the instrument cluster opening is. You may be able to reuse a nut on inside car grounding post similarly (loosen and put under nut) or a second nut and screw you add. The grounding post has a place for two nuts, the top nut has an obvious grounding wire going to it. Again very important, disconnect the battery first and then wait to reconnect until reinstalled. omes in a pair), I own both the original Mercedes tool and one I bought on amazon (had forgotten I had original) and both original and amazon are equal no matter what the reviews say so you can get the instrument cluster removal tool cheaper and faster from amazon. All you need is wire and possibly a nut and screw for the grounding post behind the cluster. When you remove the cluster, you will nuts holding the back on to the instrument cluster. Simply loosen one on the left (what I used) and wind wire around the post and tighten. Then secure the other end of the wire to the very visible grounding post you will see looking back into the opening where the instrument cluster opening is. You may be able to reuse a nut there similarly (loosen and put under nut) or a second nut and screw you add. The grounding post has a place for two nuts, the top nut has an obvious grounding wire going to it. Again very important, disconnect the battery first and then wait to reconnect until reinstalled.
Here is the amazon cluster tool, works as well as original Mercedes tool. “Mekar Instrument Cluster Removal Pulling Hooks Tool Dashboard Removing Tool for Mercedes Benz”
Bouncing needle is a grounding issue. Remove cluster and add ground wire fro right speedo top screw to body. I just drilled a hole in metal part behind cluster and connected the ground wire wuth a screw.
Btw, you got vacuum leaks. This may be a secondary cause if your hot start issue. Economy gauge should be at 0 @ idle rpm unless AC compressor is running. As to fuel needle, take out cluster and check the GND connection for all three cluster. They are connected by screws to a ground bus. Also I check electrolytic capacitors in each cluster and the connection of gauges to circuit board
Ya, that’s what I’ve also read. It happens on the temperature gauge as well. It’s weird because it only happens when the gauge is in a particular area. Same case for both gauges.
