Super B

Driving the car down the hwy and everything was fine. Pulled into a gas station for something to drink. When I came out and started the car all dash/warning lights work and LCD read outs work but all gauges are dead.

Turn the car off and the gas gauge needle vibrates slightly but enough that it makes a noise then stops and goes to it's home position.

I checked the fuses in the parking lot. Everything looked good. Car runs fine and all other electrics in the car are working.

Any body had this happen or heard of it?

DRBC43AMG

No idea, but you may search for a loose connector in the electrics.

cm60k

+1,

Also if you have K40 Relay, check all fuses in it, if they OK, then you may have a problem in (IC) resistor in the cluster itself...!

ZAYED,,

Super B

Hey zayed where abouts is that relay? I'll check it out.

I've have a hunch it's maybe a bad solder joint or something in the cluster since I tried it this morning and all the gauges worked.. I keyed it off and back on a few times then all the gauges went dead again.

I won't be able to look into it for a couple days as We're supposed to be launching our boat. But the more I've been digging online I'm finding this isn't an unusual problem on high mileage 202's.

Very little as far as solutions though.. I'll dig into it and see If it's anything obvious. Wish I had a pin out for the plug on the cluster as well as a way to check the signal down the canbus.

cm60k

Some W202 models comes with K40 Relay, that located in the CAN box..





ZAYED,,

RPB

Are you running aftermarket HID/Xenon lights? I started my C36 for the first time in a while the other day and when I turned on the lights the same thing happened to my cluster. I disconnected the battery for about 30 seconds and it was functioning properly again. My clock generally resets if they have not been used for a while.

GL!

Super B

Nope all stock in the lighting department. Still haven't been able to take a look at it. Got back from the lake and have more bugs to work out on the boat as well as the power adding controller (juice CS) for the truck died. So been busy trying to get these issues sorted before a big trip out in September.

It's a strange problem with the car as the gauges work fine about 3 out of 10 key on cycles. Please post if you find anything and I will as well. Hopefully it's nothing too hard to find.

cm60k

Did you diagnose the car..?, it may show something with Electrical issues, like SAM module or drop voltage..!!

ZAYED,,

Super B

Not yet zayed.. Just been buried with other non car issues.. As well as a little play time on the lake. But I may get some time today to take a look. I think I just figured out the problem with our truck so looks like some time just free'd up.

Excuse the ignorance as I'm still learning. But what's a SAM module?

As far as a obd2 reader All I have available is a craftsman 20899 reader/logger. Which is better than nothing but by no means shop worthy.

Looking at the live data on the reader, the engine control module and all the sensors are working. I just key cycled the ignition off and on 10 times or so and the gauges are working fine now..

The interior of the car was probably 100+ degrees F. So I'm running the car with the AC on to cool the cluster down and see if it acts up.

Super B

Yup sure enough.. The cluster is cold now and now gauges are dead. Cluster is coming out to take a look at the board.

Super B

Looks like I'm not the first to have this cluster out.

Super B

Hmmm nothing obvious.. I wonder if there is a VDO repair loop for these.

cm60k

SAM = Signal Acquisition Module, it's regulate central Electrical, it's under the fuse box..



ZAYED,,

Super B

Found it.. Just got to figure out what to do about it.

Super B

Well dug into it further and sourced a stepper motor online. The part number is 91 255 005 looks like they are £16

There is a small stepper motor with a gear box on top. As far as I can gather there appears to be no home sensor or wire. VDO must trigger it off the current of the motor in the reverse direction when the gear box runs out of range of motion or something along those lines. The gear box does not turn very smooth so I'm going to see if I can't open that up and see what's going on.

cm60k

Good to know; this been happen to a nice guy in Benz world, with his W210 E420,,

http://www.benzworld.org/forums/w210...nit-k40-5.html

ZAYED,,

Super B

Fixed! I decided not to take apart the little gear box since it has a spring in it and didn't want to deal with that. Added just a 1/4 drop I sewing machine oil to it and it's now smooth as silk. I instead turned the attention to the super small stepper motor gear and found that it was the root issue.

The gear over time had loosened up on the shaft. When I went to pull it off it slid right off with very little resistance. Since it has no sensor or any other means of detection, I'm convinced it finds the "home" position off an amperage signal from the motor when the gear box is at the end of it's range and the needle points the "zero" position.

What was happening is the stepper motor was driving the gear box to the end of it's range. But since the gear was loose on the shaft it was just dragging along. Hence the needle shake. The reason why it was worked when helping it along is because twisting it hard enough against the motor creates it's amperage signal and the driver considers that point home.

All that is needed to fix It I'm my case was a tip of a tooth pick amount of super glue to the inside of the stepper motor gear. Re assembled it with the needles back in their proper positions and she is good to go. Cheap fix..

cm60k

Smart move, you are a CHAMPION maaan, it will helps much...

ZAYED,,

Super B

Any time man. Thanks for the suggestions and hopefully this will help your friend out. I'm tempted to buy a couple of these stepper motors while they are available and add them to the spare parts for repairs down the road. I could see the tachometer gearbox wearing out over time. But who knows.

cm60k

I hope cluster repair companies not see what you done, if so, they will waiting you front of your door..,

let anyone in your home to open the door, EXCEPT you..

ZAYED,,