No reading from the instrument panel
05-23-2005, 05:16 PM
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1987 Mercedes 190E 2.6
No reading from the instrument panel
Ok, here I am driving down the road, cruising in the 1987 190E 2.6 and all of a sudden, BAM, my oil level gauge, gas gauge and water temp gauge all goes to zero. On the same gauge, the economy needle is still working (must be associated with the RPM gauge to the right). I checked the fuse box to see if something blew but I don't see anything. By the way, why do they make it difficult to get to? Anyway, I plan to pulling the fuses one by one to clean it and check it. What could have caused this? What other item should I check? I did notice in the fuse box that there are two silver boxes (looks like relays) as well. Could this be the cause? 
Please help.
Please help.
05-23-2005, 08:36 PM
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'85 190E 2.3-16 '99 C280 '11 GLK350
Before you start pulling fuses (it's fuse #9 for the cluster), it seems that the problem is isolated to the left cluster. If the tach and clock are still working and the cluster illumination is working, then it's probably not a fuse. The "Economy" gauge is working since it's operated by a vaccum line, not electrical. The speedo is cable driven, so it's unaffected by power.
It could be that the left cluster has lost the "ground" contact with the center cluster. The right side gets it's ground from touching the speedo cluster and over time the solder spot or contact vibrates a break or crack.
It could be that the left cluster has lost the "ground" contact with the center cluster. The right side gets it's ground from touching the speedo cluster and over time the solder spot or contact vibrates a break or crack.
05-24-2005, 07:34 AM
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1987 Mercedes 190E 2.6
Yeah, everything else works, to include the clock, tach and lights. How do I check this ground? Do I need to pull the dash out or is there someway I can just pull the instrument cluster out? Thanks for your help. Mahalo.
05-24-2005, 05:06 PM
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'85 190E 2.3-16 '99 C280 '11 GLK350
To check and/or repair the ground, you'll need to pull the cluster, not the dash, out. While there is some slack built into the cable, the only way to do that without risking stretching the speedo cable and ending up with a bouncy low speed needle, is to undo the cable first, either at the trans or at the back of the cluster before moving it.
Remove the underdash panel and knee bolster; then remove the black plastic air ducting that connects the left side vent with the center console. The pieces are pressure fitted and pull right off. With the ducting removed, you should be able to trace the speedo cable to the knurled brass connector on the back of the cluster and undo it. Then just push the cluster from behind and it will slide out towards the steering wheel. It's held in the dash by a rubber friction gasket and once it clears the dash, you can disconnect the wire plugs, which are unique and polarity coded so you can't reconnect them incorrectly. You'll need to unplug the outside temp display cable and the vaccum line that feeds the Economy gauge. Angle the cluster up to clear the steering wheel and this is what you should end up with (ignore the clipped wire in the picture).
The brown area is where the speedo and left cluster are held in place with sheetmetal screws. Undo the screws and remove the instruments, check for the ground contact. If you want to be certain, you can always solder a short ground jumper to the metal body of the right side cluster.
It would be a good time to replace the illumination bulbs for the cluster and warning lights at this time.
Remove the underdash panel and knee bolster; then remove the black plastic air ducting that connects the left side vent with the center console. The pieces are pressure fitted and pull right off. With the ducting removed, you should be able to trace the speedo cable to the knurled brass connector on the back of the cluster and undo it. Then just push the cluster from behind and it will slide out towards the steering wheel. It's held in the dash by a rubber friction gasket and once it clears the dash, you can disconnect the wire plugs, which are unique and polarity coded so you can't reconnect them incorrectly. You'll need to unplug the outside temp display cable and the vaccum line that feeds the Economy gauge. Angle the cluster up to clear the steering wheel and this is what you should end up with (ignore the clipped wire in the picture).
The brown area is where the speedo and left cluster are held in place with sheetmetal screws. Undo the screws and remove the instruments, check for the ground contact. If you want to be certain, you can always solder a short ground jumper to the metal body of the right side cluster.
It would be a good time to replace the illumination bulbs for the cluster and warning lights at this time.
05-31-2005, 02:21 PM
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1987 Mercedes 190E 2.6
MTI, Thanks for the information. It was not as easy to pull those stinkin ducts but it worked out fine. These cars are made like women pants...everything tight.... 
