Just bought a 92 300ce with 140k miles. Everything works except the sunroof and the tach. Is this a common failure? Is there anything I can check before I pull out the cluster? I know it gets a signal from the ignition amp but where does the pulse go after the amp?

Ideally, you would have pulled codes from the Diagnostic Trouble Code socket in front of the battery Before you purchased the car. If you had not, now is the time to read them, before you do anything else other than fluids.

This will give you a good place to start. Of course check the fuses to make sure that there aren't any issues there as well. Inspect each fuse to make sure there are hairline breaks. Preferably, replace any aluminum strip versions with copper or brass fuses.

The sun roof can be retracted manually, see the manual (if you didn't get one, check on-line for pdf copies or eBay for a hardcopy). Every owner need to have and READ the owner's manual (I realize not a GUY-thing-to-do). Retracting it manually will confirm that there isn't anything mechanically wrong with it. Then pull the overhead light assembly, containing the sun roof switch and check its condition. To remove the assembly insert a plastic spatula on the left side and move the light console to the right. Then the left side comes down and out first.

Once you pull the cluster, assuming you know the proper technique to do so, (make sure you first go under the driver's side carpet and release the speedo cable from the clasp holding it to the floor). The actual proper technique is to go underneath the car and release the speedo cable from the transmission housing for maximum slack creation. The driver's side carpet techinque will give you more slack so that when you pull the cluster forward to get your hand behind, it doesn't put extra stress on the plastic connection to the speedo and damage the speedo.

You then loosen the connecting ring (it's only on there with hand-tight pressure). If it's stuck, use a dish washing rubber glove to give you extra grip). Now you can see the connection to the tach. While you're in there, might as well replace any burned out or suspect instrument bulbs

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03 CLK430 Cabrio 211K Pweter Silver/ Oyster Leather
90 300SEL 214k Pearl Black/ Alto Grey/Black Leather

Prior: 85 190E, 88 300TE, 89 300TE, 90 300E 2.6, 90 300TE, 92 300E 2.6, 91 and 93 300SL, 87 Ferrari Mondial Cabrio