PeachParts Mercedes-Benz Forum - View Single Post

Jeremy5848 · #6 05-09-2007, 02:35 PM

I just had my '87 cluster all apart to fix a bunch of problems. AFAIK, the only LEDs in the '87 are in some of the switches (power windows, etc.).

All of the various indicators in the cluster are small incandescent lamps. The dealer will have them, the aftermarket people might have them. Be careful, some lamps look OK but are just a couple of mils too large to fit in the sockets.

Disconnecting the battery and marking the various wires to the cluster is a must, else problems like your arise. As has previously been said, the only power to the cluster with key out is (a) 12 Volts to the clock and (b) IF the lights are on, power to the cluster illumination rheostat and lamps.

The "tach power line" that touched and made sparks is the clock power wire. It has 12 Volts on it all the time. It should not have made the glow plug lamp burn out, as a previous poster noted. Much of the internal wiring in the cluster uses printed traces that might have fried when the short occurred. You probably should disassemble the cluster and check for damage.

When you take the cluster out, you will see that one of the indicator lights in the lower row is attached to the back of the cluster by a wire pigtail so it stays with the cluster. All of the other lights are in sockets in the cluster or are on wires that stay with the car. When you go shopping for lamps, take the cluster along and make sure the new lamps physically fit into the one socket. The other lamps in that row are the same kind -- 12 Volts, 1.2 Watts.

BTW, the lamps in plastic sockets that twist and come out of the cluster are all one piece, lamp and socket. The lamp is soldered and glued into the socket piece. The entire thing is replaceable.

The clock has two electrolytic capacitors that fail with age. My clock didn't work at all until I replaced them, now it runs just fine. Replacing the caps is something you can do if you have the tools and ability to solder on tiny PC boards. If not, have someone do it for you or buy a replacement clock.

Jeremy