Removal and Service of VDO Instrument Cluster

Removal and service of the SI board

There are three screws holding the SI board in place. Use a small flathead screwdriver to remove these screws and then pull the SI board out of the housing.



With the SI board out of the housing, you can examine the condition of the circuits and the NiCad batteries. First, take a look at the contact points where the batteries are spot-welded into place. More than likely you'll see some corrosion where the batteries have leaked acid. If you are lukcy, this leakage is minimal and has not damaged the board. If the board is discolored or has stains where the battery acid has leaked, you may need to examine the condition of all the circuits.

Note that in the example above, there is some acid leakage in the bottom left corner, but this has not damaged any of the circuitry.

Use a razor blade or X-Acto knife to break the welds on the batteries and remove them. You can also use a solder sucker (solder remover) to heat up the bonds and dissolve them. Replace the batteries with Radio Shack NiCad rechargable batteries (part number 23-191 *** 1.2 volts / 700mAh ). That particular battery comes with solder tabs. I have also read suggestions to solder lead wires into the battery connections and run them to a remote battery housing which can be easily reached under the dash in case you need to change the batteries again in the future.

Clean any remaining acid corrosion off the board with a tootbrush and some electrical cleaner and then solder the new batteries into place. Then put the board back into the housing with the 3 flat head screws & reconnect the 2 ribbon connectors and ground wire.

If the board is too corroded to keep or if you don't feel comfortable soldering, new SI boards are available from a few sources, but they'll probably run you a couple of bills at the least. If anyone knows of other sources, please email me @ charlie at boxerworks dot com (trying to keep the spam robots at bay, you can figure it out) and I'll add them to the list.

Avoid the temptation to just ditch the board and put the cluster back together without it. The rest of the circuit feeds through the SI board, and without it you'll lose most if not all of your guages. So be sure to put it back in even if you don't replace the batteries.

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