No need for that "programming clip" setup. You can simply solder a DIP switch in there and now it's easily configurable whenever you need to do it, for example if you change rear tire height or axle ratio. Also what you find on the chart may not get it the closest; I choose the setting that *should* work and the ones on either side of it, and try each against GPS until I pick the most accurate setting.
I did a write-up on the DIP switch mod for 1988-1991 clusters:
https://www.chevytalk.org/fusionbb/showtopic.php?tid/258562
And BTW what you're blowing out when applying 12V in the factory-recommended procedure are tiny fuses that are acting as jumper wires. If the fuse isn't blown it's the same as a switch being "on" or a jumper wire being in place. Fuse blown would be switch "off" or no jumper wire.
It's pretty simple. With my method you're just de-soldering those fuses and replacing them with a DIP switch. Check the chart and then set the DIP switch accordingly then go compare it against your GPS, might be right first time, if not then fine-tune a little bit trying the other settings. Cake.
Richard
