For my 2005 SRT6, Pin 3A is Ground and 13A is power to the Instrument Cluster Lighting. The actual connector pin-out listing is on page 8W - 80 - 37 (page 1855 of the pdf) of the SRT Service Manual. This may or may not be the same for your year/model. Verify pin-outs in your applicable services manual. I plugged mine back in for EVERY test. The pins are small and you risk damage to your cluster by tapping the pins directly.

You can find the service manuals here...

Crossfire Documentation Collection