Trying to help my mom with an issue in her car. She has a 2005 Ford Five Hundred and a while ago it started exhibiting the issues described on this page:

https://www.fordtaurus.net/forums/viewtopic.php?t=15742

So I pulled the dash and checked those solder joints. They didn't look bad but I re-soldered them as described. Unfortunately that had no effect on the issue. So she sent the dash to these guys:

https://autotechrescue.com/

and they apparently "rebuilt" the dash or whatever they do. Got it back and it had the same issues.

I have checked all fuses and the ground connections and the alternator as I've seen those as indicators of this problem in other places and see nothing wrong in those areas.

I contacted them and they said "Have you checked voltage right at the harness going to the instrument cluster?" but I am having a hard time finding a pin-out for that plug that connects to the dash to be able to check those voltages.

Have any of you seen this issue and had success fixing it or can you point me to where I can find that pin-out so I can check those voltages? The VIN number for the car is 1FAFP24147G109170 if that helps.

Thanks in advance.