Print bed not heating P1S

My P1S now shows print bed at 0 degrees and it will not heat up and continue to print.
It worked fine before while printing TPU. I switched back to PLA and that’s when the problem arose- 0 degrees and refusing to print.
Oddly I think I had noticed the 0 degrees before this happened yet it was printing successfully with the TPU.
I’ve reviewed the WIKI instructions but the pictures don’t help much in locating thermistor and bed heating wires.
If you’ve experienced same problem, could you please provide any details which might be helpful. Like where exactly are the connectors and how to access them. And are there any gotchas to watch out for, like screwing up cables, losing spring parts when they’re taken off under the bed (if necessary), etc.
In the WIKI there is reference to having to heat up the connectors with a hair dryer to soften some sort of plastic goop that holds the connector on. This alone has me worried about proceeding correctly.
Any help and advice would be much appreciated.

Best, Bob