1996 xj cts harness

[1996XJ]

Hello everyone I have a couple of questions and need some serious help with regards to my coolant temp sensor located in t-stat housing. So I have a check engine light, rough idle, running rich, key trick neted coolant temp sensor or connector. I put in a new temp switch, but my e-fan is not turning on and still running rich. If i disconect the harness fan turns on. I found a diagram online for the plug connector and bought a new plug part 254 for the connector. Now I know the tan-black wire goes to the pcm so could I just trace this to the pcm tap into it and run a wire directly to my cts harness? As for the blk-light blue wire can I ground this out to the block? Or where does that wire go to? Thanks!