I just started a new 1 and thanx . Looking foward to talking to you.WP sensor feeds the PCM, which includes the fans.
Head sensor feeds the gauge only. The OP apparently rewired his car to use a single sensor on the WP. Odd modification considering having a sensor in the head is exactly where I would want to take my gauge readings. The heads overheat first if there is an issue. A total loss of coolant may not even be picked up from the WP sensor until it's too late.
As for your issue, perhaps it's better to start a new thread. Sounds like you may need a completely different set of troubleshooting steps, including telling us if the Check Engine light is on, and if you tried scanning for any codes. (hint: a CEL will run the fans constantly). I don't think we should hijack this thread. The OP hasn't even commented back yet after a week of us posting suggestions.