1992 2.3L - engine fan not coming on, temp gauge not rising, A/C not engaging.

Hi, new to StangNet, We have a 1992 2.3L non turbo convertible that is giving us some problems.

1. - Engine cooling fan not coming on. I've read that it is common for them to not come on until the temp gets very hot, but my temperature gauge doesn't seem to be working either.
2. - Temp gauge not rising. Stays at the bottom of the guage, even when the engine is hot.
3. - A/C not engaging.

Now, I've gone through and checked wires and harnesses and I've cleaned a re-grounded all of the grounding points. I've unplugged the engine fan and tested directly to the battery - and the fan works great when supplied with direct power. I thought I had traced the issue back to the "N" relay control module, but I just put in a new one and nothing has changed.

According to Haynes - if the fan motor tested ok, which it did, the fault lies in the coolant temperature switch, the fan controller, the EEC system, or the wiring.

Is the coolant temperature switch the same thing as the coolant fan temperature switch?

Could the A/C be related to the diode?

Any help would be greatly appreciated!