Ok first my wife has a 14 with 82K on the clock and yesterday coming home we noticed the A/C would get warm at red lights so I immediately knew there was an airflow problem. The car made it home before getting hot and I immediately shut it off to cool down.
After restarting the fan wasn’t coming on so I immediately swapped relays around and it came on. The issue is the original relays still operated their new functions (blower motor, rear window defrost). I checked the fan resistor (removed)and it doesn’t show any signs of heat damage to it or the plug. I’m going to assume the temp switch wouldn’t be this intermittent and that leaves me with disassembling the BEC correct? The fan is currently working on both high/low cycles and I’ve taken it through many drive cycles without a repeated failure.
If the BEC is burned on the high side of the fan should I wire an external relay? Replace the fan to ensure it’s not pulling too many amps? Does anyone have a diagram for this or any Advice? It’s my wife’s car and the last thing I need is blown headgaskets from her not noticing the temp gauge. I appreciate any help.

another thing I noticed today after driving it and finally getting a repeated failure the temp gauge doesn’t appear to be working correctly. The hushed was about 3/4 of the way up and I shut the car off and immediately restarted it and the gauge read 1/4 of the way up. It did eventually make it back to normal and once again after moving relays the fan came back on.

 

The temp gauge is damped to barely move in the normal range of operating temperature. Once the coolant gets above a certain threshold, it moves dramatically.

I had to replace the fan resistor on mine. It and the plug looked ok, but upon unplugging I could see the terminals had gotten hot and melted the interior of the plug a little. Ford sells a kit for replacing the plug, complete with shrink tubing to go over the spliced wires. I can't remember if the resistor was sold separately or not.

 

i replaced the fan assembly this morning and it has a new resistor. I have since suffered another fault and when the fan isn’t working the gauge acts differently than when it is working.

 

I hope someone more knowledgeable chimes in than me.