Well, I've been trying to figure out my overheating issue for some time. I checked the connection on the resistor and wiring and everything looks surprisingly great.
Looks don't matter, and there is a fuse associated with this circuit. Check your owner's manual, and check the fuse. You might want to swap some relays around if you have one that is the same relay type for another device that you can check works- like the headlights for example. I think the SVT wiring uses the small relay for the fans, but I can't remember.
My A/C does not work, however, I tried turning it on and set the fan speed to high and I kept hearing this "click" at the engine. It would happen every 5-10 seconds and my fans were not turning on. Not sure if this makes a difference, but the engine would ever so slightly rev up at the click, and then rev back down. Is this the relay? If so, any way to check them without just replacing?
The clicking is the AC compressor clutch. The AC probably isn't working very well because there's no air moving through the condenser because the fans aren't working. Then there's the heat from the radiator, but I'd wait on diagnosing that until you get the fans working. The fan should come on with the AC working like it is, and your idle is going up like it should when the AC is on, so that's probably all good. With it clicking so much, it might be low on refrigerant- indicating a leak, but it's not all leaked out yet. That would cause this problem. To bypass the AC itself but see if the fans work do this: unplug the AC clutch, and move the connector out of the way of the belt. Now, locate the low pressure switch which should be in the passenger fender under the headlight. Unplug that switch, and use a piece of solid copper wire or a paperclip to bridge both points on the switch. Tape it up if needed to be sure that it is still making a connection, but not able to short out. Now see if it works. Start the engine, turn the AC on, and within a few seconds you should have a running fan even if the resistor is bad. If you don't, then use a DMM to test for power at the resistor or fan pigtails. If you find power at all these points, then you can assume that you won't find resistance between the fan pins because the fans are fried. If you don't find voltage there, then you have a fuse or relay problem. IMO, I'd check the fuses and relays first before going through all this diagnostic trouble.
Also noted, this could be an entirely different issue, but I am very slowly losing coolant. Its over a few months so I'm not sure if I have a very slow leak or its just part of an older car. (115,000 miles)
Coolant leaks should be repaired ASAP. It will eventually develop into a larger leak, and that might cause a bad head gasket if your current overheating hasn't done that already.
You have multiple problems IMO. Your first problem is getting the fans to work, then you need to repair the coolant leak which might be as simple as replacing the overflow cap. Those do go bad and leak coolant over time. It's a separate issue from the fan though. Most Zetec engines, incl the SVT, leak around the thermostat housing, and typically the housing itself cracks. Look for dried up coolant in this area.
