Since there's been more interest in this project than I expected, I'm going to try to answer all of your questions...
FYI, this fan measures only 12 inches in diameter, but seems to be doing the job. Don't know if it was one of two on the 95 Corolla's since it had already been removed and tested when I got it at the junkyard. Cost was about $30 - I bought it last year and don't remember exactly.
70Duster440, I might try the wiper motor wire if I notice any problems or worry too much about what I'm tapped into now. I don't have an oscilloscope, so I can't see how 'clean' my voltage is. I've been reluctant to mess with that bulkhead connector since it's a common source of electrical problems. I also don't like splicing into existing wires. I tapped into the voltage regulator at a spade connector where the male connection had a hole in it. I ran the controller wire through the hole and slid the wiring harness connector over it.
This was just temporary to figure out if it would work. If the wiper motor is a better place to tap into, I'll do that. For now at least, the voltage regulator tap is working OK. This project won't be 'done' until all connections are soldered and have shrink wrap for a watertight connection.
My controller is also near the battery, just zip-tied to the radiator core support for now.
rrvolare, I didn't get a schematic for the fan, but there is only one connection with two terminals: 12v and ground. If you hook them up 'backwards', the fan turns backwards from how Toyota oriented it (from a puller to a pusher). Because of space limitations, I installed it on the front of the radiator, so it's a 'pusher' now. I've read that these electric fans aren't as efficient if you reverse the polarity, but it seems to be enough for my situation. It's a 225 with Clifford headers and dual exhaust that's been converted to a Super Six with a Carter BBD.
If you were asking about a schematic for the controller, it had a diagram showing the wire colors and where they go, but the controller itself is a 'black box' in the diagram. Hayden probably thought (correctly) that people would just make their own version of it if they showed the details of how it works. I may add an inline fuse later as you suggested; this project is still in the early stages, but so far it looks like it's going to work.
cudajim, you're probably right about the fuse not being necessary since it's not actually supplying power to the fan. The fan power is protected by an inline 25 amp fuse between the controller and the fan. But it sure wouldn't hurt to have some extra protection going to the controller's power source, especially since the Dart's wiring system is so old. Also, I don't know how much current the controller uses since the instructions don't say. It probably isn't very much, but more protection couldn't hurt...
I did notice a couple of things about this fan controller that I like.
First, it's set up for two fans in case you have a system that requires a lot of cooling power. (My factory-original setup with a 4-blade fan and no shroud indicated one fan would be enough).
Second, there is a separate wire from the controller that connects to the A/C system if you have one. I suspect that it's an override that turns on the fan(s) when the A/C is on. I'm
not a mechanic, so I'm not sure. I think that wire could be set up to a manually-switched 12v source so you could turn on the fan whenever you want. That would be an interesting option, so I'm just going to tie that wire off so it will be available to use in the future.
I included two pictures of the hookup. As you can see, it's only temporary for now. The temperature sensor is just wedged into the upper frame of the radiator with some zip-ties. The controller instructions say you're supposed to insert in in between the radiator cooling fins after you've opened up a space big enough for it to fit. When I did that, I got a slight leakage of coolant. After sealing it up with JB Weld, I put the sensor where it is now. So far, so good.
Second pic just shows where I tapped into the voltage regulator. The mounting (ground) screws were a little loose, so there's another wire to ground the reguator to the chassis.
Most of my little projects come from ideas I get from internet forums like FABO. It's good to be able to 'give back' for a change, so if anyone has any questions about this, just ask and I'll respond.
It may be a while before I declare this project completed since the really hot weather is still a couple of months in the future, but I plan to let you know how it all works out and maybe post some pictures of the final setup.
