Originally Posted by thomas91gt
So what about using a fan off a 94 gt?
You could do that too.
However, using a 2 speed fan such as those on the 94-95 Mustangs leaves you with a choice of just using the high speed circuit of the fan motor or trying to figure out how to use both circuits.
I did quite a bit of research some time ago toward using the SN95 fan on my 86 GT.
Finding a thermostat and relay system for a 2 speed fan other than what was used on the SN95's was impossible then. Maybe now there is something available, I don't know.
I initially looked at using the SN95 controls, but it quickly became apparent that the older 89-93 ECU's did not easily lend themselves to interfacing with that type of control, some would not work and the SN95 system was not that great anyways, being subject to a recall for possible burned up wiring and fire.
At that point I sat down and tried to figure out how to wire up the system myself.
What I ended up with is a bit complicated, but it looks like it will work to me.
I tried to get verification of my wiring design from several engineers and automotive wiring sites, but the best I could get out of them was, "It looks like it will work".
That wasn't very helpful to me at the time though, because I think it will work too and I was looking for verification, which none of them would confirm. Needless to say my faith in their abilities was somewhat shaken.
Here is a copy of what I came up with. I make no guarantees and use at your own risk.
I believe there are enough safeties built in to protect a 12 volt system, but you never can be 100% sure until it has been thoroughly tested.