Got an '87 Sport Coupe with the 2.8L, and after a bit of work replacing the spark system, its been running pretty smooth for a while now. The fan has always come on as soon as the key is turned, which never bothered me. However a few months back it failed to turn on, and I ended up getting the car reaaaaal hot before i realized it was not being cooled down (lame *** dummy gauges are a pain lol). I've had the fan wired to a switch in the cabin for some time now, but the switch always ends up getting way too hot and melting. So i hooked it back up to where it was hooked up before, threw some wire nuts on there, and the fan did turn on the first time i turned the key. however, about 9/10 times it just refuses to turn on with the key at all Anyone have any idea why it's doing this, and what i can do to get it back to running with the ignition reliably? I know getting it hooked back up to the temp sensor would be optimal, but I imagine the previous owner wired it this way because the sensor failed, and I don't have the cash for a new one for a week or so. Any suggestions appreciated thanks !!

 

Wire nuts are not for automotive use. Check your connections and wire in a relay if your going to control the fan remotely.

 

ozwin , when you saw how hot the toggle switches were getting that was a sign that your fan draws way too much power for the switch to handle . Similarly , from your description the contact in your ignition switch that was controlling the fan has also very likely vaporized , leaving me to wonder are ALL of the ignition key switch driven electrical devices working (wipers , heat/AC blower , radio , etc) ?

On the bottom left of this wiring diagram (1987 2.6 V6) is your fan wiring . As you see there isn't much to the circuit , and as such it should be fairly easy to chase down where power is , and isn't , and diagnose & repair the circuit to it's original functionality .

Like Tuned Performance said , In short , if you want to stop burning up switches you've gotta get the original relay switched circuit working again .

 

If it was wired so the fan relay's green with white stripe wire was grounded, that would have the fan always working with key on. Failure to continue working could be bad wiring, relay or failing fan motor. Check those things. Some people wired it that way because of a failed fan switch. Not a great fix but works in a pinch until you replace the fan switch.DO NOT try and wire the fan directly from the fuse box or any other 12 volt source.
As mentioned use a relay. Sounds like your switch was wired straight to a hot wire. REALLY bad idea
Good luck