Wiring radiator fan with an off-on switch?

[bobstad]

The radiator fan in my '91 Festiva 5-speed has never worked, which I didn't even notice the first couple of years I drove the car I bought June of '99. The fan itself is fine as I've tried it directly on the battery, but whatever wiring is in between must have problems and/or perhaps some device therein involved. Right now the fan itself is sitting on the floor under the driver's seat.

I've been very terrorised lately when caught in gridlock in some urban situation at rush hour or similarly on the freeway. I have to stop my engine every time the traffic halts to let the motor cool off a little, and recently was stuck on the bay bridge from Oakland to San Fran around six on a weekday evening when I took the wrong exit coming from the south...and feel lucky I didn't blow a head gasket.

I'd like to simpley wire my fan with an off/on switch so I'd never have to worry about anything but watching the temperature gauge; which is a habit I've gotten very observant about. Can anyone give me what is a safe, reliable approved method for doing this?

[b3 madness]

The problem with your fan is in the RADIATOR FAN TEMPERTURE CONTROL SWITCH. This is located in the thermostat housing and it completes the fan circuit to ground when the coolant temperature breaks the preset temp. They are around $30 new, but I got one for $2.50 at the JY.

[festivaWES]

Actually i thinks it located on the head itself....mine wasn't working either i just disconnected it and it turned on. So you could just unplug it or get a new sensor and wire a toggle switch off of that to your dash and have complete control of it.

[Ffaf]

If it has only recently started to overheat when you never used to have problems with it then there is something else wrong there somewhere. Start with flushing out the whole cooling system and fit a new thermostat. Also, the fan does work if it isn't connected to the thermostat housing so you can override the system to have it always on.

[htchbck]

put the key in and turn it to "on"... then unplug the little plug that goes into the t-stat that screws into the water neck. its is a blade type connecter. If the fan comes on when you unplug that, then the t-stat is your only problem. If it fails to come on, then there is a problem elsewhere in the system. If you're really worried about overheating and the fan is working properly with the plug disconnected, you can just leave it unplugged. I have an aspire water neck on my silver car and it doesn't have a hole for the t-stat to screw into, so I just capped the plug wire and let the fan run whenever the car is turned on. It still runs at normal temperature, heater works great, and I've never had a problem with overheating since I did that.

[Bowls]

Yeah htcback, but where you live it is probably warm, it might be cold where he lives, which would suck because festiva's have pretty wimpy heat. i only get the max setting and only the feet and defrost work, rest just blows cold air. i read the sticky on it, but i cant afford it right now so i wait till next winter

[htchbck]

^^^ you may be right about it being warmer here, the coldest its gotten lately have been the low 10s which is nothing compared to further north. And BTW, you'll never get any heat out of your front vents unless you completetly rework the entire airbox. The way the ducting is made its just not possible, I had mine apart not too long ago replacing the heater core, and I tried several methods of getting heat out the front... none worked... plenty of heat outta the floor and the defog though...

[bobstad]

Well, I do need to try to see if my only problem is the "t-stat" I assumn htchbck means is a thermostat. I have no great love of my fan being on all of the time, since this would be unecessary wear on its motor let alone superflous drain on the battery. The car always runs cool enough, except when not moving. The reason I never noticed the fan wasn't working is my driving had all been rural or freeway the first few years I owned the car. That is to say I was never in a city hence never got stuck immobile in traffic for any length of time.

By the way, some of those suggestions will be invaluable in the interum, so I can engage the fan all of the time temporarily when I have to be in slow or not moving traffic. Thanks again Festivites, for saving potential big-time bacon here on this end.(note to self, need to buy some goodies to support the site!)

I still think the fail safe solution is to wire my fan to a switch so I can monitor the temperature gauge and turn the thing on only when necessary.(I've already back-flushed the whole system and installed a higher capacity copper and brass radiator, due to leaks in the original and my more or less meticulous habits if I have the chance)

[floydiancomplex]

there are 3 temp sensors on the motor (1) up by fuel rail and injectors, this one tells the ECU the water temp. wire is Red/Blue
(2) on the front of the head this is the fan relay switch, wire is Grn/Yel
(3) on the thermostat housing (or right next to it) this is for the temp gauge on the dash, wire is Yel/Wht

the best way is to use both a manual switch and the temp switch that way you can run the fan when you want and if you forget
the temp switch can still turn it on. the easy way to do this is just spice into the Grn/Yel wire coming from the temp switch
run it to one side of a SPST switch and ground the other side. this method will also work if the temp switch is busted and it
simply performs the same function as the temp switch by grounding the relay.

and you must use a relay (unless you want to mount a light switch in your dash) the fan draws about 25 amps and will burn
out most auto switches.