Tweet
Ok, fan started not coming on couple weeks ago, right when my puter had committed ritual suicide so I couldnt come here and search.
I first started checking all the fuses, I pulled the turn signal fuse and fan came on and ran all the time plus as a bonus my turn signals then no longer worked. I put fuse back and temporarily ran wire to passenger compartment to manually turn fan on and off.
Figure has to be relay, cant find it, supposedly someplace behind left headlight, but dont see anything that looks like the replacement. Plus as a bonus the replacement is like $65. WTF, its a simple relay for pete's sake not a gold coin.
I get $5 generic 40A relay like one would use when you add fog lights or such. I wire it up making my own independent circuit. The trigger circuit goes between + on coil and grounded to fan switch. Fan runs all the time cold and I didnt even try it hot. Figure the switch has to be bad. But switch and relay going out at same time, seems highly unlikely. The engine is originally out of a 323 so hunt around and find the old 323 thermostat housing and take switch out of it. Finally it works right.
However after getting back online and looking at some posts here seems the original Festiva fan switch was probably still ok, it just is closed when cold, then opens up, and open solenoid in relay sends current via that 5th terminal. In other words when I turn the key on, the ignition coil is powered, which closes the solenoid in the relay, since the Festiva fan switch is closed when cold. Thus fan is off. When switch opens, it unpowers the solenoid and the relay goes to default position powering the fan on. The 323 fan switch for whatever reason is opposite and closes when coolant temp gets hot.
Have I got that right? Thus with OEM Festiva setup, the fan is on by default so if fan switch fails or the solenoid in the relay fails? But this also means fan hot wire that relay switches on and off to the fan has to also be only hot when ignition is on? Otherwise the relay would have to be powered with solenoid closed whether car is running or not and slowly drain the battery. I suppose one could combine two relays so first relay provides power to the second relay when ignition is on. Second relay by default powers the fan when solenoid is open.
Hmm, this maybe more failsafe but seems lot more complex. And not so failsafe if the first relay fails. Instead of two relays, about have to hook into a circuit that has enough capacity to power the fan, but that is on only when ignition is on. And I suppose thats how Festiva was designed, it gets power for fan from circuit that powers the turn signals which is a switched circuit that is only hot when key is on???
I see the logic obviously, but it wasnt so failsafe in my case, when relay failed, the fan did not come on constantly. Maybe some other wiring failed too? Not sure it wouldnt be about same difference at this point to wire in a manual over ride switch to the dash that if fan doesnt come on, you flip the manual switch to turn it on. Or just gamble. I mean the Festiva seems to have been designed so unless you really push it, in most circumstances the radiator tends to keep engine cool enough to prevent self destruction even without fan. I mean it took a bit for me discover fan wasnt coming on originally, first noticed coolant temp gauge showed higher temps than usual after driving up my steep hill. Then listened for the fan and didnt hear it. On some cars I would have fried the engine by this time.
I first started checking all the fuses, I pulled the turn signal fuse and fan came on and ran all the time plus as a bonus my turn signals then no longer worked. I put fuse back and temporarily ran wire to passenger compartment to manually turn fan on and off.
Figure has to be relay, cant find it, supposedly someplace behind left headlight, but dont see anything that looks like the replacement. Plus as a bonus the replacement is like $65. WTF, its a simple relay for pete's sake not a gold coin.
I get $5 generic 40A relay like one would use when you add fog lights or such. I wire it up making my own independent circuit. The trigger circuit goes between + on coil and grounded to fan switch. Fan runs all the time cold and I didnt even try it hot. Figure the switch has to be bad. But switch and relay going out at same time, seems highly unlikely. The engine is originally out of a 323 so hunt around and find the old 323 thermostat housing and take switch out of it. Finally it works right.
However after getting back online and looking at some posts here seems the original Festiva fan switch was probably still ok, it just is closed when cold, then opens up, and open solenoid in relay sends current via that 5th terminal. In other words when I turn the key on, the ignition coil is powered, which closes the solenoid in the relay, since the Festiva fan switch is closed when cold. Thus fan is off. When switch opens, it unpowers the solenoid and the relay goes to default position powering the fan on. The 323 fan switch for whatever reason is opposite and closes when coolant temp gets hot.
Have I got that right? Thus with OEM Festiva setup, the fan is on by default so if fan switch fails or the solenoid in the relay fails? But this also means fan hot wire that relay switches on and off to the fan has to also be only hot when ignition is on? Otherwise the relay would have to be powered with solenoid closed whether car is running or not and slowly drain the battery. I suppose one could combine two relays so first relay provides power to the second relay when ignition is on. Second relay by default powers the fan when solenoid is open.
Hmm, this maybe more failsafe but seems lot more complex. And not so failsafe if the first relay fails. Instead of two relays, about have to hook into a circuit that has enough capacity to power the fan, but that is on only when ignition is on. And I suppose thats how Festiva was designed, it gets power for fan from circuit that powers the turn signals which is a switched circuit that is only hot when key is on???
I see the logic obviously, but it wasnt so failsafe in my case, when relay failed, the fan did not come on constantly. Maybe some other wiring failed too? Not sure it wouldnt be about same difference at this point to wire in a manual over ride switch to the dash that if fan doesnt come on, you flip the manual switch to turn it on. Or just gamble. I mean the Festiva seems to have been designed so unless you really push it, in most circumstances the radiator tends to keep engine cool enough to prevent self destruction even without fan. I mean it took a bit for me discover fan wasnt coming on originally, first noticed coolant temp gauge showed higher temps than usual after driving up my steep hill. Then listened for the fan and didnt hear it. On some cars I would have fried the engine by this time.
Comment