fan always on ( even before starting the engine )

[yousufwalton]

Ok so i went out side today to try and figure this one out.

Unpluged the wire to the fan switch in the t-stat looked ok pluged it back in didn't do anything the fan still on as soon as the key is turned to aux even. unplugged the fuse and the fan don't come on. so yeah put the fuse back un plugged and plugged the thing back in again and well it still don't work its always on... could this be a stuck T-stat because even after or what else could it be? 10 mins of idle with no fan the engine temp gauge still was rock bottom.

[DriverOne]

Re: fan always on ( even before starting the engine )

The thermostatic switch may be bad. If you have buildup on it, sanding it may help.


The fan is supposed to come on as soon as there is power, if the switch says it needs it. Unplugging the fan from the switch defaults to on.

[25Horseplay]

Replace the fan switch, it's most likely bad. They are pricey though.

[blkfordsedan]

I believe the fan switch is normally closed, so when you pull the wire off it, the signal ground is broken and the relay turns the fan on. I guess if you pull the wire off and ground it, the fan should shut off....which would indicate a bad switch. If the fan remains on when the wire is grounded, then the relay is bad. At least that would make sense. You should also locate the relay and test the signal wire at the relay before replacing anything. My fan ran all the time as well and grounding the wire made no difference. Turns out the wire had a bad spot in it just before it plugs into the relay. The relay and switch were both good. If the wire itself is bad, then it will never have a signal ground to reference and the fan will run no matter what.

Be careful if/when you buy a switch. I'm not 100% sure, but I think the Festiva one (normally closed) is very hard to find and ones used in the Mazdas look identical but are normally open. I could be wrong...but I think the ones Rock Auto is selling for the Festiva are wrong.

[David88]

I had a problem with my L plus with the fan running at weird times. It would start and stop intermittently. Then it got to be the engine would just shut off and the fan would start. I could restart and it would sometime die right away. I figured out by wiggling the key that I had an ignition switch going bad. Replaced the switch with a good used one (thanks eurotiva) and no more issues.

[yousufwalton]

seems the easiest solution at least for the time being is to make a hard switch on the dash then.

[DriverOne]

Re: fan always on ( even before starting the engine )

It's fine just to leave it running. That way you'll never overheat. Otherwise, stop & go traffic will have you wearing out that switch.

[Movin]

Take the worn out ignition switch, the ancient relay, the questionable and somewhat costly thermal switch and possibly loose, corroded and old wiring out of the equation. Wire in a new adjustable radiator fan controller. Easy, all new except your fan itself and you can set the temps where you want them.

[yousufwalton]

It's fine just to leave it running. That way you'll never overheat. Otherwise, stop & go traffic will have you wearing out that switch.

Well yes except its winter for now, and the damn thing never even moves the temp. ( which could be the temp sensor i dunno )
and i would like it to warm up quicker.

Take the worn out ignition switch, the ancient relay, the questionable and somewhat costly thermal switch and possibly loose, corroded and old wiring out of the equation. Wire in a new adjustable radiator fan controller. Easy, all new except your fan itself and you can set the temps where you want them.

what is this magic you speak of. ( one thing i hate is electrical lol )




In all seriousness. Whats the easiest way to put the switch on there ( the flip/push-button ) one until i get around to doing the real solution.

[Bert]

Ok so i went out side today to try and figure this one out.

Unpluged the wire to the fan switch in the t-stat looked ok pluged it back in didn't do anything the fan still on as soon as the key is turned to aux even. unplugged the fuse and the fan don't come on. so yeah put the fuse back un plugged and plugged the thing back in again and well it still don't work its always on... could this be a stuck T-stat because even after or what else could it be? 10 mins of idle with no fan the engine temp gauge still was rock bottom.

The fan circuit thermosensor is not located right in the thermo housing, it's in the block. Is there a chance you're playing with the dash temp sending unit?