fan constently running

[91blufestiva]

My car, 1991 EFI 5spd, the fan runs nonstop, except for when I have the key off of course, but once I get it running, the fan is always running. What's wrong? Could this be a reason on why my car barely ever gets past the first temp mark on my gauge?

[sasquatch]

there is two sensorn in the head by the water outlet going in to the rad, one round and one flat plug... take the flat plug and wiggle it if that dosnt fix it try and check the "meter" fuse in the box under the dash...

and im not to sure if this is right so someone may want to just make sure that this is right... if you take the wire off the flat plug and ground it, it should stop the fan... if that happens the sensor if in need of replacing...

[sanjeet]

I have a carbed 1992 Festiva and the fan relay is active when the ign key is on, the 1992 has an engine probe that is normally closed on the relay ground circuit, the engine probe opens when the engine is hot and switches the relay off turning on the fan.
[1] Could be a burnt relay contact sticking on.
[2] Could be a faulty probe in the engine block ( I tested mine in the oven and it should open circuit around 100 + degree's Celsius (212 F).

Your EFI may have more complicated circuitry than the basic Carb models, I have found with fans that don't work the owners will bypass the controls and that can be relatively common on older models in NZ

[blkfordsedan]

I believe the sensor side of the relay is normally energized which holds the contacts on the fan side of the relay open (which keeps the fan off). When the engine reaches the predetermined temp the fan temp sensor breaks ground, tuning the sensor side of the relay off, which lets the contacts on the fan side of the relay close and turn the fan on.
That's why when you unplug the fan temp sensor wire on a cold engine the fan should come on. You should be able to test the sensor with an Ohm meter set on continuity. With the sensor cold, you should have continuity between the wire terminal and the body of the sensor. If you do and the fan is running, you have a bad or stuck relay. If you do not have continuity on a cold sensor, then the sensor is bad. More than likely, the relay is bad.
My '93 has the same problem. I just unplugged the fan so it would warm up in the winter. Drove all last summer (90F - 100F) and winter with the fan unplugged and the temp never got more than just over half gauge. Several times I even forgot I let it idle outside for over an hour. If the thermostat ever sticks, however, I'll have a crispy engine. I can always pop the hood and plug the fan in if I catch it in time. It's on my list of things to fix when the weather warms up!