Car cooling fans not coming on?

Question

1999 grand prix 3100 series v6 - switched out the 2 cooling fan relays, drove around for an hour, pulled over open hood cooling fans still not running/turning? what can i do to fix it.

Answer 1

Check the coolant temperature switch. It's what turns the fans on and off. It is usually located on the thermostat housing.

Answer 2

what u can do is hook a wire 2 the fan and run it 2 the wire harness for the ignition (under hood) use a wire tester 2 find the one that works with the key!!!!!

Answer 3

If and engine has its thermostat locked open, it may never reach normal operating temperature.  Never run an engine without a thermostat.  Some engines can even overheat without a thermostat because the coolant can move through the radiator so quickly that not enough heat transfer takes place.  Most of the time though, the engine will not get as hot as it should, which causes other problems like fouling of plugs, combustion chambers, O2 sensors, and catalytic converters, poor fuel economy, and more.

Is the check engine light coming on?  If not, you may not have a problem.

If you were driving, pulled over, and immediately opened the hood, the fans may not need to be running.  The fans come on when a sensor, that is in intimate contact with the engine coolant, reaches the temperature that the manufacturer decided should be the temp. that the fans come on.  If you are driving at more than about 20 mph or so, the fans will probably never come on.  Unless you  are really pushing the engine.

To test the fans, just let the car idle.  It won't be getting any air flow through the radiator and will heat up.  Watch the temperature gage and as it climbs past the normal range, the fans should come on.  Actually only one fan will probably come on.  The other fan is probably wired to the AC system and doesn't come on unless the AC is on.  If you don't have a temperature gage, don't do this test.  You won't know if you are over heating your engine just waiting for the fan to come on.

The temp. sensor could be faulty.  This can be tested by removing it form the engine, placing the brass end in a pot of water, putting an Ohm meter across the two leads or across the one lead and the brass body, putting the pot over a flame and watching the Ohm meter change with temperature.  It should have a linear relationship between temp. and resistance.  An auto parts store or the internet may be a source for finding out what the resistance range should be.  Or just replace it if testing it is too involved.

Let us know what happens.

Answer 4

Why did you replace the fans?  Were they getting power or did you even check that?  Did you check the fuse and the relay?  A siezed fan motor can blow the fuse (had 2 of those in the shop just this week) and if you don't replace that fuse no amount of new fans are going to ever turn on.

How about the switch?  

Answer 5

very common problem not so easy answer many people just run jumper wire off the battery (+) to a switch inside and then to the fan(s) if you dont like this idea but dont wanna pay a mechanic get ready to lose your hair  try the fuse if vthat dont work hook the fans stright to the battery to see if there any goodif there good check temp sending unit