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1997 Sunfire radiator fan not working

Dano1971 Dano1971
New User | Posts: 1 | Joined: 03/10
Posted: 03/07/10
04:53 PM

The radiator fan in my 1997 Sunfire doesn't come on. I've checked the fuse under the hood and the relay by it. When you jumper the plugs where the relay goes the fan runs. I don't think it's the coolant temperature sensor because the gauge in the car still works. Anyone have any sugestions?  

waynep7122 waynep7122
Addict | Posts: 4545 | Joined: 08/09
Posted: 03/07/10
07:49 PM

the radiator cooling fan is controlled by the ecm... and looks at the engine coolant temp via the 2 wire sensor ...

you can plug in a scan tool .. look at the live data and see how hot the engine coolant temp (ECT) displays on the scan tool...

most gms have the cooling fans cycle on at 215F to 238....     most between 215F and 228F..

if you unplug the engine coolant temp sensor.. the cooling fans are usually commanded on...

if someone has removed the thermostat... or it has broken...  the engine coolant temp will take forever to get hot enough to cycle the fan on..  but when it gets hot.. it will tend to overheat...

be sure to check the coolant level... as low coolant levels will give the ECT sensor a false reading..

here is the wiring diagram for the ecm of the 2.2 model...

here is the cooling fan control wiring diagram...

what happens when you remove the relay from the box and close the contacts manually???? does the cooling fan run>????

warning.. be careful not to probe the wire to the ECM.. it blows the circuit in the ecm if your test light pulls any where near an amp..  

jgate-#002 jgate-#002
Guru | Posts: 953 | Joined: 06/07
Posted: 03/08/10
10:38 AM

On a 97 Sunfire 2.2, you have two sensors,
one is a coolant temp sensor , that the signal is sent to the temp gauge, in the instrument panel.
And one that is called engine temp sensor, and this one sends it signal to the PCM were it is sent to ground and completes the circuit to the coolant fan relay.

coolant temp sensor
Part: ECH TS4052  
Product Line: Echlin Ignition
List Price 30.51

engine temp sensor

Part: ECH TS4015  
Product Line: Echlin Ignition
List Price 36.90  

Bonesaw Bonesaw
New User | Posts: 2 | Joined: 08/10
Posted: 08/06/10
10:31 PM

My 1997 pontiac sunfire 2.2L engine gets hot because the radiator cooling fan does not come on_does anybody know why????  

Bonesaw Bonesaw
New User | Posts: 2 | Joined: 08/10
Posted: 08/06/10
10:35 PM

Who can help me with my 97 pontiac sunfire radiator cooling fan not coming on??? i have checked the fuss and put a new relay in it and also tried unplugging the coolant temperature sensor and waited 10 to 20 seconds and it did not come on_please help me someone???  

waynep7122 waynep7122
Addict | Posts: 4545 | Joined: 08/09
Posted: 08/07/10
05:54 AM

do you still have the old relay you removed....     pry the cover off....

plug it back in...   push the contacts closed with the top of  screw driver.. or just squeeze them with your fingers if you can reach them..   does the fan then come on.....  that proves the power wires to the fan and the fan motor are good....

is your cooling system filled with coolant...   50% to 70% coolant..       is there a 192F thermostat...

is the thermostat installed and can your verify  its operation????

does the system hold pressure..

some of these motors have bleeder screws in the cooling system around the motor to let trapped air out of the cooling system.. you did not say which of the 2 motors you have in your car.. the single overhead cam version.. or the dual overhead cam 2.4 motor..

do you have a scan tool...   or a hand held infrared thermometer..  a digital volt meter...  your 97 is OBD2 so scan tools are available to see if the computer is getting the proper signals from the sensors..

i did post the wiring diagrams above... you will have to copy and paste the links to view then print them..

when the engine temp comes up to the programmed temp...  the ecm is monitoring the temp...  at programmed temps.. the ecm turns the cooling fan on by connecting the control wire to ground to complete the circuit in the relay and close the contacts...  this sends power to the cooling fans...  

jinxedd9 jinxedd9
New User | Posts: 1 | Joined: 12/10
Posted: 12/14/10
10:49 AM

cooling fan not coming on. 2001 2.2- temp gage was pinned at 260, relpaced thermostat (180 degree)car idle temp is approx 207 degrees (2 lines above 195) Shouldn't it be 180 ? I bled air from system, relays an fuse ok,should I replace engine temp sensor next since gauge inside working?  

waynep7122 waynep7122
Addict | Posts: 4545 | Joined: 08/09
Posted: 12/14/10
01:16 PM

this is a picture of the bottom of the cooling fan relay... they cost about 10 to 15 bucks at the parts stores...

you will have to identify which one it is by looking at your owners manual... or the labels inside the relay box cover.. its probably under the hood...

if you look carefully at this picture.. you will notice 2 tabs along the inside of the outer case on the left and right..

you can gently pry those tabs out and slip the relay out of its cover..   you can then plug the relay back in..   give it a squeeze and see if the fans cycle on at that point...

you will also notice that there are 5 numbers next to the terminals on the bottom of the relay...



pins 85 and 86 are the coil windings... that the computer controls to activate the relay...

pin 30 usually has the power for the radiator fan motor..

pin 87  usually has the switched power that feeds the radiator cooling fan motor...

it is vitally important NOT to go probing the relay box without knowing which ones you are probing..  

if you pry the cover off the relay...  you can test the fans in just a few minutes...

relays fail more often that the other parts of the system... so start there...  you can even clean the contacts when you remove the cover..  

if you probe connectors in the relay box... 85 or 86...   there is a chance of burning out the computer... so be careful.... squeezing the relay... won't hurt anything... //  

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