Help with electric fan (please)

[sams87gn]

My electric fan does not go on anymore . If i am in traffic & the temp gets near 190-200 the fan does not come on . I have to get moving agin to bring the temps down. I do not drive the car much any more so i did not notice when the fan stoped working. But when i loosen the battery cable & take the bolt off the fan starts for a second. Is there a way to trouble shoot this? Thanks

 

[larry33kc]

Here ya go. Lots of info. http://www.vortexbuicks-etc.com/index.html

 

[groumoutis]

Try turning on your a/c and see if the fan comes on. It should be on high if it does come on. If your low speed relay is bad it will still work with the a/c since it will be going through the high speed relay. If the high speed works then try jumpering acrossed the resistor by the fan and see if it comes on without the a/c on. If it does work with the a/c on but doesn't work with the resistor jumpered it would more than likely be the low speed relay.

 

[williamsGN]

With mine it was an issue with the connector to the fan, I ended up hard wiring it.

 

[GWHIZZER]

With mine it was an issue with the connector to the fan, I ended up hard wiring it.

It could also be the coolant sensor that triggers the fan relay to come on. This sensor is located on the intake manifold
right alongside the throttle body -sticks straight up. Pull the cap off the sensor (green wire) and stick a wire into
the cap- then ground the other end of the wire to a throttle body bolt (key on). The fan should run. If it doesn't,
then most probably the relay is bad. If the fan does run, then most likely the sensor is bad. I just went through this.
-Hope that helps.

 

[groumoutis]

That is a temp sensor and it tells the ECM what the temp is and the chip tells the fans to kick on not the temp sensor.

 

[aminga]

That is a temp sensor and it tells the ECM what the temp is and the chip tells the fans to kick on not the temp sensor.

The one on the top of the intake is a switch and is not connected to the ECM. The only sensor connected to the ECM is the front of the intake on the drivers side.

 

[blackdeathtrap]

my car had same issue 2 years ago fan wouldnt comme on cheq wires that go to the starter there is a fusible link (one of the red wires) that go to fan relay this might be your issue

 

[sams87gn]

I think the resistor is bad I ran a jumper wire from the battery to the fan with key on the fan runs. Then disconneceted the resistor & hooked the wires together . And the fan will run when the temp hits 195 to 200 & when the temp drops to under 195 it stops. I unpluged both relays Then tried the low speed connector on both relays @ 195 degrees & the fan will run . But if i try with the high speed connector the fan will not run with either relay . So that means my relays are good but my hi speed connector is bad? ( By the way nothing worked untill i disconneceted the resistor & hooked the wires together )

 

[blackdeathtrap]

cheq if your getting power to the were the relays plug it cuz my car was doing the samething and my wire on my starter was fried

 

[sams87gn]

cheq if your getting power to the were the relays plug it cuz my car was doing the samething and my wire on my starter was fried

ok Thanks will check tommorw

 

[sams87gn]

Well i think i figured it out . The A/C in not charged so the fan will not run on high if the A/C is on . & The resistor was shot . So i hooked the wires together on the resistor & grounded the AC high pressure switch & the fan runs . I repalced the A/C compresor & other items But i have not had the system recharged yet . Does any body know where you can get a new fan resistor? or can i leave the wires hooked togeather . & thanks for all the help.

 

[williamsGN]

Leave out the resistor, most of us have as a first mod. It allows the fan to run on high speed instead of low speed, which is pretty much useless.

 

[GNRick]

The one on the top of the intake is a switch and is not connected to the ECM. The only sensor connected to the ECM is the front of the intake on the drivers side.

My car was running hot (200+) when the fans would come on, then fans shut off at about 195. I replaced that sensor on the front of the intake and now it stays at 190 or less. I think the sensor was sending a bad signal to the ecm.