The coolant sensor controls these fans,one is for moderate cooling,the other kicks in when the temp gets up higher,so change the coolant sensor.Turn the ac on max cool,see if the cooling fans both come on,and let me know.
Well your coolant temp sensor/ sender is what tells it to turn on but that shouldnt be the prob. i would test the connection when the fan is running chances are the motor isnt getting a good connection. or the motor is bad.
First when you remove the cooling fan relays take a close look at the terminals where the relays go into and make sure they are not corroded and make sure they are making good contact on the terminals.Also you can remove the fuse and relay holder and look underneath where the wiring is and make sure all is good there to.Do the same on the with the fans make sure the terminals are making good contact with the fan motor terminals.The other thing is if you are just swapping the relays you could be moving the bad one from one spot to another.Might have to replace them with new ones.Some times if you wiggle them around you can tell which one is giving you the problem.If you know how to use a digital multimeter you can ohm the wires that go to the fans.Try this and let me know if you need more help.Good luck.
The fans are controlled by the pcm which gets it`s info from the coolant sensor.You can check the connections on the coolant sensor.I forgot to ask what motor you have.The 3.1 or the 3.8?The coolant sensor has black and yellow wire connector.Also check the grounds and make sure they are clean.One thing you could try if you think the motor might be the problem is use a fused jumper and a ground from the battery to the motor that does not work.Use the fuse on the positive side wire.If the motor does not come on then you know it is the motor.If it does come on then you know the motor is good.Make sure and check under the fuse relay center and make sure the wires do not look green and corroded.One other thing is it could be the pcm.Powertrain control module.
Yes it can still work because the fans work off of all 3 relays.Check the fuse for the cooling fan that is not working and make sure it did not blow.The PCM controls the ground circuit for the cooling fans from info from the temperature sensor.Depending on the temperature of the coolant the PCM could turn the fans on low or hi speed.The other thing with the relays is the ones that you swapped.Were they exactly the same as the ones that you took off?G.M.uses different relays on there vehicles.If the numbers on the relays were not the same then this could not have been a good thing to try.What a technician would do first is install a scan tool and then command the fans on with the scan tool and make sure the fans are good.The other thing he can do with the scan tool is drive the vehicle and see at what temp.the engine starts to get hot and also see if the fans are coming on at the specified temp.Then he checks to see if there are any codes in the cooling system.This way if there are any codes they will usually lead you to the problem or the area of the problem.Then he also checks for loose,or corroded wires or connections.It`s not always easy to help people because you don`t how much they can do or if they know how to use for example a test light,or multimeter,install a fused jumper wire or if they have the availability of a scan tool and know how to use it.
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I'm pretty sure it is not the fan motor connections. I originally thought the fan motor was out on the passenger side but when I switched out the relays, the passenger side fan came on when I turned the AC on and when the engine got hot.
Before I originally switched them, the driver side fan worked and the passenger side did not work. Then when I switched them, the passenger side worked and the driver side did not work. No matter how many times I switched them back and forth, the driver side still will not work at all now and only the passenger side works now. I switched the two 4 pin relays out with 2 that do work from the fuse boxes inside the car and nothing has changed.
Could the 5 pin control relay in the middle be bad and still let one of the fans work?
Is it possible some of the sensors could be out that tell the fans to come on when the engine gets hot?
It's a 3.8 V6. Did you get my last response with the questions about the fans? I was wondering if one of the fans would still work if the 5 pin control relay was not working.
I know it's not the fan motors. It has to either be the connections on the fuse box or the 5 pin control relay. Yes, the relays I switched out had the same number on them, 3604 I think. I got a 5 pin relay last night, 3602 I think but they gave me the wrong one, so I need to take it back tonight and I will let you know how that works.
I replaced the 5 pin relay and no change. I took the plastic cover off of the motor and I saw fresh coolant on the motor near the thermostat so it looks like I'm going to have to replace the head gasket, thermostat and flush the radiator. Any idea what a reasonable price would be to do this on a 2001 Monte Carlo SS 3.8? Doesn't look like there is too much to take apart to get the the head cover off on this motor but it would be nice to know what a fair price would be.
If the coolant is fresh, would this be coming from the thermostat or some other source? It does appear that there is some sludge coming from the head cover gasket but very little, mostly fresh coolant. I have not had any oil stains in the driveway so I'm thinking it is a small leak.
If I replace the head gasket, thermostat and flush the radiator, is it possible I can use the green coolant instead of the Dex-Cool? This seems to be an issue on GM vehicles.
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