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My first post yea! I bought a used car yesterday and noticed the cooling fan is always on even if the coolant is low and the A/C compressor isn’t connected so I now that isn’t it. So here’s the problem but the cooling fan never turns on when I disconnect temperature sensor going to ECM. BTW the ground for the fan is connected to a 30 A HVAC blower fuse, it was like this when I bought it.
The car is a 1998 Chrysler Concorde.
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Here is a sight for a wiring diagram.
The quick fix for fan control problems is to wire the fan so that it runs all of the time. I suspect that is what has happened here.
[quote=”barneyb” post=105701]The quick fix for fan control problems is to wire the fan so that it runs all of the time. I suspect that is what has happened here.[/quote]
You’re right, the fans didn’t turn on when I disconnected the coolant temperature sensor. I’ve checked the wires and they’re all good and I’m guessing the relay works because it turns on when the yellow wire is connected to power, but maybe I’m wrong? Is there anything bad about keeping the fan on 24/7? BTW the site doesn’t have the diagram I need thanks anyways!
What’s bad about the fan running all of the time? Some people hate the noise. The fan will wear out sooner. You will take a tiny hit in gas mileage. Hmmm – still searching for a good reason not to do this.
[quote=”barneyb” post=105717]What’s bad about the fan running all of the time? Some people hate the noise. The fan will wear out sooner. You will take a tiny hit in gas mileage. Hmmm – still searching for a good reason not to do this.[/quote]
I didn’t do it, who ever worked on the car before did it. When I disconnected his wire the fan wouldn’t switch when the CTS is disconnected so something is wrong. I’ll fix it when I have the money to fix it, what’s odd is there are no codes stored related to that issue.
Obviously, we know that the fans are working. It sounds like you have tried sending power to the relay, and that is indeed switching the fans on. The next steps would be to test the wire that runs from the ECM to the relay for continuity, and also the wire(s) that go to the CTS. If all those wires have continuity, then the only other components in the system are the temperature sensor, which you can test using a multimeter, and a pot of water on your stove. If the wiring all shows continuity, and the CTS passes the test, then about the only thing left is the ECM.
I’m not going to say that this is typical, but sometimes the fan control built into the ECM just fails. As long as everything else related to the ECM appears to be working properly, and the only thing that has issues is the fan control, you can get a stand alone, aftermarket fan controller (typically sold for race cars, but you can generally find them at the big auto stores like Auto Zone, and Advance Auto etc.) and set that up to turn your fans on and off. If you pick the right control, it can even be used to switch your fans on and off when you turn the A/C on. The cost of one of these controllers is typically under $50, a whole lot less expensive than replacing an ECM.
As pointed out you know the fan, relay, and wiring are good. The issue is control. To diagnose it you’re going to need some info, namely a wiring diagram. The link that College man posted should help you with that. Once you have the diagram we’ll be able to help you figure out why the fan is running all the time. In the mean time you might want to check and see if someone wired it up to work all the time as suggested. If this is the case, then you should disable that and find out the real reason the fan is not working properly. More info on electrical issues here.
http://www.ericthecarguy.com/faq/solving-automotive-electrical-problems
Good luck and keep us posted.
[quote=”Tomh” post=105820]Obviously, we know that the fans are working. It sounds like you have tried sending power to the relay, and that is indeed switching the fans on. The next steps would be to test the wire that runs from the ECM to the relay for continuity, and also the wire(s) that go to the CTS. If all those wires have continuity, then the only other components in the system are the temperature sensor, which you can test using a multimeter, and a pot of water on your stove. If the wiring all shows continuity, and the CTS passes the test, then about the only thing left is the ECM.
I’m not going to say that this is typical, but sometimes the fan control built into the ECM just fails. As long as everything else related to the ECM appears to be working properly, and the only thing that has issues is the fan control, you can get a stand alone, aftermarket fan controller (typically sold for race cars, but you can generally find them at the big auto stores like Auto Zone, and Advance Auto etc.) and set that up to turn your fans on and off. If you pick the right control, it can even be used to switch your fans on and off when you turn the A/C on. The cost of one of these controllers is typically under $50, a whole lot less expensive than replacing an ECM.[/quote]
No one of the wires is connected to a blower motor fuse, one thing I’ve noticed is after the car gets to a certain point on the gauge I hear a relay click but the fan speed doesn’t change. However when I disconnect the wire from the fuse box the relay never clicks? The relay connectors are getting power though. The car is not overheating.
Good news guys my uncle recommended that I replace the relay, so I did and now the fan turns off and turns on when needed! Thanks guys for the help.
That sounds like a fix! Thanks for the update and for using the ETCG forum. Stop back if you need us again.
[quote=”EricTheCarGuy” post=106340]That sounds like a fix! Thanks for the update and for using the ETCG forum. Stop back if you need us again.[/quote]
Will do! Your videos have helped so much with working on my car 🙂
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