So I just purchased a used 2004 Toyota Corolla LE with 226k miles on it. I knew the AC wasn't working when I purchased it. I've watched a bunch of youtube videos that talk about replacing the relay with the horn relay to see if it kicks in, but in all the videos they say the radiator fan works. Mine isn't spinning. Now the guy at the local auto parts store said that if the fan isn't spinning usually the AC wont work. I don't know if that is legit or not.
I watched one of Scotty's videos on the radiator fan and was able to take to jumper wires and hook them up to the battery and to the back of the fan. Fan spun so I know the motor in the fan is good. I did replace the relay for Fan 1 and it did nothing. I need to get a relay for Fan 2 (altho I only see 1 fan in the car so I'm not sure what Fan 2 relay is for). I also checked the RDI Fan 30amp fuse which seemed to be good. The only thing I haven't done is check the cooling fan temperture switch. In Scotty's video it says to hook up a jumper to the contact for the cooling switch and connect it to the ground. I am somewhat confused on this, should the car be on or off? Should there be a positive connected somewhere?
If it ends up not being the tempurture cooling switch or the Fan 2 relay any ideas on what I'm looking at here? Also, could the Radiator Fan be why the AC doesn't work or is that a seperate issue all together. Its really hot here in the summer and I'd like to get the ac working so I can take my dog with me places, dog has more fur than a fur coat store so until the ac works he has to stay home.
Thanks guys.
Yes, the cooling fan should turn on when the engine gets somewhere between 200 degrees and 220 degrees no matter if the AC is working or not.
The easiest way to see if that's happening is to hook up a scanner (any cheap $35 scanner will do) and go to Live Data and look at the ECT Sensor reading.
You didn't complain that the car is overheating. Maybe the thermostat is stuck open and the engine isn't getting hot enough.
The fan is controlled by the computer using a voltage signal input from the ECT sensor and/or the AC controls. The ECT sensor is a thermistor circuit and in your case the lower the voltage = lower resistance = higher temperature.
It looks like this:
If you want to try to fool the computer into thinking the engine is hot and to kick on the fan you can disconnect the ECT Sensor wiring connector and jump the two terminals with a paperclip or a piece of wire and then turn the ignition switch to the ON position.
If you have a scanner you'll also see the ECT Sensor go to over 280 degrees.
If the fan still doesn't kick on then you can test the rest of the circuit:
Since you asked, the FAN 2 relay is how the fan speed is controlled through the Ground Side of the Cooling Fan Motor.
Anyway here's the system description and the wiring diagram.
You can grab a test light and test for Power (always) at FAN 1 relay socket terminal 5 from the 30A RDI Fan Fuse.
Then test for Power (KEY ON) at FAN 1 relay socket terminal 1 from the 10A ECU-IG Fuse.
If you have Power to both you can grab a paperclip or a small piece of wire and jump Fan 1 Relay Sockets 5 & 3 and the fan should run at low speed.
Here's the Relay Socket location and terminal number map:
Usually the way the fans are set up they will turn on with the compressor. Have you hooked up a manifold gauge set to see if there is enough pressure for the compressor to engage?
So you are saying the radiator fan not coming on at all is not related to the AC.
That is correct. The fan should work either when the coolant temperature gets to a certain level or when the AC compressor turns on. (Actually it's not clear from your initial post whether the compressor is switching on or not.)
You've determined that the fan itself works. Next you'll want to check the temperature sensor that triggers the fan. I am not familiar with your car but on most I've seen if that sensor has two wires the fan(s) should run if those are jumpered together. You'd want to verify that's the way the sensor works of course, you don't want to damage anything. (I've never worked on a car as new as yours.) Beyond that it would be time to get out a wiring diagram and trace out the circuitry to find the fault.
Or, you could elect to put in a new fused circuit with a manual switch for the fan as Scotty has demonstrated in his videos.
I do not have a manifold gauge. Never even heard of one. But I do know a while back we did check to see if it was low on coolant and the guy at the oil change place had said it had coolant and the pressure was good. Not sure if that's the same thing or not. Also, isn't the fan supposed to kick on if the engine is getting hot regardless of the AC?
I do not have a manifold gauge. Never even heard of one.
In that case it would be best to have the AC checked by an expert. It's all too easy to make things worse or even injure yourself without the proper tools and experience. Seeing as how you're dealing with a 20-year-old car it is quite likely at least some of the refrigerant has leaked out.
But I do know a while back we did check to see if it was low on coolant and the guy at the oil change place had said it had coolant and the pressure was good.
Guys at "oil change places" are not real mechanics or qualified AC technicians. You're lucky if they don't damage your car while doing a simple oil change. If there is enough pressure in the system (who knows what "the guy" actually did) you may have a bad low pressure cutoff sensor, but that would need to be diagnosed. What you want is not a dealer, not a chain shop (stay away from Pep Boys, Midas, Firestone, etc.), and not a quick lube joint - look for a good independent shop in your area.
Also, isn't the fan supposed to kick on if the engine is getting hot regardless of the AC?
Yes, but that's a different issue than the AC not working.
So you are saying the radiator fan not coming on at all is not related to the AC. Can you comment on the steps I took troubleshooting the radiator fan and the question about testing the cooling fan temp switch.
The easiest way to see if that's happening is to hook up a scanner (any cheap $35 scanner will do) and go to Live Data and look at the ECT Sensor reading.
Looking at amazon they have ODBII scanners would this be the correct type of scanner you are talking about?
You didn't complain that the car is overheating. Maybe the thermostat is stuck open and the engine isn't getting hot enough
Correct, the car isn't overheating, sitting about midway between cool and hot on the temp gauge.
You can grab a test light and test for Power (always) at FAN 1 relay socket terminal 5 from the 30A RDI Fan Fuse.
Does this mean take the test light and stick it in the Fan 1 relay term 5? not sure what "From the 30a RDI fan fuse means
And where are you finding these diagrams at because they are very helpful.
Yes on the scanner. Here's an inexpensive one that sells on Amazon:
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https://www.youtube.com/watch?v=SviDQqjDjgA
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If the car isn't overheating and the cooling fan isn't working make sure you check the coolant level to make sure it's full. If it is then the thermostat may be stuck open. But with a scanner you'll see the actual Coolant Temperature from the ECT data
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If you look at the wiring diagram I posted you see that Power going to the Fan 1 Relay terminal 5 comes from the 30 amp RDI Fuse. (I'll circle the Fuse and highlight the circuit from the Fuse to FAN Relay 1, terminal 5
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You won't stick the test light probe into terminal 5 because you could spread apart the terminal. You'll remove the FAN 1 relay and then connect the test light's alligator clip to the battery negative post and then touch the test light's probe to terminal 5. And then again, this time with KEY ON, to terminal 1.
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Here's an explanation of relays and how to test their socket terminals and how to jump the Load Side of the relay with a piece of wire:
https://www.youtube.com/watch?v=xiaqTfl2ZZE
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I got the diagrams just by searching Google
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Here's one search result. You can find others
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https://www.tcorolla.net/toyota_corolla_repair_manual-422.html
If the car isn't overheating and the cooling fan isn't working make sure you check the coolant level to make sure it's full. If it is then the thermostat may be stuck open. But with a scanner you'll see the actual Coolant Temperature from the ECT data
On this so I'm not sure what coolant to put in, Asian Red / Pink or the normal peak / prestone 50/50. Not sure how to tell whats inside, was thinking about just draining the fluid and putting new fluid in and dont want to put in green if it has the red / pink or vise versa, but on 226k miles should i just leave it alone as far as draining it completely and putting new coolant in?
And thanks for all the info so far, money is really tight so going to a shop and paying a few hundred bucks just to find out what's wrong is not really an option at the moment.
On this so I'm not sure what coolant to put in, Asian Red / Pink or the normal peak / prestone 50/50.
If you completely and thoroughly flush out the cooling system you can put whatever coolant you want in it. Best for that car would probably be the "Asian red" type.
If you just want to top it up you need to figure out what's already in there since some coolants don't mix well. Bear in mind the color is only a dye and not a guarantee of coolant type.
I just ordered a Bluedriver Bluetooth Pro hopefully it can provide some answers. As well as a test light circuit tester.
If you have Power to both you can grab a paperclip or a small piece of wire and jump Fan 1 Relay Sockets 5 & 3 and the fan should run at low speed.
So this worked jumping 5 and 3 turned the fan on. However It doesn't turn on on its own, let the care idle for about 15min with the horn relay in its place and it never turned on. So I know its not a bad relay.
If you want to try to fool the computer into thinking the engine is hot and to kick on the fan you can disconnect the ECT Sensor wiring connector and jump the two terminals with a paperclip or a piece of wire and then turn the ignition switch to the ON position.
The computer should provide a Ground to FAN 1 relay socket 2 to energize the relay and the fan should run.
