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Toyota Service
Toyota Service, Toyota Expert
Category: Toyota
Satisfied Customers: 4597
Experience:  30+ Yrs of auto experience, Award Winning Svc. Manager; Just Answer Customer's Choice Award Winner
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I have a 2001 Corolla. Its a CE 1ZZFe 3 speed auto. Neither

Customer Question

Hello,
I have a 2001 Corolla. Its a CE 1ZZFe 3 speed auto.
Neither of the cooling fans will work. With or without AC on.
We checked the fuses, we checked the Relay.
We unplugged the temp sensor under the intake manifold ant he one on the side of the block.
We jumped the fan to see if it was dead, it ran fine.
Were stumped. Did I read somewhere that the ECM may have some control over the fans?
Thanks, AJ
Submitted: 1 year ago.
Category: Toyota
Expert:  Toyota Service replied 1 year ago.

Hello. Welcome to Just Answer. Please allow me to assist you. The ECM does have a bit to do with the cooling fan operation, but that is only for the AC part of the system. I believe I can assist you, if you have the means to test for power and continuity. We need to check a few things to lead us down the right path to a cure. Can you do this?

Customer: replied 1 year ago.
but not at the moment as the car is at my moms. Bit tell me what to test and well go form there.
Thanks.
Expert:  Toyota Service replied 1 year ago.

Let's check main power first: Under the hood, in the fuse panel, there is a 30 amp fuse right next to the horn relay. it is labeled "RDI" on the label under the lid of the fuse panel, look to see if this fuse is blown. This is the main power for the radiator fan. Then in the smaller fuse panel under the hood (the one with 4 relays and 4 fuses) look to see if the 30 amp "CDS" fuse is blown. Then get back to me thanks

Customer: replied 1 year ago.
The fuses are good. Whats next?
Expert:  Toyota Service replied 1 year ago.

Pull out the FAN No 1 relay fom its socket. . Test for power with the key ON. You should have power in 2 of the 4 sockets.

Customer: replied 1 year ago.
OKay, so we checked it. WIth the key on, only power to the top lug.
With the car running, there is power to the top and bottom lug.
Expert:  Toyota Service replied 1 year ago.

Thanks. Does the AC work properly?

Customer: replied 1 year ago.
I can hear the ac kick on, but we don't run it very long as the car gets hot and no fans are running.
Expert:  Toyota Service replied 1 year ago.

There is a critical circuit that must be satisfied by proper AC system pressure. If the AC works, the AC single pressure circuit is OK. The ECU sends a ground circuit thru the AC single pressure sensor, This ground is then sent to the coil side of the relay you just tested. Since you have 2 places with power, it is safe to say that the Fan motor relay is not getting the ground it needs to energize the coil If you locate the AC pressure switch on the AC refrigerant lines, and remove the connector, look for a Blue wire with a black stripe. If you apply a ground (from the battery negative terminal, as a temporary test, and the fan runs (key on), you probably need an ECU

Customer: replied 1 year ago.
OK, so his could cause neither fan to operate? If we replace the ECU, will it need to be programmed byt he dealer?
And when you say ECU, do you mean the ECM? That's the one that's under the glove box?
Expert:  Toyota Service replied 1 year ago.

ECU/ECM same thing. different names. 2001 Corollas do not need to be programmed. Before you spend the money on a new ECU, it would be really a good idea to let a Toyota tech go thru this system with the wire diagram book in his hand to make sure that all of the ground circuits are OK.

Expert:  Toyota Service replied 1 year ago.

Let's do one additional test, ok? With the car running, and the AC on, disconnect the wire going to the radi fan motor. See if you have power in the Black with a red stripe wire. If you do, the system is working OK on that side of the circuitry. If the fan is not running, see if the White with a black stripe wire has direct continuity to ground.

Customer: replied 1 year ago.
How many ground circuits can there be? Isn't the only ground the one that is provide by the temp sensor?
I can see the AC circuit being its own, but wouldn't the main fan need only one ground'?
Customer: replied 1 year ago.
Which fan, or either?
Expert:  Toyota Service replied 1 year ago.

The main fan

Customer: replied 1 year ago.
OK thanks, ***** ***** those 2 tests and see where it goes.
Expert:  Toyota Service replied 1 year ago.

The AC fan power wire is Blue with a red stripe; that is how you tell which is which

Customer: replied 1 year ago.
No the fan did not turn on with direct ground, key on etc. when I connected wire I heard the relay click...The second test had no power to red and black wire...ground is ok.
Expert:  Toyota Service replied 1 year ago.

Do you have a meter that will check continuity?

Customer: replied 1 year ago.
Expert:  Toyota Service replied 1 year ago.

Please do the following. Remove FAN No.1 Relay completely from its socket. Disconnect the connector to the main cooling fan. Take one of the meter leads and attach it to the Black & Red wire on the harness side of the fan motor wire connector. Place the other lead in each of the 4 sockets from the removed relay. When you see continuity, let me know. We have another test right after that

Customer: replied 1 year ago.
OK, that test will be tomorrow, thanks.
Expert:  Toyota Service replied 1 year ago.

ok

Customer: replied 1 year ago.
With or without the key on?
Expert:  Toyota Service replied 1 year ago.

Key off/ After you find continunity, locate which socket had power (key on now). then take a wire form the socket that has power and manually jump that power into the socket you have continumity to the fan motor wire. Reconnect the fan motor connection and see if the fan runs.