3sfe Cooling fan not turning on - please help!

[Rogue10186]

Happy New Year!

Ok, heres the problem, the radiator fans on my 91 camry w/ the 3sfe 4cyl have just started not working. The car seems fine when on the interstate, however as soon as I hit traffic it has started overheating because the fans wont turn on. They both spin freely, and It looks like everything is connected. I also checked the fuses, and they were ok.

I checked the engine codes and only got code 43, also the fans didnt turn on when I turned the AC on, however, I only ran it w/ AC for a few minutes... Can someone please help me out?

I need to drive back to my apt tommorow for work on tuesday, so if worse comes to worse, is it possible to wire the fans dirctly to the battery or something that will have them run all the time?

Please help!

[toyomoho]

Check RDI and FL CDS Fan fuses. The system is designed to failsafe. If something fails or a wire breaks the fans should keep running. Find the service manual for this year/engine type at the link below and dig out the wiring diagram. The usually problem is the coolant temp sensor that controls the radiator fan but since both fans don’t work, not sure.

If you cannot solve the problem before driving home. Pull the power plug going to the radiator fan and apply 12V DC directly. The radiator fan has Blue (+) and White/Black (-) wires running to it. The A/C fan has White (+) and Red (-) wire running to it. Once power is applied, recheck the direction of the fan rotation to make sure it is pulling air in from the radiator. Unless the temps are very hot, one fan should be OK.

Code 43 is the Starter Signal Circuit. The ECM is not getting a signal to the STA terminal when the engine is cranked. Check for shorts or open wire in the Black/White wire running from the starter, the start relay or ignition switch may have a problem.

Since the ignition switch also controls power to the fans, this may be a common issue.

http://oregonstate.edu/~tongt/camry

[Rogue10186]

Originally Posted by toyomoho

Check RDI and FL CDS Fan fuses. The system is designed to failsafe. If something fails or a wire breaks the fans should keep running. Find the service manual for this year/engine type at the link below and dig out the wiring diagram. The usually problem is the coolant temp sensor that controls the radiator fan but since both fans don’t work, not sure.

If you cannot solve the problem before driving home. Pull the power plug going to the radiator fan and apply 12V DC directly. The radiator fan has Blue (+) and White/Black (-) wires running to it. The A/C fan has White (+) and Red (-) wire running to it. Once power is applied, recheck the direction of the fan rotation to make sure it is pulling air in from the radiator. Unless the temps are very hot, one fan should be OK.

Code 43 is the Starter Signal Circuit. The ECM is not getting a signal to the STA terminal when the engine is cranked. Check for shorts or open wire in the Black/White wire running from the starter, the start relay or ignition switch may have a problem.

Since the ignition switch also controls power to the fans, this may be a common issue.

http://oregonstate.edu/~tongt/camry

Alright, I'll try that, but is the RDI and FL CDS fan fuses the same thing as the Fussible link labled Fan "30A" and the Cooling fan relay labeled "Fan No. 1"?

I really hope I can get this figurred out...


Edit!

I've found that the fans dont kick on at all when the engine is cold and I put the key in the "on" position with the engine off. Nor do they kick on for a short time when the engine is first started. I will check the relays and other things in the morning...

Thanks Again.

[toyomoho]

Both fuses are fusible links. The Fan No 1 relay controls the flow of power from the RDI Fan fuse to the radiator fan motor. The relay coil receives power from the Ignition fuse. The coolant temp switch and an A/C high-pressure switch control the relay. Make sure the A/C high-pressure and coolant switch have continuity.

Also check the 10A A/C fuse, which power the A/C fan.

[Rogue10186]

Ok, I checked all these:

Fan No.1 relay
Fan 30A fuse
Engine Main Relay
Engine coolant temp sensor
IGN 7.5A Fuse

I also rigged up the wires between the fan and battery, and both fans work, so it's obviously something inbetween the fans and the 'normal' power supply...
So what else is there that could be stopping the fans from turning on?
Also, if I just run power to the driver side fan, will this be enough to keep the car cool b/c isnt the passenger side fan just to take care of the A/C compressor?

[timebuilder]

I'll assume you used the link above to the “manuals” page, clicked on the first link, then found the Electrical Wiring Diagrams link on that page. Save that file when it downloads.

Read pdf page 155 (original page number is 158) and go over the description of how the radiator and AC sytems interact.

Scroll down to page 157 for the diagram. Check out the left hand side.

Here is an abbreviated approach:

With the key “on” and AC off, do you have battery voltage at the water temp switch? If yes, ground that wire. Does the fan come on? If yes, replace the water temp switch, because you said you have had the car up to temperature with no response from the fan.

No battery voltage at the temp switch wire? Let’s start back at the top.

You said you checked the fuses.


With the key on, AC off, the 7.5 amp ignition fuse should be sending power to the number 1 terminal of the “radiator fan relay No.1.” If you pull the relay out, you should be able to read battery voltage from the 7.5A fuse on terminal 1, and also see the same reading on terminal 4, which gets battery power from the 30A RDI fuse. Put the relay back in its socket.

Do you have battery voltage available at terminal 1 of the AC high pressure switch connector? If yes, use a jumper to apply a ground to terminal 1 of the AC high pressure switch connector, and you should hear the relay click and the fan come on.

You should have battery voltage on both of the switch wires with the connector installed on the switch. If not, then replace the switch. Now, bear in mind that the AC system wiring shown just to the right is supposed to operate the radiator fan on high speed if that AC high pressure switch is opened, and since this isn't happening for you, a run through these simple tests will tell you whether you have power where you should. Then, you begin looking at the power flow described on pdf page 155.

Keep it simple, and follow the power flow. You can have a discharged AC system, and your radiator fan will still run just fine. That's why I'm suggesting these basic tests.
If you had battery voltage at terminal 1 of the AC high pressure switch, the motor would be going on and off as the relay clicked when you applied the ground at the terminal. Since you already confirmed that the motor is good, a clicking relay without the motor running would mean the relay contacts are bad. Replace the relay.

This should be enough to get you started, not seeing the car and working from the diagram, alone. To continue, you will have to study the description of the system and check to make sure you can follow the stages of the circuit until you find where the voltage is lost.