Radiator Fan Issue -- HELP!
#1
01-31-2012, 10:43 PM
Join Date: Jan 2012
Location: Southern West Virginia
Posts: 1
Radiator Fan Issue -- HELP!
Hi all, I have a 1998 Camry LE that has a strange and inconvenient (to say the least!) issue. When I turn the engine off, the radiator fan runs and will not stop. The only way I can get it to stop is to turn the ignition key to the "on" position, but not start the car. This fan issue is causing my battery to go completely dead every time I stop the car for more than a minute or two.
I read elsewhere that this is an issue with a Fan Relay, so I tried to follow the steps given there. While the car was off and the fan was running, I removed and replaced relays until I found one that made the fan turn off when it was removed. This turned out to be the #2 fan relay. I replaced this part at the auto part store, but when I got home and turned the car off, the fan was running and the car is now dead again.
Where else should I look / what else can I do (besides take it to a mechanic)?
I read elsewhere that this is an issue with a Fan Relay, so I tried to follow the steps given there. While the car was off and the fan was running, I removed and replaced relays until I found one that made the fan turn off when it was removed. This turned out to be the #2 fan relay. I replaced this part at the auto part store, but when I got home and turned the car off, the fan was running and the car is now dead again.
Where else should I look / what else can I do (besides take it to a mechanic)?
#2
02-01-2012, 12:48 PM
If the fans continue to run with ign key off and turning ign key to ON stops the fans from operating, what happens when the ign key is again turned to OFF.
When the engine running do the fans run constantly, never turning off?
The fan control system is not simple! The statements below are generalized.
The system has 3 relays numbered 1, 2 and 3 plus 2 fans.
Relay 1 is the main relay; No 2 is used to set the fan speed (high or low). Relay 3 works when the AC system is on and AC compressor is actually running.
The fan system receives power from two sources. The ign switch and Engine Main Relay, both receive power from the battery.
When ign is ON, power runs through the ign switch to the ECU-IG fuse then to the fan relay solenoids. However these solenoids are not energized until the ground terminal of the relay solenoid is connected to ground.
What controls this grounding operation is a number of factors such as coolant temperature switches, AC pressure switch, AC magnetic clutch relay and even other fan relays. Thus with ign switch on the individual relay solenoids may have power available but their actual operation lies elsewhere as stated above.
The ign switch being turned to ON energizes the Engine Main Relay solenoid closing a switch allowing battery power to run from the battery to all the other fan relay solenoid switches (power bypasses the ign switch). When the relay switch is closed the motor is powered.
One motor is controlled by relay No 1 receiving power from the RDI fuse.
The other motor is controlled by relay No 2 receiving power from the CDS fuse.
Try a few tests.
With ign key off the ICU-IG fuse should not have DC power. If it does removing the ICU-IG fuse should disconnect power from the fan system relay solenoids.
Removing the Engine Main Relay should disconnect both relay solenoid and motor power. Remember the main relay receive power from two sources, one bypasses the ign switch.
If removing the ICU-IG has does not turn the fans off remove the Engine Main Relay If the fans turn off the relay switch could be sticking closed.
When the engine running do the fans run constantly, never turning off?
The fan control system is not simple! The statements below are generalized.
The system has 3 relays numbered 1, 2 and 3 plus 2 fans.
Relay 1 is the main relay; No 2 is used to set the fan speed (high or low). Relay 3 works when the AC system is on and AC compressor is actually running.
The fan system receives power from two sources. The ign switch and Engine Main Relay, both receive power from the battery.
When ign is ON, power runs through the ign switch to the ECU-IG fuse then to the fan relay solenoids. However these solenoids are not energized until the ground terminal of the relay solenoid is connected to ground.
What controls this grounding operation is a number of factors such as coolant temperature switches, AC pressure switch, AC magnetic clutch relay and even other fan relays. Thus with ign switch on the individual relay solenoids may have power available but their actual operation lies elsewhere as stated above.
The ign switch being turned to ON energizes the Engine Main Relay solenoid closing a switch allowing battery power to run from the battery to all the other fan relay solenoid switches (power bypasses the ign switch). When the relay switch is closed the motor is powered.
One motor is controlled by relay No 1 receiving power from the RDI fuse.
The other motor is controlled by relay No 2 receiving power from the CDS fuse.
Try a few tests.
With ign key off the ICU-IG fuse should not have DC power. If it does removing the ICU-IG fuse should disconnect power from the fan system relay solenoids.
Removing the Engine Main Relay should disconnect both relay solenoid and motor power. Remember the main relay receive power from two sources, one bypasses the ign switch.
If removing the ICU-IG has does not turn the fans off remove the Engine Main Relay If the fans turn off the relay switch could be sticking closed.
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