Radiator Fan problems..
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Junior Member
Joined: Dec 2021
Posts: 1
From: Austin-ish
Radiator Fan problems..
A couple days ago my wife's 2011 xB started overheating with the A/C on; turn the A/C off and it cools back down.
A/C works fine, but only one fan (right/passenger side) seems to be working at any time, whether the AC is on or not.
I let it run up to about 225 with the A/C on, then turned the A/C of and it cooled back down to 200.
I didn't have time to work on it, but since the weather is nice I told her just don't run the A/C until the weekend when I can troubleshoot it... since one fan works, I can switch around relays, fan plugs, etc. to see what going on...
Today she texts me and says that the Temp light came on again while she was sitting in the car wash line. She brought it home and this time neither fan is working.
The terminals for the relays are hot, but I can't access the fan connectors without pulling the battery; she has to get state inspection this week (OBDII), so if I disconnect the batt, the ECU will reset, and she won't be able to get inspected.
Given the behavior though, I'm not betting on both fans being bad. The "RDI" and "CDS" fuses appear to be fine.
Any ideas on what is going on? Can the Temp Sensor cause only one fan to run, then progress to no fans? Also, where is the fan control module on these cars?
___
A/C works fine, but only one fan (right/passenger side) seems to be working at any time, whether the AC is on or not.
I let it run up to about 225 with the A/C on, then turned the A/C of and it cooled back down to 200.
I didn't have time to work on it, but since the weather is nice I told her just don't run the A/C until the weekend when I can troubleshoot it... since one fan works, I can switch around relays, fan plugs, etc. to see what going on...
Today she texts me and says that the Temp light came on again while she was sitting in the car wash line. She brought it home and this time neither fan is working.
The terminals for the relays are hot, but I can't access the fan connectors without pulling the battery; she has to get state inspection this week (OBDII), so if I disconnect the batt, the ECU will reset, and she won't be able to get inspected.
Given the behavior though, I'm not betting on both fans being bad. The "RDI" and "CDS" fuses appear to be fine.
Any ideas on what is going on? Can the Temp Sensor cause only one fan to run, then progress to no fans? Also, where is the fan control module on these cars?
___
Last edited by MR_LUV; Dec 9, 2021 at 05:29 AM.
Senior Member
SL Member
Joined: Mar 2009
Posts: 801
From: Mesa, AZ USA
Sometimes the fans can seize up. You can check for this by turning the blades by hand (ignition off) They should spin freely.
A seized fan produces no "back emf" to reduce the current flow, so wiring can get hot.
If you disconnect the battery, you have to drive about 100 miles (on a Corolla) before the computer has relearned whatever it has to learn. Found that out the hard way,
but the emissions people were nice about it. Might even give you a time extension to get the mileage in. Just take it in before the deadline.
__________________
A seized fan produces no "back emf" to reduce the current flow, so wiring can get hot.
If you disconnect the battery, you have to drive about 100 miles (on a Corolla) before the computer has relearned whatever it has to learn. Found that out the hard way,
but the emissions people were nice about it. Might even give you a time extension to get the mileage in. Just take it in before the deadline.
__________________
Last edited by MR_LUV; Dec 9, 2021 at 08:04 PM. Reason: Awarded 10 Yr Badge
You're fine to pull the battery. The ECU resets in about 5-20 miles of driving, if that. I've pulled my battery right before having to get mine smogged and it shows ready to go on my scanner quite quickly.
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