both radiator fans run while the key is off

[alollich]

Hello,

I did not find anything in the search function related to my problem. When you turn the car off both radiator fans come on regardless of outside temp or engine temp and will not shut off until the battery is dead. While the engine is running the fans will cycle like normal and will maintain the correct engine temp. I checked the relays with a OHM meter and both relays appear to be functioning and will click when 12 volts is applied. I checked the socket they plug into in the fuse block and when the key is off there is about 7-8 volts present in one of the pins. Whe the key is on and the engine cold there is not any current in that same pin. My fear is a short somewhere. Does anyone have a suggestion on something else that would cause the fans to run with the key off?? I am not aware of any kind of seperate fan controller on this car. I think it is in the temp sensor, relays, or wiring. No check engine light or other electrical problems exist.

Thanks

[Bernie3]

Welcome to the Forum.

1. What year and model is your car? You should add this to your profile.
2. Which relay socket(s) have the 7-8V when Ignition is off, and at what pins.
3. Check the relay contacts themselves with an ohm meter to make sure none are shoted or open. Clicking alone is not proof of proper operation.

[alollich]

The car is a 1999 Corolla. I did check the relays with the ohm meter and they appear to be fine. I am no master when it comes to relays and switches but when I apply 12 volts to the relay, pins 87 and 30, and then check the connection between 85 and 86 on the relay I have continuity. For example the large green relay for the main radiator cooling fan the pin/socket in the fuse block that has voltage in the off position is the 87 pin on the relay. This time when I checked it is has a full 12 volts in the key off position not 7-8 like before. I would not expect there to be 12volts at this part of the fuse block in the key off position.

Does it make any sense that both relays woud go bad at the same time? By both relays I mean the large green square one that runs the main cooling fan and the second redish brown smaller one that runs the a/c fan. the only way both fans stop running in the key off position is to remove both of these relays.

[Bernie3]

The relay designations you have don't relate to the Haynes wiring diagram I have.

Check that there is no electrical connection between the Common (C) and Normally Open (NO) terminals of the Engine Main Relay when the relay is off.