Problem With Cooling Fans, please have a look:

[Dr Tweak]

I tested out the cooling system today on this '98 Corolla with a 2ZZGE swap and the fans aren't working right. My first problem was the the relay was normally closed and I needed a normally open one. This is now taken care of, but for some reason, as soon as I turn the car on, the computer turns the fan on.

Why would the computer do that?

I'm using the temp sensor from the 1ZZFE because it has an extra wire to run the '98's temp guage, could that be the problem... maybe the signal isn't right? Does the computer turn the cooling fan on when it's in limp mode? I am not getting a CEL...

Any suggestions?

[dexter_5000]

not sure but the wire could be broken somwhere. my teacher told us that toyota set them up if the circuit was open that it would turn the fan on so it wouldn't risk overheating the engine.

[Dr Tweak]

Hmmm with the original setup it was like that which is why they used a normally closed relay, but now it's normally open and I tested the circut out right to the ECU. For some reason the ECU is grounding that wire, no doubt about it. I just can't figure out why.

I have figured at the the pressure switch on the Corolla is also backwards from the Matrix, so tomorrow I'm going to install the Matrix one, and we'll see what effect that has. I don't really see why that would cause the ECU to turn the fan on, but I'm glad it made me look at it because otherwise the a/c wouldn't have worked right.