P0480 - P0481 / With Manual Fan Switch?
07-03-2009, 07:28 PM
#1
P0480 - P0481 / With Manual Fan Switch? I have installed a manual switch for my fans - when I use the switch I get P0480/1 DTCs. I am assuming this is because I am overriding the PCM to turn the fans on and its knows it? Is there a way to fix this?
07-03-2009, 08:51 PM
#2
I forgot the resistors hehe 
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06-04-2011, 07:58 AM
#8
I realize this is an old thread, but I wanted to throw my two cents worth in here for future users.
I wired my fans using a DPDT switch, but I used two relays with it. One for low speed and one for high. If you follow this (and other posted diagrams that don't use relays) you can leave the fan on with the key off. Not an option for me as I would certainly be the one to leave it on and run the battery down. If I was using this strictly at the race track between rounds, I might go this way. But I want it to control the fans for other reasons. Therefore, by using relays, I was able to use a 12V power source that is hot in run only.
I tried every combination of diodes I could come up with to prevent the ECM from finding a fault in the circuit and setting a code. I couldn't come up with it. The ECM checks for low and high voltages at certain times and the diodes would not solve that.
This diagram showed the use of resistors to stop the codes. I have no idea why, but they work flawlessly. I'm pretty good with electrical problems, and I can't get my arms around this one, but it works.
Finally, one of the neat features of this (and the other popular diagram out there) is the ability to see when the ECM has the fans on and at what speed. However, with the use of the diodes where they are in this diagram, I believe you would lose that and they would only come on when you commanded them with the switch.
I wired my fans using a DPDT switch, but I used two relays with it. One for low speed and one for high. If you follow this (and other posted diagrams that don't use relays) you can leave the fan on with the key off. Not an option for me as I would certainly be the one to leave it on and run the battery down. If I was using this strictly at the race track between rounds, I might go this way. But I want it to control the fans for other reasons. Therefore, by using relays, I was able to use a 12V power source that is hot in run only.
I tried every combination of diodes I could come up with to prevent the ECM from finding a fault in the circuit and setting a code. I couldn't come up with it. The ECM checks for low and high voltages at certain times and the diodes would not solve that.
This diagram showed the use of resistors to stop the codes. I have no idea why, but they work flawlessly. I'm pretty good with electrical problems, and I can't get my arms around this one, but it works.
Finally, one of the neat features of this (and the other popular diagram out there) is the ability to see when the ECM has the fans on and at what speed. However, with the use of the diodes where they are in this diagram, I believe you would lose that and they would only come on when you commanded them with the switch.
