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The tune is changed so that its Fan #2 control instead of Rec Door Signal. Have no idea what Pin 17 does. Unless its from the HVAC controls to request AC.
If you remove the plastic cover over the fuse block, you will see two Studs. They are fused. pick one.
Here are two schematics that I created: 2-relay and 3-relay.
the way i see it, in the 3 relay neither fan is going to come on until the ac circuit is switch, the ground for fan one runs to the power of fan 2... idk
ok so who can help me with this then i did the i changed from the 3-pin relay to the 2-pin relay and now my a/c clutch compressor starts running as soon as the truck starts and the fan along with it. is there something different between the two that would cause it.
I grounded it to the battery and started it and it did the same, but when i took the ground off the battery while it was running it shut the fan off and the clutch compressor kept running.
Bringing this back from the dead with a quick question.
I have wired up my fans on a 2000 silverado according to a different diagram that looks just like the 3 relay diagram above with the exception of one thing. I have the A/C trigger wire tapped into the dark green wire (circuit 59, circled in red below). my passenger side fan is on constantly even with the key off ( have to disconnect the fan or battery to shut it off). I am pretty sure this is my problem.
I stumbled upon this thread and it says to tap into the green/white wire (circuit 459, circled in blue below). Looking at my harness it runs from the under hood fuse box down to the PCM. Is that the correct wire to tap into?
To answer your question directly, the fan itself is power activated, while the relay control is ground activated. The fan is always grounded even when off, thats why it activates your relay at all times.
So if I am reading your link correctly you wired up your fans according to your picture posted in the first post. Correct?
I didn't was not planning to switch to an 02 OS and wasn't planning on using an overide switch, but from reading that link it looks like if I don't I will only have low speed with the ECM and high only when a/c is on.
I am still confused on if I should be in the green/white wire. If I am thinking correctly it shouldn't make a difference.
If all else fails I will pull the harness back apart and wire it up as you had it along with the OS swap as it's not a huge deal.
05-06-2013, 05:59 PM
