kevinthegreat Posted August 14, 2011 Report Share Posted August 14, 2011 i guess im just dumb, but i cant figure out how to hook up the relays to my efan harness. i have 05 efans and they are hooking up to three relays. i need to know where to hook up the green and blue wires that come from the pcm. i know where they go in the pcm, but im not sure where to hook them up at on the relays. if someone can post a pic of how their relays are ran, that would be awesome since i cant figure out a f-ing diagram. thanks for any help you guys can give me Quote Link to comment Share on other sites More sharing options...
paulguy Posted August 14, 2011 Report Share Posted August 14, 2011 Factory harness or aftermarket? found this diagram http://i2.photobucket.com/albums/y28/SnakeOiler/Vehicles/Silverado/Projects/ElectricFans-Take2/05FanWiring.jpg The pcm wires just sen a negitve reference wire to the coil on the relays(85 or 86), the other side of the coil should be hot Quote Link to comment Share on other sites More sharing options...
kevinthegreat Posted August 14, 2011 Author Report Share Posted August 14, 2011 theyre factory fans with an aftermarket harness. i want to say that its a nelson harness thats been modified. im not really sure because i got it used. theyre are three relays, which relays do i hook the pcm wires to? ill see if i can post some pictures of it later today if i can. Quote Link to comment Share on other sites More sharing options...
kevinthegreat Posted August 14, 2011 Author Report Share Posted August 14, 2011 this is what im working with. everything is hooked up except the pcm wires and one jumper. can someone tell where they go? Quote Link to comment Share on other sites More sharing options...
paulguy Posted August 17, 2011 Report Share Posted August 17, 2011 (edited) Well that pic isn't great and it's hard to tell what wires go to what pins on the relays. But like i said the coil that needs to be powered is pins 85 and 86. Hot on one side(battery power) and the negative trip(pcm) on the other. In the parallel/series two speed fan harness diagrams that I've looked at 2 relays are used for high and one relay for low. If everything is fused properly, you can use a grounding test light to trip the relays to test, and then without the pcm wires hooked up, you won't risk damaging anything. Edited August 17, 2011 by paulguy (see edit history) Quote Link to comment Share on other sites More sharing options...
misterp Posted August 17, 2011 Report Share Posted August 17, 2011 (edited) The posted schematic will work, it's how GM wires their fans. You just need to know how to read the diagram. Try this, maybe it will clear things up for you - but all the info you need is already on the original diagram. Mr. P. - MORE: First connect the relays, do not connect to the PCM yet; with the truck OFF, take the green wire to the PCM and touch it to the negative battery post, the fans should come on low speed, then touch BOTH the green and blue wires to the negative battery post, and the fans should be on high-speed. Once you have passed that "bench test" then go ahead and connect the green & blue wires to the PCM. MAKE SURE both fans are spinning in the same and correct direction. Mr. P. Edited August 27, 2011 by Mr. P. (see edit history) Quote Link to comment Share on other sites More sharing options...
kevinthegreat Posted August 18, 2011 Author Report Share Posted August 18, 2011 I have it figured out now. Thank you both for helping me out Quote Link to comment Share on other sites More sharing options...
rocksss Posted August 19, 2011 Report Share Posted August 19, 2011 I GOT A ORIGINAL WIRING HARDNESS OUT A 06 COMPLETE FOR 75 BUCKS IF INTERESTED PM ME THANKS Quote Link to comment Share on other sites More sharing options...
T-Bag Posted August 19, 2011 Report Share Posted August 19, 2011 I GOT A ORIGINAL WIRING HARDNESS Quote Link to comment Share on other sites More sharing options...
kevinthegreat Posted August 27, 2011 Author Report Share Posted August 27, 2011 im having problems. im doing this bench test that mr.p posted but both fans will only come on in low range. only the passenger side fan comes on high with both wires touched to the negative side. i have the wires ran the way they are in the above diagram. battery is charged and relays are good. is there something wrong or are they working correctly? please help, these fans are holding me back from getting the truck running Quote Link to comment Share on other sites More sharing options...
kevinthegreat Posted August 27, 2011 Author Report Share Posted August 27, 2011 im having problems. im doing this bench test that mr.p posted but both fans will only come on in low range. only the passenger side fan comes on high with both wires touched to the negative side. i have the wires ran the way they are in the above diagram. battery is charged and relays are good. is there something wrong or are they working correctly? please help, these fans are holding me back from getting the truck running Quote Link to comment Share on other sites More sharing options...
kevinthegreat Posted August 27, 2011 Author Report Share Posted August 27, 2011 im having problems. im doing this bench test that mr.p posted but both fans will only come on in low range. only the passenger side fan comes on high with both wires touched to the negative side. i have the wires ran the way they are in the above diagram. battery is charged and relays are good. is there something wrong or are they working correctly? please help, these fans are holding me back from getting the truck running Quote Link to comment Share on other sites More sharing options...
paulguy Posted August 27, 2011 Report Share Posted August 27, 2011 Are all three relays ground in high? Quote Link to comment Share on other sites More sharing options...
kevinthegreat Posted August 27, 2011 Author Report Share Posted August 27, 2011 im not sure how to tell. when i touch the low side trigger wire to ground only the passenger side fan comes on and its on high. when i touch the high side trigger wire both fans come on on low. Quote Link to comment Share on other sites More sharing options...
kevinthegreat Posted August 27, 2011 Author Report Share Posted August 27, 2011 disregard that last post. when i touch the low side trigger wire (green) the drivers side fan comes on at high speed. when i touch both wires only the passengerside fan comes on and its on high Quote Link to comment Share on other sites More sharing options...
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