Electric fan wiring question

[88lance]

Hello everyone, got a 2002 Z71 Tahoe, clutch fan. Found an electric fan and fuse block in the junk yard, and had them take it out for me.

They split the harness between the fuse block and the fans, but most of the wiring looks pretty straight forward, colors just go back together it looks like.

The little plug with the two wires (light blue and green) coming off the fuse block are there, as is the big red power wire.

Here's what I'm confused on.

-where is the ground wire?? I have 4 wires leaving the fans and 4 color matching wires leaving the fuse block heading for the fans that seem to obviously just go together, but no ground...

Is the ground just supposed to be spliced in the two fan grounds or something?

-secondly, what are these 3 miniature blue wires that come from the fuse block in the photo? I don't really know what these do or if I need them.

Thanks!

 

[nonickatall]

I guess you have one ground for both and two plus lines for each of the fans.

Just measure the passage. The positive cable must have continuity to ground, but the positive cable don't have continuity to the other positive cable.

 

[88lance]

I guess you have one ground for both and two plus lines for each of the fans.

Just measure the passage. The positive cable must have continuity to ground, but the positive cable don't have continuity to the other positive cable.

That's what I was thinking, one of those wires on each fan is a ground, so tap into each ground and ground it to the frame,l as it continues it's way to the fuse block, if I am seeing this correctly.

 

[Fless]

Here's what the harness should look like all put together.

 

[88lance]

Found out the wiring for the ground, so apparently only the fan with the black wire goes to the frame for ground, just like in the photo from Fless. The other 3 fan wires go straight towards the fuse block, but the black heads to the frame to ground before carrying on to the fuse block.

 

[88lance]

So AC turns on passenger fan to high, like it's supposed to.
Operating temp without ac is both fans on low, which works.

But AC with operating temp combined is supposed to be both fans high.

Instead, when it gets to that point, it turns the drivers fan off, and turns the passenger fan on high.
It's like there is no setting for both fans on high. If the passenger kicks to high because of the AC, the driver fan just completely stops.

Any ideas?
Thanks

 

[88lance]

So AC turns on passenger fan to high, like it's supposed to.
Operating temp without ac is both fans on low, which works.

But AC with operating temp combined is supposed to be both fans high.

Instead, when it gets to that point, it turns the drivers fan off, and turns the passenger fan on high.
It's like there is no setting for both fans on high. If the passenger kicks to high because of the AC, the driver fan just completely stops.

Any ideas?
Thanks

Figured it out, turns out both blue wires from the fuse block are supposed to tie together. Problem solved, everything works great

 

[02slpSS]

Figured it out, turns out both blue wires from the fuse block are supposed to tie together. Problem solved, everything works great

so where do the 2 grounds connect to? I have one also, but I don't have to 2 ground eyelids, and I don't know where they connect to.

 

[mattbta]

so where do the 2 grounds connect to? I have one also, but I don't have to 2 ground eyelids, and I don't know where they connect to.

There aren't two grounds. Only a single eyelet as @Fless earlier post shows: 4

The OEM grounding is in the right side frame/bumper area. There's a bung for a bolt there even on earlier models.

 

[02slpSS]

So I’m a little confused if there not grounds what do they connect to? And this is where I’m starting from I don’t even have the eyelet on my harness

 

[Fless]

There are two ground WIRES that are attached to ONE eyelet. Maybe the diagram at this site would help (if the PU trucks are the same), but I don't know in what year your harness was born:

https://www.silveradosierra.com/media/2005-electric-fan-wiring-diagram.379832/

 

[02slpSS]

There are two ground WIRES that are attached to ONE eyelet. Maybe the diagram at this site would help (if the PU trucks are the same), but I don't know in what year your harness was born:

https://www.silveradosierra.com/media/2005-electric-fan-wiring-diagram.379832/

I appreciate your help my harness is from a 2005 Tahoe, I screenshotted the diagram and I circled where I don’t understand, what is the 1 wire and is 2 the double ground that is attached to the eyelet

 

[rockola1971]

I appreciate your help my harness is from a 2005 Tahoe, I screenshotted the diagram and I circled where I don’t understand, what is the 1 wire and is 2 the double ground that is attached to the eyelet

Your circled #1 is the power feed for Relay #3 which is half of the control for high speed fan relay control (Both fans on). Relay #2 is the other half of high speed control. Your circled #2 is indeed the double ground at the eyelet. This 2 wire ground is switched at Fan relay #3 and allows that double eyelet to provide the left fan a ground during low speed mode. Honestly the engineers overthought this setup and it is a dumb way to do it.

 

[02slpSS]

Your circled #1 is the power feed for Relay #3 which is half of the control for high speed fan relay control (Both fans on). Relay #2 is the other half of high speed control. Your circled #2 is indeed the double ground at the eyelet. This 2 wire ground is switched at Fan relay #3 and allows that double eyelet to provide the left fan a ground during low speed mode. Honestly the engineers overthought this setup and it is a dumb way to do it.

so, what I missing to run the double eyelet ground because from what I am looking at that is the only thing I'm missing, it looks as if they run into the black fan wire?

 

[rockola1971]

so, what I missing to run the double eyelet ground because from what I am looking at that is the only thing I'm missing, it looks as if they run into the black fan wire?

The 2 black wires in your pic that go toward the top of the pic dont have a ring terminal (eyelet) on them?

Your previous electrical diagram shows one of the ground wires coming off of fan relay #3 and the other black wire comes from the Right fan. The end of those 2 wires would then terminate into a ring terminal. So what is attached to your right fan now? Wires been cut?

 

[Fless]

^^^ THIS. I see only one black wire in the pic; what looks like another one is just a shadow. Extend the black wire from the right fan so it can be grounded with the black coming from the relay.

Find the black wire from the right fan, it should be somewhere in the harness, it looks like it may have been clipped inside.

 

[rockola1971]

^^^ THIS. I see only one black wire in the pic; what looks like another one is just a shadow. Extend the black wire from the right fan so it can be grounded with the black coming from the relay.
Find the black wire from the right fan, it should be somewhere in the harness, it looks like it may have been clipped inside.

I dont think the one black wire near the other is a shadow. The 2 are not bent the same in numerous places. Im curious if only one goes to the relay block in the pic and the other is cut and just laying there near the block. Cant tell in the pic.

 

[Fless]

I dont think the one black wire near the other is a shadow. The 2 are not bent the same in numerous places. Im curious if only one goes to the relay block in the pic and the other is cut and just laying there near the block. Cant tell in the pic.

You're right, it's hard to tell; I looked at that way too long. But if the diagram is correct there shouldn't be a second black wire coming from the relay block.

 

[02slpSS]

Sorry for the picture here is a clearer picture of what I have, the wires were previously cut by my brother he gave this to me 

 

[rockola1971]

Sorry for the picture here is a clearer picture of what I have, the wires were previously cut by my brother he gave this to me 

In your post #14 pic I can clearly see 2 black wires that appear going toward the top of the pic. They are located directly left of the wiring plug in the pic. Yet in your newest pic posted it does not show 2 black wires?????