07 Yukon xl 2500 E fan upgrade... Relays already there?

[timmy1909]

I was just thinking of doing a stock electric fan upgrade and was looking around for info... I see alot on the older body style trucks, but nothing about the 07 and up...

 

So I was looking at my relay/fuse panel under the hood and saw that the fan high and low relays are in place as well with the main relay... the 40 amp fuses are there as well. Would the fan wires be tucked away somewhere seeing that everything else is in place... Would the ECm already be programed for them as well? I am getting tired of the clutch fan being worthless at Idle... 

 

07 GMC Yukon XL 2500 

[dna9656]

At 1st I thought you were talking about the fan for your A/C, heater and defroster but you're not.

You're talking about the engine fan. Don't assume others know what you're talking about because you do know.

When you write you need to provide all the info you can so those of us not inside your head can know what you're taking about.

For me if the fan comes on and off in accordance with the engine's needs that's fine, it ain't broke and it it ain't broke I don't fix it.

If it's not and your engine is over heating you got a problem. It's usually a tired temp sensor or it got disconnected some how, or other wiring problem.

I have seen guys run  bigger radiators thinking a cooler engine runs better; if cooler is about 200F that's fine but if you take the t stat out and put a

bigger radiator or a fan that runs all the time you may not get up to operating temp and that's no good either.

The engineers usually got the engine cooling down to what's needed plus a little to allow for blockages.

If you're not overheating I'd leave well enough alone.

[timmy1909]

7 hours ago, dna9656 said:

At 1st I thought you were talking about the fan for your A/C, heater and defroster but you're not.

You're talking about the engine fan. Don't assume others know what you're talking about because you do know.

When you write you need to provide all the info you can so those of us not inside your head can know what you're taking about.

For me if the fan comes on and off in accordance with the engine's needs that's fine, it ain't broke and it it ain't broke I don't fix it.

If it's not and your engine is over heating you got a problem. It's usually a tired temp sensor or it got disconnected some how, or other wiring problem.

I have seen guys run  bigger radiators thinking a cooler engine runs better; if cooler is about 200F that's fine but if you take the t stat out and put a

bigger radiator or a fan that runs all the time you may not get up to operating temp and that's no good either.

The engineers usually got the engine cooling down to what's needed plus a little to allow for blockages.

If you're not overheating I'd leave well enough alone.

Im Running the stock clutch fan... I have changed the fan clutch and a new thermostat... Flushed the radiator and cleaned the AC fins and the radiator fins to make sure I have good air flow

through them. If this was a post about overheating, then I would have asked... but its not, and I didnt... Truck is a Yukon xl 2500 6.0 with 4:10 gears (stock)

 

When I idle the truck with the AC on the temps start to get hot (240+ monitored by the torque pro app) then the AC starts to get warmer... this would be an AIRFLOW ISSUE hence why I would like to go with E-Fans!!!

If I idle up the truck the temps will come down... Again AIRFLOW ISSUE! 

I have 2 aftermarket trans coolers that have fans installed, 1 is a puller and the other is a pusher. This is my 2nd NBS 2500 truck and they both had the same issue. 

I use it to pull my 6k work trailer around and when the AC is on I have this issue. without the AC on the truck seems fine. (yes I have had the AC system checked, vacuumed out and refiled to 

spec) 

 

I guess I will have to figure out the fan wiring on my own. I have found some info already that will get me started. but I did find out that I will need to have the fans activated by HP tuners 

or EFI Live... The truck is almost prewired for it (the relays and fuses are there) I just need to add 6 more wires to finish it. (Fan power, Ground and ECU triggers) Then it will work like stock

with high and low functionality. This is what I have come up with so far:

 

1- Ground Input Signal from ECM for Low Speed Cooling Fan Relay Control ?
* (Factory uses Dark Green colored wire).
* Connect to (Under hood X2 Connector Pin A1).


2- Ground Input Signal from ECM for High Speed Cooling Fan Relay Control ?
* (Factory uses Dark Blue with White Stripe colored wire).
* Connect to (Under hood X2 Connector Pin B5).



3- Output to Cooling Fan Motor Supply Voltage ?
* (Factory uses Gray colored wire).
* Connect to (Under hood X1 Connector Pin C1).

4- Output to Cooling Fan Motor Supply Voltage ?
* (Factory uses Yellow colored wire).
* Connect to (Under hood X1 Connector Pin C2).

5- Output to Cooling Fan Motor Supply Voltage ?
* (Factory uses Light Blue colored wire).
* Connect to (Under hood X1 Connector Pin D1).

6- Ground ?
* (Factory uses Black colored wire).
* Connect to (Under hood X1 Connector Pin D2).

 

Anyway... thanks for your input on the basics of a cooling system but, If you have nothing to add to the OP then please do not chime in. 

[swathdiver]

GM runs a clutch fan because it pulls more air through the radiator than even my K5L 700 watt fans.  I reckon that your two transmission coolers and their fans are blocking the air flow or your clutch fan is not working properly.

 

Are the baffles around and below the radiator still in place?  If they fall away air will pass around and not through the radiator.

[timmy1909]

Trans coolers are located under the radiator, so they are not inline with the airflow, one is a derale and the other is just a bar and plate cooler I had from a supra project I didn't use...

There is no way the clutch fan pulls more at idle then the stock 2 speed E-fans... NO Way! Clutch fan is new and it is an HD one, I even changed the fan blades. Yes baffles are there and the radiator is new. I am sick of changing parts as I have an entirely new cooling system and the problem still persists. 

 

I have just about finished the wiring for the e-fans so they will work and appear like stock with the factory supplied fuses and relays. So this thread can be closed...

 

 

[richard wysong]

don,t get mad, swathdiver was just pointing out things that you may have overlooked and that because of the pitch of the blades the clutch fan WILL draw more air thru the rad than the e fans, hope the efans work out for you

[swathdiver]

5 hours ago, timmy1909 said:

There is no way the clutch fan pulls more at idle then the stock 2 speed E-fans... NO Way!

 

Well, that's what one of the engineers who designed the 900s told us.

 

There are two main sets of electric fans, 500 watt motors and 700 watt motors.  The 500s used a pair of 5-blade rimless blades or 5 and 7 rimmed.  The 700s used 9 and 7 blade rimmed or a pair of 5-blade rimmed.

 

Let us know what you used and how it goes when done if you will.

[timmy1909]

I have the 9 blade dual e-fans on my other truck (03 Suburban 2500) and they far out perform the clutch fan. The Fans I use are the GT fans, the LS1's are smaller. 

 

with the e-fan truck I can sit at Idle with the AC on and its still Ice cold and the temps do not rise hardly at all like the stock clutch fan. I would be over 230 sometimes reaching 240 and the AC turns to a swamp with the clutch fan truck... Let the engineer drive each on of my trucks on a hot day and see which one he prefers... The one with the E-fans is far superior... and it did not come that way. I installed them 2 years ago with a kit that I found online... and found the fans in a junk yard for $20. The fans run at 2 speeds... and with the relays that are in my 07 that came stock with the truck it will act the same. I just have to pin and add the wires to the stock fuse/ relay panel.