No problem.

There not cheap but they are a nice piece. They are also on sale right now for $20 off.


I would buy 1 now while its on sale and sell your other harness to recoup some money.

I am not sure why, but they are telling with HPT you don't need an OS swap. I read mine out with HPT after flashing with EFI live and all the settings were correct so I am not sure what the difference would be.

 

I am new to the Board and saw this thread so thought I would post my questions here.


I have a 03 Sierra 1500 4.8 and I am looking to change to the E fan set up. So from what I understand I am going to have to have my pcm flashed so it will all work properly with the a/c?


So is this something that can be done using a Tech II or does it have to be some software that I will have to pay to have someone flash it for me?


If a tech II will work is there anyone that might could help me thru the process?

 

Not with the A/C, but you have to enable the Fan control in the PCM, which will control turning the fans on when the ECT hits a certain temp. Since your truck doesn't have e-fans, it's not enabled. Anyone with HPTuners or EFILive can flash it for you, not sure about Tech II but I'd assume it's possible.

 

Also new to the board and Google got me here because of a similar problem. I've got an 05 setup that I pulled from a junkyard for $50. Got the harness cleaned up and wired up. I was using Hptuners to enable the fans and after laying in the tune I have the same problem. Fans are on as soon as I turn the key on. I have a 99 Silverado with a 6.0 LQ4. I can control the fans individually turn on Fan1 and the low speed fans are on turn on Fan2 and the high speeds work. I can even shut the fans off at KOEO but as soon as I back out they are on.

Is copying over a stock 02 OS the answer?
Does anyone have a stock OS for and 02 LQ4?

Thanks,
Walt

 

That should take care of it. Thats what mine was doing.

 

Ok another noob question and this is about tuning. I'm using HPtuners. If I have a stock tune inhand that is similar do I just change the VIN of that donor tune and write the full thing in and then change my parameters from previous? Sorry but this changing the OS is confusing and with HPtuners credit based system I'm not sure if I'll need to spring for more credits to change over the 02 tune to mine.

Also since the 99-02 Silverado A/C are controlled via pressure switches rather than pressure sensors how and when do the secondary fans come on? Does the 02 OS have allowances for this?

Thanks,
Walt

 

I have never used hp tuners but on efi live i just took a stock 2002 os and changed the vin and everything else that was different in my tune and did a full flash.

As for the a/c you will need to get a harness that will allow u to tap into the a/c harness. There was a link for a nice one earlier in the post. Hope this helps

 

Here is the link.---> 1999-2002 Full Size Truck Dual Fan Conversion Kit

 

DO NOT buy the harness with the a/c tap. It's a terrible way of doing the efans.

Get the "2 pin" harness, this simulates the OEM setup and runs the fans as closely as intended.

 

Here is a 2002 6.0L file in HPT format