Enabling Fans for 99-07Classic Silverado or Sierra Trucks or any P01/P59 PCM with Universal Patcher 

Yes thank you. It was done in March of last year and that is allergy season around this area. It gets so bad sometimes you can see a yellow dusting on vehicles from all the pollen.

There are way other ways to view. If you choose the a/b or a[b] at the top of each table it will show them side by side. There is a way to just select those tables needed and add them to a patch file then it’s one click and it will copy all of them over to yours.

It’s allergy season here. Everything is blooming and pollen is in the air. I’m sure all the delays aren’t that important. I first started off with just changing the basic on and off temps and pressures and it seemed to work fine. I just went ahead and looked deeper into it with Universal Patcher because I could compare bins from different years and was like let me just copy everything over.

@@brandongarnold Here in MI we still have snow on the ground in spots lol. Feels like its forever before we get spring weather. Do you use the red/blue pcms mostly or the red/green 1 meg file size ones? I'm guessing the 512k file size red/blue for you. What OS number do you prefer? Maybe os doesnt really matter now that the xdf files aren't needed. It's bizarre to me the xdf file isn't needed since thats what took all the hex and made it into something we could understand from how I understand it.

oops meant blue/green not red/green. Have you messed the blue/green style? I googled it and it seems like the same bench harness for the red/blue will work for it.

I actually grew up in Northern MI. Left after graduating in 2002 and moved to Tennessee then to Arkansas and now back in Tennessee. I mostly mess with the blue/green on my own stuff with the 7603 OS. On my 2005 2500hd I have swapped over to the 7603 and applied a lean cruise patch that’s posted up on pcmhacking.net and have been playing with it. I was able to increase fuel economy by and extra 1.5-2mpg by leaning out to around 16:1afr at steady speeds above 45mph. I am contemplating converting from drive by wire to drive by cable on the same truck just to see what it takes. From what I’m seeing one of the more common issue in the 03-07 classic trucks with age is throttle issues. I’ve flashed a few red/blue for friends but that’s pretty much it. I don’t do any of it for anything more than fun.

@@brandongarnold Ah ok so you have the 1 meg file size pcm which I read is better for mods. So you didn't actually ls swap, you already had the lq4 I'm guessing in your truck, nice! I did do dbw in my truck, hope it doesnt fail too soon. I do actually have a dbc intake and harness from the first lm7 I bought. The motor was in rough shape so I sold it to recoupe some of the money I spent on the setup. It worked out good overall since I have a spare set of 862 heads, pcm and full harness, and that intake from it still. So flashing blue/green and blue/red you can use your same bench harness right? I've got a couple of folks asking me to remove vats for them but I've only done blue/red but it sounds like its all the same. My os is the 2156 one. Nice to live in Tennessee I'm sure, beats this cold weather up here. Can't imagine living in the UP. Now that I know universal patcher doesnt need the xdf files I'm assuming removing vats from any gen 3 pcm should work, right? I'm on the same page as you, I want to tune for best fuel economy though I think my truck should do outstanding. With the 4l60e and a 2:73 rear gear, it turns under 1900 at 80 mph but I don't go faster then 75 so its even lower and feels good. It doesnt down shift climbing these tiny hills we have here. I don't have the speedo working yet, minus using a gps so I haven't checked to see what I'm actually getting.

Are you having an issue with fans coming on for air conditioning? Or are you just taking about when the engine reaches the temperature set point?

I probably didn’t mention it in the video because that was a 2004 I was working on with but on the 99-02 you need to find the Auto_Recirculation_Option table and uncheck the box for it. Factory settings use pin 33 to control the recirculate door. Unchecking it changes settings over to fan control from that pin. That would be high speed fan though not low speed. You would then have to replace the a/c high pressure 2 wire switch with a 3 wire high pressure sensor and wire it to the pcm pin 45 in connector 1 and the pins 14 and 80 in connector 2 to get the fans working fully functional with the A/C.

@@brandongarnoldThanks for the reply. I can't get fan #1 or fan #2 to come on. As of right now I don't have ac working. but the truck has ac. Is the ac possibly my problem?

@@brandongarnoldAfter checking again I do see my AC (auto reciliation option) is checked on 1PCM but not the other. So that would explain fan #2 not working but still why no fan #1

Those seem to be the stock settings across the board for all LS engines. Honestly my stock truck came factory with a fan clutch and after installing electric fans I went back and just dropped the fan settings down several degrees. Fan 1 I set the low to 210f and high to 215f. I set the Fan 2 low to 215 and the high to 220. I just type F to C in the google search and a conversion calculator pulls up at the top of search list. Just enter what temp you want in F and it tells you the temperature in C. Just play with the temp settings if need be. If you find your fans stay on excessively you can always raise the temps back up some.

To change the tablelist: Click on file, mode, advanced

If you could gather used oem parts needed for a really low price from a self pull junk yard or other resource it’s the way to go. I wouldn’t jump in and buy all new and have hundreds of dollars in parts. I think I had a little over $90 in that set up I did in that video. $50 for the fans and 40 for the harness along the front with the fan fuse box. A little more than I wanted to pay but cheaper than people were listed them on marketplace. You having an 03 may need the wider radiator to get the oem fans to fit correctly. I was doing a 2500HD and it had the correct size radiator.

@brandongarnold my 03 Escalade has the LQ9 so I've got the larger radiator luckily. Stapleton42 on RU-vid has a nice video where he installed a factory efan setup on a yukon and also added the factory relay block next to the underhood fuse block. I'd love to go that route and use these free programs to program my pcm. What other software would I need to use? PCM Hammer?

⁠@@michaeltaylor3559 If you download Universal Patcher it automatically comes with a version of PCM Hammer so no need to go to the PCM Hammer page and download it by itself. When you are in Universal Patcher you just go to the Utilities drop down and select what I remember is read/write it will open up PCM Hammer in another window.