Alrighty so I will be putting in my electric fans sometime this week hopefully, and the easiest way to activate them would be with a tech 2. I already have a tune (wait4me), but he doesnt like to answer emails and Im not looking forward to the 2 week downtime it would take to send it in. The cost of shipping will run me around $20 anyway, so if I can get it done at the dealer (tech2) for around that or less (.5 hours minimum), then I'll e happy.
The problem is, the dealership and the one other shop with a tech 2 thinks im nuts and it wont work so they wont even touch it. So, if anyone has experience with a tech 2 or has access to one and knows how to turn the electric fan option on and set the on/off temps, I would tremendously appreciate a walkthrough I can print out for them so I can get it done.

I made my harness today following this diagram:



And is this right for the on/off settings:

low:
coolant temp >202
a/c > 210

high:
coolant temp > 220
a/c > 265

Also, can they be set to turn off if I exceed 40mph with a tech2 (I know you can with hpt or efilive)? If not I can just wire in a toggle switch.

Thanks.

 

Oh and the fans are LS1 fans and I have an 04 chevy silverado.

 

....mmk, well I have them setup manually for now with a dpdt switch in the cab...

install is here if anyone is interested: http://www.fullsizechevy.com/forums/...ml#post3286650

 

Pretty cool...sure are alot of switches lol. I just wired 2 switches into my Nelson harness to defeat the high speed fans when the ac compressor kicks on, and to manually activate the high speed fans. I also have an LED that lets me know when the PCM has commanded the fans on. My truck is a 99, so I only have pin 42 in use, no pin 33 for me.

Sorry I don't have the answers to your question though....I have read about guys using HPtuners and EFI Live, but haven't heard anything about the TechII.

 

tech 2 wont work without a PCM out of a vehical with efans or a VCI number from GM technical support, and GM only will do a VCI number for a technical issue with a new car/truck

the VCI is where GM technical support goes in and does almost like a custom program for you and then the dealer can download the tune in TIS2web- the reflashing program for the dealer

but like i said- they wont just change software for a tune, you can energize the pcm output with it- but only for a service test, they will shut off once you exit out of the tech II screen

dont hold me to this 100%, but im a tech at a dealer, and me and a couple guys tried messing around with this for a while and it wouldnt work- i ended up with hptuners

 

Ah thanks, that was an answer I was looking for. Everyone I've asked said it cant be done, but I know there are options in the Tech2 for efans, I just didnt know what they did.

budhayes3, yea, I like switches : )
The switches on the left are for my bumper lights, reverse lights, and fans respecitvely. The 4 switches closer to the steering wheel are for my air horns, while the rocker is a master accessory on/off. I have 3 more rockers in the center under the vent for my two air compressors, and one to tie my stock horn in with my air horn.

 

The 99 PCM's have a fan output??

I thought only the 02 up PCM's had this?

 

They do, pin 33 is just in use as Auto Recirculation instead of Fan #2 control. Just need to alter that setting and swap the pin out.