What is this box doing? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Stepper86 · 04-03-2014, 05:19 AM

I bought a complete drive line out of a 2004 2500HD for my 1986 Stepside.
The electrical system from the donor truck came in a big box together with misc parts.
Im going to use a new harness for my truck so most of the stuff I will probably not use. When I went trough the parts I found this little black box togeter with the ECM. Anyone that can tell me what it´s for, and do I need it?

**PGSigns** · 04-03-2014, 06:13 AM

TAC module for the drive by wire.
Jimmy

**truckdude239** · 04-03-2014, 07:55 AM

That is the tac module for the dbw pedal and thottle body so yes u need it

ls1nova71 · 04-03-2014, 09:26 AM

As the other stated, its the Throttle Actuator Control (TAC) module. However, that one is for a 2000-2002, not a 2004, so it may not work for you. Are you sure your engine is an 04?

littlevictories · 04-03-2014, 10:00 AM

the pcm is for 03-07 so it might be

Stepper86 · 04-03-2014, 12:11 PM

Thanks for the replies! I had an idea that it would be needed.
I was not there my self when it got pulled out of the donor truck, but I'm quite sure that it is the unit out of the 2004. But I will check with the seller just to be sure.

TwinsSpeedShop · 04-13-2014, 10:25 AM

All of it needs to be out of the same vehicle or headaches abound!! Or at least from the same year. Tach module, pedal, and computer have to all match or this get screwy. Make sure when u take to the supplier that all if it matches and it will all go smoother

Stepper86 · 04-14-2014, 05:14 PM

I had a chat with the guy, he took pictures of everything when he took the donnor truck apart. He sent me the pictures so it's clear that it came from the same truck. The truck was drivable (hit on the side) he even had a short video of it running.
So I think it will be ok.

04-03-2014, 05:19 AM	#1
Stepper86 Registered User Join Date: Sep 2011 Location: Stockholm Posts: 263	What is this box doing? I bought a complete drive line out of a 2004 2500HD for my 1986 Stepside. The electrical system from the donor truck came in a big box together with misc parts. Im going to use a new harness for my truck so most of the stuff I will probably not use. When I went trough the parts I found this little black box togeter with the ECM. Anyone that can tell me what it´s for, and do I need it? Attached Images __________________ Tom.______________________________________ The fleet: 2007 BMW 530xi M (daily driver) 1986 C-10 Stepside (project "my time") 1992 Corvette cab (summer time daily driver) 1969 Cadilac DeVille Cab ("it just need some paint")

04-03-2014, 06:13 AM	#2
PGSigns Senior Member Join Date: Jan 2011 Location: Hayes Va Posts: 4,569	Re: What is this box doing? TAC module for the drive by wire. Jimmy __________________ 60 to 66 Chevy and GMC window decals http://67-72chevytrucks.com/vboard/s...d.php?t=661131 Good friends, good food and a hotrod what else do you need? 1966 BBW long fleet Daily driver 1965 BBW short fleet Sold and going to a good home 1965 Suburban 2003 3500 Duramax 2005 Ultra Classic

04-03-2014, 07:55 AM	#3
truckdude239 Senior Member Join Date: Sep 2005 Location: Lewisville, Nc Posts: 10,230	Re: What is this box doing? That is the tac module for the dbw pedal and thottle body so yes u need it __________________ David fuller Ase Certified Mechanic Click here to help support our board!! 1971 Chevy c-10 under going a 4.8l LSx swap Build Thread http://67-72chevytrucks.com/vboard/s...d.php?t=421305 2007 Honda Accord my daily 145kmiles 2002 Honda Accord 4 door With 330k(sisters car) 2005 toyota Avalon 228k( brothers car) 2002 Sububran 5.3 245k 2000 Tahoe 5.3l 378 General manager for Marco's Carwash & lube

04-03-2014, 09:26 AM	#4
ls1nova71 Registered User Join Date: Dec 2009 Location: Independence Mo Posts: 4,118	Re: What is this box doing? As the other stated, its the Throttle Actuator Control (TAC) module. However, that one is for a 2000-2002, not a 2004, so it may not work for you. Are you sure your engine is an 04? __________________ My '72 short bed build. http://www.ls1tech.com/forums/conver...6-0-4l80e.html 5.3 swap into my RUSTY '71 C10 http://ls1tech.com/forums/conversion...71-c-10-a.html

04-03-2014, 10:00 AM	#5
littlevictories Registered User Join Date: Dec 2013 Location: Portland, Ore. Posts: 348	Re: What is this box doing? the pcm is for 03-07 so it might be

04-03-2014, 12:11 PM	#6
Stepper86 Registered User Join Date: Sep 2011 Location: Stockholm Posts: 263	Re: What is this box doing? Thanks for the replies! I had an idea that it would be needed. I was not there my self when it got pulled out of the donor truck, but I'm quite sure that it is the unit out of the 2004. But I will check with the seller just to be sure. __________________ Tom.______________________________________ The fleet: 2007 BMW 530xi M (daily driver) 1986 C-10 Stepside (project "my time") 1992 Corvette cab (summer time daily driver) 1969 Cadilac DeVille Cab ("it just need some paint")

04-13-2014, 10:25 AM	#7
TwinsSpeedShop Registered User Join Date: Mar 2014 Location: Easley SC Posts: 150	Re: What is this box doing? All of it needs to be out of the same vehicle or headaches abound!! Or at least from the same year. Tach module, pedal, and computer have to all match or this get screwy. Make sure when u take to the supplier that all if it matches and it will all go smoother

04-14-2014, 05:14 PM	#8
Stepper86 Registered User Join Date: Sep 2011 Location: Stockholm Posts: 263	Re: What is this box doing? I had a chat with the guy, he took pictures of everything when he took the donnor truck apart. He sent me the pictures so it's clear that it came from the same truck. The truck was drivable (hit on the side) he even had a short video of it running. So I think it will be ok. __________________ Tom.______________________________________ The fleet: 2007 BMW 530xi M (daily driver) 1986 C-10 Stepside (project "my time") 1992 Corvette cab (summer time daily driver) 1969 Cadilac DeVille Cab ("it just need some paint")



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