What The Heck Is This Thing? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Guardrail · 12-08-2005, 11:29 PM

I removed this thing from the inside of the firewall, just above the fuse box in my 71'. I thought it was an old relay for the TCS, as I can hear a relay click under the dash when my TH350 shifts into 3rd gear.

Funny thing is, I still hear the clicking just like before. Even though I removed it from the truck.

Green Machine · 12-09-2005, 12:13 AM

I think that is your horn relay.

3100 special · 12-09-2005, 12:18 AM

Yep, that's what it is.

**truckdude239** · 12-09-2005, 02:02 AM

**pjmoreland** · 12-09-2005, 04:48 AM

I stole this picture from a thread started by rick980. It shows the TCS relay and the horn relay. They are right next to each other. If you hear it clicking when your transmission shifts, then I'm guessing it's the TCS relay activating the vacuum advance disable valve. The picture you posted looks like the horn relay though. Did you notice another relay right next to it?

Guardrail · 12-09-2005, 02:39 PM

Well, you guys are right. The horn no longer works (I hadn't noticed). I guess I'd better reinstall that relay and remove the one above it. Thanks for the help guys.

12-08-2005, 11:29 PM	#1
Guardrail And Don't Call Me Shirley Join Date: Oct 2005 Location: Cameron Park, CA Posts: 115	What The Heck Is This Thing? I removed this thing from the inside of the firewall, just above the fuse box in my 71'. I thought it was an old relay for the TCS, as I can hear a relay click under the dash when my TH350 shifts into 3rd gear. Funny thing is, I still hear the clicking just like before. Even though I removed it from the truck. Attached Images __________________ Rick Tucker 1969 C20/Custom Camper (the Green Machine)Sold 1970 GMC 4000 COE (future Ramp Truck) 1972 K10 Longbed (restoration begins June 2020)

12-09-2005, 12:13 AM	#2
Green Machine Senior Member Join Date: Jul 2004 Location: Estherville, Iowa Posts: 3,371	Re: What The Heck Is This Thing? I think that is your horn relay. __________________ 1968 C10 307 3spd Long Fleet ------ http://67-72chevytrucks.com/vboard/s...d.php?t=201103 1970 C10 305 Super T10 Long Fleet --- http://67-72chevytrucks.com/vboard/s...d.php?t=202285 1971 C20 383 TH350 Dana Posi ----- http://67-72chevytrucks.com/vboard/s...d.php?t=206894 2001 GMC Sierra 1500 C3 6.0

12-09-2005, 12:18 AM	#3
3100 special Street Rod Dreamin' Join Date: Feb 2004 Location: Work:Batam, Indonesia/ Home:League City, Texas Posts: 1,241	Re: What The Heck Is This Thing? Yep, that's what it is. __________________ 1954 Chevy 3100 Panel Truck 2004 GMC Yukon 2007 GMC Sierra 4X4 "I am for doing good to the poor, but I differ in opinion of the means. I think the best way of doing good to the poor, is not making them easy in poverty, but leading or driving them out of it." Benjamin Franklin, On the Price of Corn and Management of the Poor, November 1776

12-09-2005, 02:02 AM	#4
truckdude239 Senior Member Join Date: Sep 2005 Location: Lewisville, Nc Posts: 10,237	Re: What The Heck Is This Thing? __________________ 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

12-09-2005, 04:48 AM	#5
pjmoreland Senior Member Join Date: Jan 2005 Location: CA Posts: 5,982	Re: What The Heck Is This Thing? I stole this picture from a thread started by rick980. It shows the TCS relay and the horn relay. They are right next to each other. If you hear it clicking when your transmission shifts, then I'm guessing it's the TCS relay activating the vacuum advance disable valve. The picture you posted looks like the horn relay though. Did you notice another relay right next to it? Attached Images Last edited by pjmoreland; 12-09-2005 at 04:50 AM.

12-09-2005, 02:39 PM	#6
Guardrail And Don't Call Me Shirley Join Date: Oct 2005 Location: Cameron Park, CA Posts: 115	Re: What The Heck Is This Thing? Well, you guys are right. The horn no longer works (I hadn't noticed). I guess I'd better reinstall that relay and remove the one above it. Thanks for the help guys. __________________ Rick Tucker 1969 C20/Custom Camper (the Green Machine)Sold 1970 GMC 4000 COE (future Ramp Truck) 1972 K10 Longbed (restoration begins June 2020)



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