Name that doohickey... - The 1947 - Present Chevrolet & GMC Truck Message Board Network

GoaterAz · 01-28-2014, 09:04 PM

Go easy guys, first build…this wasn't connected to anything.

My uneducated guess would be for the reverse lights? a complete guess.

It was mounted to the firewall (original white paint in the picture) and one pigtail was snipped and the other led to a rubber connector that was halfway down the frame just hanging out waiting to confuse me.

**LockDoc** · 01-28-2014, 09:14 PM

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I believe that would be part of the emissions system. What year truck?

LockDoc

ERASER5 · 01-28-2014, 10:04 PM

Doc hit it. TSC--transmission spark control. The system kept the vacuum advance locked out until the engine was above 32° F and the trans in high gear. The was a switch in the trans, a switch in the passenger head, a relay (pictured) and a vacuum switch mounted next to the carb. None of which needs to be kept.

SS Tim · 01-28-2014, 10:12 PM

That would be a relay for the transmission controlled spark (TCS).
Take a look in the service manual(section 6) for the full story but the short version is it denies spark advance in all but high gear when the vehicle is warm (above 65 to 232*).

GoaterAz · 01-28-2014, 10:22 PM

You 3 guys should all fly out to Arizona and I will walk around pointing at things and you guys can give me the answers and we will high five and drink beer. Haha...

GoaterAz · 01-28-2014, 10:23 PM

Quote:

Originally Posted by LockDoc

-
I believe that would be part of the emissions system. What year truck?

LockDoc

It's a 1970, from the factory it had a 307, 3speed on the column.

Now it has a 350, 4 speed manual.

**LockDoc** · 01-28-2014, 10:29 PM

Quote:

Originally Posted by GoaterAz

You 3 guys should all fly out to Arizona and I will walk around pointing at things and you guys can give me the answers and we will high five and drink beer. Haha...

Don't tempt me...

LockDoc

**jabborabbo** · 01-28-2014, 10:42 PM

Quote:

Originally Posted by GoaterAz

You 3 guys should all fly out to Arizona and I will walk around pointing at things and you guys can give me the answers and we will high five and drink beer. Haha...

If you pay for the beer I'll fly out and spend a week or two giving you answers...the answers will all be suspect, but we can just blame the beer for that!

tommys72 · 01-28-2014, 10:55 PM

Quote:

Originally Posted by jabborabbo

If you pay for the beer I'll fly out and spend a week or two giving you answers...the answers will all be suspect, but we can just blame the beer for that!

^^ thats good!!

BigCountryx · 01-28-2014, 11:15 PM

Haha. I had the same thread that I started a while back.

http://67-72chevytrucks.com/vboard/s...d.php?t=605063

My question now is that could it also be part of the backup lamp as the OP eluded to? Everyone keeps telling me that the reverse switch is on the tranny (3 on da tree) but the only wire or connector on my tranny is connected the the TCS.

**special-K** · 01-29-2014, 10:22 AM

Will you give me a truck is answer all your beer questions? I don't drink beer often. But when I do I'm an expert! With enough whiskey I'd prolly try to convince you I designed these danged things!

GoaterAz · 01-31-2014, 11:10 PM

Quote:

Originally Posted by special-K

Will you give me a truck is answer all your beer questions? I don't drink beer often. But when I do I'm an expert! With enough whiskey I'd prolly try to convince you I designed these danged things!

You guys are cracking me up haha.

Quote:

Originally Posted by BigCountryx

Haha. I had the same thread that I started a while back.

http://67-72chevytrucks.com/vboard/s...d.php?t=605063

My question now is that could it also be part of the backup lamp as the OP eluded to? Everyone keeps telling me that the reverse switch is on the tranny (3 on da tree) but the only wire or connector on my tranny is connected the the TCS.

Can anyone help out with this? I'd be curious too.

SS Tim · 01-31-2014, 11:57 PM

I'll try to find some time but it will probably be Monday. Just got something dumped in my inbox that needs lookin' after. PM a reminder if you don't see something by Tuesday.

**70STOVEBOLT** · 02-01-2014, 01:09 PM

Backup light switch is located on the steering column I think..?

01-28-2014, 09:04 PM	#1
GoaterAz Registered User Join Date: Sep 2012 Location: Arizona Posts: 222	Name that doohickey... Go easy guys, first build…this wasn't connected to anything. My uneducated guess would be for the reverse lights? a complete guess. It was mounted to the firewall (original white paint in the picture) and one pigtail was snipped and the other led to a rubber connector that was halfway down the frame just hanging out waiting to confuse me. __________________ You remember when drinking too many beers was a bad idea? Me neither.

01-28-2014, 09:14 PM	#2
LockDoc The Older Generation Join Date: Aug 2006 Location: Montezuma, Iowa Posts: 25,818	Re: Name that doohickey... - I believe that would be part of the emissions system. What year truck? LockDoc __________________ Leon Locksmith, Specializing In Antique Trucks, Automobiles, & Motorcycles (My Dually Pickup Project Thread) http://67-72chevytrucks.com/vboard/s...d.php?t=829820 -

01-28-2014, 10:04 PM	#3
ERASER5 Registered User Join Date: Jun 2006 Location: Indiana Posts: 4,859	Re: Name that doohickey... Doc hit it. TSC--transmission spark control. The system kept the vacuum advance locked out until the engine was above 32° F and the trans in high gear. The was a switch in the trans, a switch in the passenger head, a relay (pictured) and a vacuum switch mounted next to the carb. None of which needs to be kept. __________________ '70 GMC C1500 LWB Power disc brakes. WooHoo! Posi 6 Lug Dana 60

01-28-2014, 10:12 PM	#4
SS Tim Registered User Join Date: Aug 2010 Location: Edwards, CA Posts: 7,503	Re: Name that doohickey... That would be a relay for the transmission controlled spark (TCS). Take a look in the service manual(section 6) for the full story but the short version is it denies spark advance in all but high gear when the vehicle is warm (above 65 to 232). __________________ Thanks, Tim VIN/Model Decoders * Power Team Charts (engine/transmission/gear ratio) * Post Your Pickup SPID Blazer SPID Suburban/Panel SPID * RTFM ... Read The Factory Manuals... download 'em here Highlanders Do you have a 1972 Plaid Pickup? Plaid Blazer ** Plaid Suburban Last edited by SS Tim; 01-28-2014 at 10:52 PM.

01-28-2014, 10:22 PM	#5
GoaterAz Registered User Join Date: Sep 2012 Location: Arizona Posts: 222	Re: Name that doohickey... You 3 guys should all fly out to Arizona and I will walk around pointing at things and you guys can give me the answers and we will high five and drink beer. Haha... __________________ You remember when drinking too many beers was a bad idea? Me neither.

01-28-2014, 11:15 PM	#10
BigCountryx Registered User Join Date: May 2009 Location: Gonzales, LA Posts: 779	Re: Name that doohickey... Haha. I had the same thread that I started a while back. http://67-72chevytrucks.com/vboard/s...d.php?t=605063 My question now is that could it also be part of the backup lamp as the OP eluded to? Everyone keeps telling me that the reverse switch is on the tranny (3 on da tree) but the only wire or connector on my tranny is connected the the TCS. __________________ 1972 Pale Yella 2WD Blazer ..... 350HO/700R4.... '68 Clipped 1970 Original Paint SWB Farm Truck ..... 5.3/4L80.... 2x HRPT Participant

01-29-2014, 10:22 AM	#11
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,851	Re: Name that doohickey... Will you give me a truck is answer all your beer questions? I don't drink beer often. But when I do I'm an expert! With enough whiskey I'd prolly try to convince you I designed these danged things! __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

01-31-2014, 11:57 PM	#13
SS Tim Registered User Join Date: Aug 2010 Location: Edwards, CA Posts: 7,503	Re: Name that doohickey... I'll try to find some time but it will probably be Monday. Just got something dumped in my inbox that needs lookin' after. PM a reminder if you don't see something by Tuesday. __________________ Thanks, Tim * VIN/Model Decoders * Power Team Charts (engine/transmission/gear ratio) * Post Your Pickup SPID Blazer SPID Suburban/Panel SPID * RTFM ... Read The Factory Manuals... download 'em here Highlanders Do you have a 1972 Plaid Pickup? Plaid Blazer ** Plaid Suburban

02-01-2014, 01:09 PM	#14
70STOVEBOLT Senior Member Join Date: Jun 2005 Location: Winona Lake, IN Posts: 6,424	Re: Name that doohickey... Backup light switch is located on the steering column I think..? __________________ 70 C/10 SWB 402/TH400/3.73 "The Needy Beast" 200,000 Mile Club Disc Brake Club Owner installed options: Front Sway Bar Power Steering Power Brakes Cigar Lighter Courtesy Lights Deluxe Side Markers Wiper Delay Sliding Rear Window Power Windows Power Locks Sniper EFI 2015 Silverado 1500 LS 4.3/6L80/3.23 lowered 2" front & rear



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