C3 General General C3 Corvette Discussion not covered in Tech
Sponsored by:
Sponsored by:

What is this plug for?

Thread Tools
 
Search this Thread
 
Old Apr 26, 2015 | 06:46 PM
  #1  
Matty Gritt's Avatar
Matty Gritt
Thread Starter
Advanced
 
Joined: Sep 2014
Posts: 64
Likes: 6
Default What is this plug for?

I'm doing some wiring on my 78 Corvette. Wondering what exactly this plug is for. I removed a rusted out component from it, it has 4 prongs that plug into it. Any help is appreciated! Thanks!

Name:  image-1854897838.jpg
Views: 461
Size:  426.1 KB
Reply
Old Apr 26, 2015 | 07:27 PM
  #2  
JimLentz's Avatar
JimLentz
Melting Slicks
Supporting Lifetime
10 Year Member
 
Joined: Jan 2014
Posts: 2,478
Likes: 254
From: Downers Grove Illinois
Default

Sounds like a relay. Do you have a picture of what you pulled out?
Reply
Old Apr 26, 2015 | 07:36 PM
  #3  
Matty Gritt's Avatar
Matty Gritt
Thread Starter
Advanced
 
Joined: Sep 2014
Posts: 64
Likes: 6
Default

Okay here is a pic of it. I removed the covering off, it just sort of fell off. It's from right underneath the steering column.


Name:  image-1090877032.jpg
Views: 394
Size:  641.5 KB
*The unknown piece and the cover that fell off it.

Name:  image-2053094909.jpg
Views: 367
Size:  550.3 KB
*One of the prongs broke off in the connector.

I'm not sure what it is or what it does.
Reply
Old Apr 26, 2015 | 08:24 PM
  #4  
The13Bats's Avatar
The13Bats
Race Director
20 Year Member
Liked
Loved
Community Favorite
 
Joined: Mar 2003
Posts: 11,608
Likes: 780
From: Eustis ( Area 51 Bat Cave ) Fl
Default

It's a factory style relay...horn? alarm? heater? perhaps power window?

Last edited by The13Bats; Apr 26, 2015 at 08:39 PM.
Reply
Old Apr 27, 2015 | 12:10 PM
  #5  
JimLentz's Avatar
JimLentz
Melting Slicks
Supporting Lifetime
10 Year Member
 
Joined: Jan 2014
Posts: 2,478
Likes: 254
From: Downers Grove Illinois
Default

Originally Posted by The13Bats
It's a factory style relay...horn? alarm? heater? perhaps power window?
Reply
Old Apr 27, 2015 | 01:27 PM
  #6  
Matty Gritt's Avatar
Matty Gritt
Thread Starter
Advanced
 
Joined: Sep 2014
Posts: 64
Likes: 6
Default

I'm trying to find out what kind of relay it is. And I've had no luck. I haven't even cranked the engine over yet. It was a roller. I put the car "On" and my turn signals will come on but not blink. I looked up a turn signal relay but it's not this. So I've got two issues now I guess.
Reply
Old Apr 27, 2015 | 01:43 PM
  #7  
JimLentz's Avatar
JimLentz
Melting Slicks
Supporting Lifetime
10 Year Member
 
Joined: Jan 2014
Posts: 2,478
Likes: 254
From: Downers Grove Illinois
Default

Check page 3 of this pdf, looks like your power window relay.
Reply
Old Apr 27, 2015 | 01:48 PM
  #8  
phat87's Avatar
phat87
Pro
20 Year Member
Conversation Starter
All Eyes On Me
 
Joined: Feb 2006
Posts: 671
Likes: 10
2021 C4 of the Year - Unmodified Finalist
Default Hmmm

I would say that relay will require some clean-up. Sorry dumb I know.

I will have a look in my AIM (it's at the shop).

Regarding your signals. If they come on but don't blink it may very well be a ground wire issue. Make sure the engine is grounded to the frame, the dash is grounded to the engine (or frame) and the frame is grounded to the battery.

Your ground wire probably goes from the battery to the alternator bracket, but the engine will not ground to the frame because it is all rubber mounted so needs a good ground for the engine to the frame.
Reply
Corvette Stories

The Best of Corvette for Corvette Enthusiasts

story-0

5 Best & 5 Most Overrated Corvette Track Packages of All Time!

 Joe Kucinski
story-1

Every 2027 Corvette Engine Explained

 Joe Kucinski
story-2

Designer Imagines A Corvette That Looks More Like a Corvette Than the Corvette

 Verdad Gallardo
story-3

10 Ugly Corvettes That We Still Kinda Love

 Joe Kucinski
story-4

Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer

 Brett Foote
story-5

10 Things Every Corvette Owner Needs (2026 Edition)

 Michael S. Palmer
story-6

8 Most "Only Corvette Owners Understand" Quirks and Problems

 Pouria Savadkouei
story-7

10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years

 Joe Kucinski
story-8

How Much Horsepower Every Corvette Engine "LOST" in 1972

 Joe Kucinski
story-9

Top 10 DOs and DON'Ts for Protecting Your Convertible Top!

 Michael S. Palmer
Old Apr 27, 2015 | 05:56 PM
  #9  
The13Bats's Avatar
The13Bats
Race Director
20 Year Member
Liked
Loved
Community Favorite
 
Joined: Mar 2003
Posts: 11,608
Likes: 780
From: Eustis ( Area 51 Bat Cave ) Fl
Default

My eyes bugging me and having trouble looking at it, but try this,

https://sites.google.com/a/c3vrmail....iring-diagrams

He has wiring diagrams posted...find the relay or wires in a plug on the diagram...
Reply
Old Apr 27, 2015 | 10:45 PM
  #10  
Xliberater's Avatar
Xliberater
Advanced
 
Joined: Aug 2010
Posts: 87
Likes: 0
From: Brunswick GA
Default

I have that same plug in my 81 and have always wondered what it was for. Right now mine isn't connected to anything either. I looked over a few of my diagrams and believe that the plug is for either the rear defogger or the alarm system. I have never found the relay that it is supposed to connect to and it is likely that a previous owner removed it a long time ago.

Hopefully a wiring expert can clear this up for us.
Reply
Old Apr 28, 2015 | 03:23 PM
  #11  
The13Bats's Avatar
The13Bats
Race Director
20 Year Member
Liked
Loved
Community Favorite
 
Joined: Mar 2003
Posts: 11,608
Likes: 780
From: Eustis ( Area 51 Bat Cave ) Fl
Default

The blades on the rust relay most look like rear defroster relay to me..


Not like power window relay, different blades and mounting tab,

Last edited by The13Bats; Apr 28, 2015 at 03:51 PM.
Reply
Old Apr 28, 2015 | 03:54 PM
  #12  
Matty Gritt's Avatar
Matty Gritt
Thread Starter
Advanced
 
Joined: Sep 2014
Posts: 64
Likes: 6
Default

Defroster relay! That's what it looks like, time to buy one! Thanks for the help 13bats!!
Reply
Old Apr 28, 2015 | 04:42 PM
  #13  
The13Bats's Avatar
The13Bats
Race Director
20 Year Member
Liked
Loved
Community Favorite
 
Joined: Mar 2003
Posts: 11,608
Likes: 780
From: Eustis ( Area 51 Bat Cave ) Fl
Default

Originally Posted by Matty Gritt
Defroster relay! That's what it looks like, time to buy one! Thanks for the help 13bats!!


On a side note...how did it get so rusty looks like it was under water?
Reply
Old Apr 29, 2015 | 12:12 PM
  #14  
Xliberater's Avatar
Xliberater
Advanced
 
Joined: Aug 2010
Posts: 87
Likes: 0
From: Brunswick GA
Default

Regarding the plug mentioned in the first post, I believe all 4 prongs are horizontal to one another (that is how it is setup in my 81). Looking at that relay it has both horizontal and vertical pins.

Would that plug fit the defogger relay in an 81 or was there a different relay for that year?

Last edited by Xliberater; Apr 29, 2015 at 12:21 PM.
Reply
Old Apr 29, 2015 | 02:53 PM
  #15  
speedreed8's Avatar
speedreed8
Melting Slicks
15 Year Member
Liked
Loved
Community Favorite
 
Joined: Oct 2006
Posts: 2,417
Likes: 336
From: Texas
Default

the plug matches the schematic for the rear window defogger timer relay. looks as if that relay may have had 4 prongs, one has rusted off. that thing been soaking in water?
http://www.corvetteforum.net/c3/tune.../index20.shtml
Reply
Old Apr 29, 2015 | 03:01 PM
  #16  
The13Bats's Avatar
The13Bats
Race Director
20 Year Member
Liked
Loved
Community Favorite
 
Joined: Mar 2003
Posts: 11,608
Likes: 780
From: Eustis ( Area 51 Bat Cave ) Fl
Default

Did my reply and the pictures I posted not show up to all?
Reply

Get notified of new replies

To What is this plug for?





All times are GMT -4. The time now is 10:40 AM.

story-0
5 Best & 5 Most Overrated Corvette Track Packages of All Time!

Slideshow: The 5 best and 5 most overrated Corvette track packages ever.

By Joe Kucinski | 2026-06-09 12:46:45


VIEW MORE
story-1
Every 2027 Corvette Engine Explained

Slideshow: Every 2027 Corvette engine explained

By Joe Kucinski | 2026-06-09 12:16:31


VIEW MORE
story-2
Designer Imagines A Corvette That Looks More Like a Corvette Than the Corvette

Slideshow: A Jaguar designer's personal project imagines what a modern front-engined Corvette might look like if Chevrolet revisited the golden age of the Stingray.

By Verdad Gallardo | 2026-06-08 19:53:43


VIEW MORE
story-3
10 Ugly Corvettes That We Still Kinda Love

Slideshow: 10 ugly Corvettes that we still kinda love.

By Joe Kucinski | 2026-06-03 10:34:17


VIEW MORE
story-4
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer

A lot of money has changed hands at the online auction house over the years.

By Brett Foote | 2026-06-03 10:21:50


VIEW MORE
story-5
10 Things Every Corvette Owner Needs (2026 Edition)

Slideshow: 10 great gifts Corvette enthusiasts actually want for Father's Day!

By Michael S. Palmer | 2026-06-03 15:43:40


VIEW MORE
story-6
8 Most "Only Corvette Owners Understand" Quirks and Problems

Slideshow: These are the quirks, annoyances, and oddly lovable problems that every Corvette owner eventually learns to live with.

By Pouria Savadkouei | 2026-05-28 09:31:39


VIEW MORE
story-7
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years

Slideshow: 10 reasons why the C6 Z06 is still a performance benchmark after 20 years.

By Joe Kucinski | 2026-05-27 17:20:09


VIEW MORE
story-8
How Much Horsepower Every Corvette Engine "LOST" in 1972

Slideshow: How much horsepower every Corvette engine lost in 1972.

By Joe Kucinski | 2026-05-27 16:54:53


VIEW MORE
story-9
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!

Slideshow: How to Protect A Convertible Top: 10 DOs & DON'Ts

By Michael S. Palmer | 2026-04-03 00:00:00


VIEW MORE