C3 Tech/Performance V8 Technical Info, Internal Engine, External Engine, Basic Tech and Maintenance for the C3 Corvette
Sponsored by:
Sponsored by:

temp guage for 1981 vette

Thread Tools
 
Search this Thread
 
Old Mar 5, 2025 | 06:11 PM
  #1  
bclark0609's Avatar
bclark0609
Thread Starter
Heel & Toe
 
Joined: Dec 2024
Posts: 15
Likes: 4
Default temp guage for 1981 vette

I
have watched hours and hours of you tube videos, done everything to this temp gauge except take a hammer to. i post threads done everything that was suggested, still my temp gauge will not work, 2 sending units, 2 BrandNew temp gauges at 100 bucks a piece, if anyone can please help me I don't know what else to do????
Reply
Old Mar 5, 2025 | 07:10 PM
  #2  
4-vettes's Avatar
4-vettes
Race Director
15 Year Member
Liked
Loved
Top Answer: 1
 
Joined: Nov 2006
Posts: 13,330
Likes: 7,901
From: Sunshine Coast, Queensland, Australia
2025 C3 of the Year Finalist - Modified
2024 C3 of the Year Finalist- Modified
2022 C3 of the Year Finalist - Modified
Cruise-In VIII Veteran
Default

I'm not at your house to fix it for you. However, have you tested the wiring? Have you tested the signal wire with a ohm meter? From the end that connects to the sender to the other end that connects to the guage? Do you have power and ground at the guage?
I understand that you feel you have done everything. But clearly your missing something basic here. It's just not a very complicated circuit.
Reply
Old Mar 5, 2025 | 07:19 PM
  #3  
4-vettes's Avatar
4-vettes
Race Director
15 Year Member
Liked
Loved
Top Answer: 1
 
Joined: Nov 2006
Posts: 13,330
Likes: 7,901
From: Sunshine Coast, Queensland, Australia
2025 C3 of the Year Finalist - Modified
2024 C3 of the Year Finalist- Modified
2022 C3 of the Year Finalist - Modified
Cruise-In VIII Veteran
Default

So let's take a look at the temp gauge circuit. This picture is from a 77 manual but your 81 is basically the same.

OK, So we can see our gauge mounted to that awful printed circuit panel. Do we indeed have 12V. Power to the guage? Do we indeed have a good ground? Using a long chunk of wire on our ohm meter, can we determine if we have a good connection from gauge to sender? And also make certain that sender wire is not shorted to ground. And you are checking the sender in the drivers side head? Between cylinders 1 and 3 just behind the alternator?
Reply
Old Mar 5, 2025 | 07:34 PM
  #4  
av81's Avatar
av81
Racer
All Eyes On Me
Liked
Loved
Community Favorite
 
Joined: Mar 2018
Posts: 400
Likes: 53
From: wilmington Ma
Default

What is the gauge reading with key on engine not warmed up? On your temp sender your not messing with the sender on the passenger head with two wires right? That for the electric fan.
Reply
Old Mar 6, 2025 | 06:10 AM
  #5  
bclark0609's Avatar
bclark0609
Thread Starter
Heel & Toe
 
Joined: Dec 2024
Posts: 15
Likes: 4
Default

Originally Posted by 4-vettes
I'm not at your house to fix it for you. However, have you tested the wiring? Have you tested the signal wire with a ohm meter? From the end that connects to the sender to the other end that connects to the guage? Do you have power and ground at the guage?
I understand that you feel you have done everything. But clearly your missing something basic here. It's just not a very complicated circuit.
I am today, I didn't install insulator under screws heard that could short guage out, ohm gauge and was good, the wiring goes into a cluster of other wires,
Reply
Old Mar 6, 2025 | 06:12 AM
  #6  
bclark0609's Avatar
bclark0609
Thread Starter
Heel & Toe
 
Joined: Dec 2024
Posts: 15
Likes: 4
Default

Originally Posted by bclark0609
I am today, I didn't install insulator under screws heard that could short guage out, ohm gauge and was good, the wiring goes into a cluster of other wires,
don't have voltage ⚡️
Reply
Old Mar 6, 2025 | 06:56 AM
  #7  
Bikespace's Avatar
Bikespace
Race Director
Liked
Loved
Community Favorite
Top Answer: 1
 
Joined: Mar 2017
Posts: 11,978
Likes: 4,528
From: Virginia
Default

Have you measured the resistance of the sending unit at different temps? Have you checked the connector that goes into the back of the gauge panel and contacts the (fragile) flexible circuit board? Have you posted photos on the Forum? Have you confirmed your car's operating temp with an IR thermometer?

There could be lots left to do!
Reply
Old Mar 6, 2025 | 07:12 AM
  #8  
bclark0609's Avatar
bclark0609
Thread Starter
Heel & Toe
 
Joined: Dec 2024
Posts: 15
Likes: 4
Default

Originally Posted by Bikespace
Have you measured the resistance of the sending unit at different temps? Have you checked the connector that goes into the back of the gauge panel and contacts the (fragile) flexible circuit board? Have you posted photos on the Forum? Have you confirmed your car's operating temp with an IR thermometer?

There could be lots left to do!
Do not have voltage to guage, going check the ground wire today, i didnt really want to get into the 1 wire is with a cluster of wires going have to dig into and chase the wire. was hoping something more simple!!
Reply
Corvette Stories

The Best of Corvette for Corvette Enthusiasts

story-0

2027 Chevrolet Silverado 1500 First Look: Everything You NEED to Know!

 Michael S. Palmer
story-1

5 Best & 5 Worst Corvette Daily Drivers

 Joe Kucinski
story-2

The Headlights of Every Corvette Generation Explained

 Joe Kucinski
story-3

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

 Joe Kucinski
story-4

Every 2027 Corvette Engine Explained

 Joe Kucinski
story-5

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

 Verdad Gallardo
story-6

10 Ugly Corvettes That We Still Kinda Love

 Joe Kucinski
story-7

Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer

 Brett Foote
story-8

10 Things Every Corvette Owner Needs (2026 Edition)

 Michael S. Palmer
story-9

8 Most "Only Corvette Owners Understand" Quirks and Problems

 Pouria Savadkouei
Old Mar 6, 2025 | 07:42 AM
  #9  
sphil's Avatar
sphil
Pro
All Eyes On Me
Liked
Loved
Community Favorite
 
Joined: Jun 2023
Posts: 524
Likes: 319
From: Western N.C.
Default

Too much teflon tape on sender therefore no ground?
Reply
Old Mar 6, 2025 | 09:18 AM
  #10  
ctmccloskey's Avatar
ctmccloskey
Safety Car
Supporting Lifetime
25 Year Member
Active Streak: 30 Days
Active Streak: 60 Days
Liked
 
Joined: May 2001
Posts: 4,761
Likes: 1,648
From: Fairfax Virginia
Default

Good point there, sphil!

Using anything like Teflon tape or even an anti-seize on the sending unit will make it hard to get a good solid ground. Unless the sending unit touches the coolant I don't put anything on the sending units before screwing them into the block or intake depending on the year Corvette. My C3 has a temperature sender sticking out of the block between cylinders #1 and #3 and this hole doesn't have any coolant access. On the top of my intake there is a sending unit used to measure the coolant temperature and I sparingly apply PTFE Paste on a couple of the threads. It helps to go back and enure the sending unit is grounded properly.

Is the engine grounded properly? Take a multi-meter and read the voltage at the battery. Then take the meter and read the voltage between the alternator output and the engine block, the numbers should be either the same or very, very close, if the ground is working okay. A poorly grounded engine can cause grief for electrical sending units as they depend in part on the engine's having a perfect ground.

I count myself to be Lucky not having any flexible printed circuit boards in my C3. My C3 is a early 1968 and is just as simple as it could be, which to me is a big Plus.
Reply
Old Mar 6, 2025 | 10:59 AM
  #11  
bclark0609's Avatar
bclark0609
Thread Starter
Heel & Toe
 
Joined: Dec 2024
Posts: 15
Likes: 4
Default

Originally Posted by Bikespace
Have you measured the resistance of the sending unit at different temps? Have you checked the connector that goes into the back of the gauge panel and contacts the (fragile) flexible circuit board? Have you posted photos on the Forum? Have you confirmed your car's operating temp with an IR thermometer?

There could be lots left to do!
1all the above
Reply

Get notified of new replies

To temp guage for 1981 vette





All times are GMT -4. The time now is 08:30 AM.

story-0
2027 Chevrolet Silverado 1500 First Look: Everything You NEED to Know!

Slideshow: Is the 2027 Chevrolet Silverado 1500 the best Silverado yet?

By Michael S. Palmer | 2026-06-16 08:01:12


VIEW MORE
story-1
5 Best & 5 Worst Corvette Daily Drivers

Slideshow: 5 best and 5 worst Corvette daily drivers

By Joe Kucinski | 2026-06-15 10:32:13


VIEW MORE
story-2
The Headlights of Every Corvette Generation Explained

Slideshow: The headlights of every Corvette generation explained

By Joe Kucinski | 2026-06-15 10:17:14


VIEW MORE
story-3
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-4
Every 2027 Corvette Engine Explained

Slideshow: Every 2027 Corvette engine explained

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


VIEW MORE
story-5
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-6
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-7
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-8
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-9
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