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  • 1965 - 1973 Classic Mustangs -General/Talk-
  • Classic Mustang Specific Tech

temp sending unit

  • Thread starter Thread starter 66moneypit
  • Start date Start date Aug 1, 2006
6

66moneypit

Member
Dec 28, 2004
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Northern Va
Aug 1, 2006
#1
  • Aug 1, 2006
  • #1
Every once in a while I noticed my temp gauge would max out and then go back down. It was totally random of when it would happen. Well I was screwing around and I noticed connection to the sending unit was incredibly loose. I mean there was no resistance when pulling it off the connector.

What's the best way to fix that so it's tighter ?
 

Vinyl66

Member
Mar 21, 2004
398
0
16
Aug 1, 2006
#2
  • Aug 1, 2006
  • #2
Use a ring type electrical connector and a small nut to hold it down.
 

67 GTA

Member
Feb 7, 2003
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16
Frankln, Kentucky
Aug 1, 2006
#3
  • Aug 1, 2006
  • #3
Are you talking about one of the black 90 degree boots that slide on?
 

Max Power

Active Member
Jul 31, 2003
1,774
1
36
St Paul
Aug 1, 2006
#4
  • Aug 1, 2006
  • #4
Pinch the boot with a pliers and reinstall.
 
6

66moneypit

Member
Dec 28, 2004
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Northern Va
Aug 1, 2006
#5
  • Aug 1, 2006
  • #5
67 GTA said:
Are you talking about one of the black 90 degree boots that slide on?
Click to expand...

Exactly.... could that explain the gauge behavior ?
 

67 GTA

Member
Feb 7, 2003
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Frankln, Kentucky
Aug 1, 2006
#6
  • Aug 1, 2006
  • #6
Yes, they get worn inside and won't get a good contact. There may be something else wrong, but I would start there. Cut it off and do what Vinyl66 said. Don't try to squeeze it together, it will have an even worse connection.
 
6

66moneypit

Member
Dec 28, 2004
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Northern Va
Aug 1, 2006
#7
  • Aug 1, 2006
  • #7
Vinyl66 said:
Use a ring type electrical connector and a small nut to hold it down.
Click to expand...

Just cut the existing connector and use a ring connector ? I will check to sending unit to make sure it has threads.
 

Jester67

Member
Sep 21, 2004
908
1
18
TN
Aug 1, 2006
#8
  • Aug 1, 2006
  • #8
If the gauge is pegging out it is because the wire is getting shorted not because it is lose. The way they work is as the temperature increased the resistance decreases. A disconnected “ loose” connection would give you no reading at all.
 

67 GTA

Member
Feb 7, 2003
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Frankln, Kentucky
Aug 1, 2006
#9
  • Aug 1, 2006
  • #9
Jester may beon to something here. I ground my gauges out to make sure they aren't the problem and they do max out when they are working properly.
 

Jester67

Member
Sep 21, 2004
908
1
18
TN
Aug 1, 2006
#10
  • Aug 1, 2006
  • #10
67 GTA said:
Jester may beon to something here. I ground my gauges out to make sure they aren't the problem and they do max out when they are working properly.
Click to expand...
Mom would be so proud 4 years of collage is finally paying off.
 

zookeeper

Founding Member
Aug 25, 2001
3,415
63
109
Rogue River, Oregon
Aug 1, 2006
#11
  • Aug 1, 2006
  • #11
This kinda reminds me of my last truck. The oil pressure guage read "0" pretty much all the time, and anytime someone else drove it, they'd panic. I always got the same question, "what makes you think it's just the gauge or sending unit?" I always figured it had to be since it never made any noise and ran for 5+ years like that. My current Mazda doesn't even have an oil pressure gauge of any kind! But I do agree with the loose connector being the culprit here, and I also think snipping off the stock end and replacing it with a ring connector would solve your problem. Either that or buy a whole new part of the harness, it's under $30 from NPD.
 
6

66moneypit

Member
Dec 28, 2004
536
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Northern Va
Aug 1, 2006
#12
  • Aug 1, 2006
  • #12
I hadn't thought about buying a new harness. It's soooo random it's not even funny. It rarely happens but when it does it's unnerving. I will just cut it for now. It's an easy fix and if it works great. It only happens 2-3 times in the last 3000 miles. It could be my gauge as well it is suspect too because when it's running normal it barely gets about the (C). Not sure where the needle should point when it's working properly.
 
1

1966conv

New Member
Mar 5, 2004
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Aug 1, 2006
#13
  • Aug 1, 2006
  • #13
I've had the same thing happen twice on my 66, except it did it to all the gauges. Only lasted a couple seconds and was back to normal.

Never did figure out what caused it, haven't had it happen in a while now though.
 

dennis112

15 Year Member
May 15, 2005
1,561
36
79
Amish Wonderland of Central PA.
Aug 1, 2006
#14
  • Aug 1, 2006
  • #14
1966conv said:
I've had the same thing happen twice on my 66, except it did it to all the gauges. Only lasted a couple seconds and was back to normal.

Never did figure out what caused it, haven't had it happen in a while now though.
Click to expand...

More than likely the problem with yours is that the Voltage Regulator found on the back of your guage cluster had a hiccup or an issue with its ground. The one VR controls the fuel guage, temp guage, and the oil pressure guage. When one goes, usually all 3 guages quit working.
 
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