temperature gauge

[Robin7TFour]

hello, i am having problems getting my temp gauge to work. i have power to the gauge itself. i have continuity to the sending unit( i can go to ground and gauge will work). i have changed the sending unit twice. i used off the shelf ,pep boys, parts.
i have seen ads that claim there are different sending units for earlier years. i am lost:confused

i appreciate any and all suggestions


robin

 

[JohnZ]

What does the gauge do? What does it do when you ground the terminal that connects to the sending unit? When you ground the wire, the gauge should go to full hot, and when you disconnect it, the gauge should go to full cold.

 

[Robin7TFour]

john, my gauge goes to about 90% full hot. then full cold when un-grounded. that's why i am confused. so far non of the sending units i have tried have worked, at all.
i cleaned the threads on the block and on the sending unit. now i am thinking of trying a sending unit that is suppose to work on 74 and earlier gauges.


'lost in space'



robin :duh :duh

 

[JohnZ]

They may be selling you the wrong sending unit. There are two kinds - one (for gauges) that has an internal variable resistor, and one (for idiot lights) that just has an on-off switch inside it. If you use the idiot-light type with a gauge, the gauge will go immediately to full cold and stay there - it won't move unless the engine overheats, at which point it will go immediately to full hot.

Try a Wells TU-5 (AutoZone, $5.00) - they're calibrated more closely than any of the other parts store replacements.

 

[Robin7TFour]

john. thank you for the info. btw, i enjoyed your article in corvette enthusiast magazine(cooling systems) . very easy to follow your thoughts..


robin

 

[Robin7TFour]

greetings, once again i attempted to get my temp gauge to work. i tried ;1) adding another ground from the engine to frame
2) adding a temp ground to the sender itself
3) adding an extra ground on the back of the
gauge cluster
4) swapping with a gauge from a 76
5) removing the wire at sender and grounding direct.. then the gauge read full hot
6) tried the tu-5 wells sending unit.

i am really befuddled,bamboozled,and downright confused.
what am i missing. could the gauge be hooked up wrong? or the insulators on the gauge in the wrong placement? i just don't know.


robin

 

[JOliver]

Yes
After trying all that I'd say you have an insulator thats not there or maybe in the incorrect place...grounding the gauge to the case.
There are three terminals on that gauge...one in the middle should be your ground(it touches the case in the 9 o clock postion) The 12 oclock and the 6 oclock should be touching the resistor...the 3 oclock should have and insulator under it and should NOT be touching the case...you also might have a bad gauge it happens from time to time..its an air core movement and they corrode internally and develope problems from time to time.


Jason
VetteInstruments@aol.com

 

[vmrod]

Do you have teflon tape on the threads of the temperature sending unit? If so, that may be preventing it from making ground with the engine block.

-Vic

 

[Robin7TFour]

vic, no teflon tape. i learned that when i first got involved in this car. after that i made sure it was all clean.


thanks for the response.


robin

 

[Robin7TFour]

greetings, today i checked the sender after the motor warmed up. the resistance appears to be good. so i am back to the gauge. can someone look in the 74 assembly manual and possibly print out the proper gauge installation? i want to see if i have the insulators in the correct positions.

thanks for the help(in advance)

robin