The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1973 - 1987 Chevrolet & GMC Squarebody Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 09-27-2021, 01:22 PM   #1
ellisjay2
Registered User
 
Join Date: Feb 2014
Location: marietta ga
Posts: 147
Temp sensor/ gauge not reading....

Dropped another 350 in and my temp gauge isn't reading after I let engine run to normal temp feeling top radiator hose...I'm not sure if wiring is bad from being old or sensor itself has gone bad, I've forgotten how to test sensor with fluke meter, and all else fails what's the route to go and difficulty to run new wiring and sensors for gauges. I still have factory dash clusters and all other gauges are working.
Attached Images
 
__________________
: Eli540

86 gmc 2500 longbed Carb 5.7, rwd,
400 tranny.

Last edited by ellisjay2; 09-27-2021 at 04:48 PM.
ellisjay2 is offline   Reply With Quote
Old 09-27-2021, 02:23 PM   #2
mongocanfly
Post Whore

 
mongocanfly's Avatar
 
Join Date: May 2015
Location: Alabama
Posts: 14,670
Re: Temp sensor/ gauge not reading....

https://www.youtube.com/watch?v=puNKAW5Nurc
__________________
Mongo...aka Greg

RIP Dad
RIP Jesse

1981 C30 LQ9 NV4500..http://67-72chevytrucks.com/vboard/s...d.php?t=753598
Mongos AD- LS3 TR6060...http://67-72chevytrucks.com/vboard/s...34#post8522334
Columbus..the 1957 IH 4x4...http://67-72chevytrucks.com/vboard/s...63#post8082563
2023 Chevy Z71..daily driver
mongocanfly is offline   Reply With Quote
Old 09-27-2021, 07:35 PM   #3
Pontiac1976
Registered User
 
Pontiac1976's Avatar
 
Join Date: Oct 2015
Location: Ottawa, Ontario, Canada
Posts: 766
Re: Temp sensor/ gauge not reading....

I guessing the sender is the one in the pic. It looks rust I would clean it with Dremel Tools and small wire wheel on as Accessory. Maybe emery cloth if you do not have the tool. Then re-check the gage to see if working if not make sure the wiring is not broken has a good clean contact. Then do one check at a time till you find out where the problem is. But looking at how rusty it looks I would take it out clean it on a beach wire wheel.
__________________
1977 REG cab Long Bed with a 1984 Front Clip, 82 305 .60 over 9.0.1 flat top pistons, 4bbl, TH350, w/84 SS-intake & cam , w/ 1977 big block rad, 1975 gear box, 1984 master w/ metric fittings top & SAE fitting @ portion block, 1975 3.42 gear open diff. Duel 77-87 Factory air cleaner, duel inlet from rad support . Down sized 9' to new 8' Steel flat bed
Was a 77 454 w/308 gear. Taken out 550 lbs. up front with motor clip change.
Pontiac1976 is offline   Reply With Quote
Old 10-03-2021, 07:34 AM   #4
ellisjay2
Registered User
 
Join Date: Feb 2014
Location: marietta ga
Posts: 147
Re: Temp sensor/ gauge not reading....

Gauge still not reading......replaced temp sensor, did peg check, gauge will kick all the way to hot when pegged out, I pegged it out running jumper wire from connector to block. That indicates wire and gauge are working right??? Changed sensor, ran truck till thermostat opened felt top hose hot, and gauge still stayed on cold. Not making sense. Only other thing I could think is the adapter bushing inside the block the sensor goes in is corroded. Any other suggestions !!!?????!????
__________________
: Eli540

86 gmc 2500 longbed Carb 5.7, rwd,
400 tranny.
ellisjay2 is offline   Reply With Quote
Old 10-03-2021, 09:18 AM   #5
Dead Parrot
Registered User
 
Join Date: Aug 2012
Location: Oklahoma City, OK
Posts: 2,611
Re: Temp sensor/ gauge not reading....

Grounding the sender wire from the gauge should give a full scale reading. That part sounds like it is working.

Make sure the sender is a gauge sender and not an idiot light sender.
Senders from different year ranges have different temp/resistance curves. Many aftermarket senders don't match the OEM versions. Not unheard of for the parts store to sell an idiot light sender as a gauge sender. They often look similar.

If you have an Ohm meter, check the resistance of the sender cold. Should be high but not infinite. Depending on sender, somewhere between 2500 and 900. Then check hot. Should be much lower. Between 100 and 40, IIRC.

This issue is fairly common. Several threads on the subject.
Dead Parrot is offline   Reply With Quote
Old 10-03-2021, 10:09 AM   #6
Corts60
Just here to tinker
 
Corts60's Avatar
 
Join Date: Jun 2008
Location: Holland, MI
Posts: 3,697
Re: Temp sensor/ gauge not reading....

X2. You may have installed a temp switch for an idiot light and not an actual sender. Boil it in a pan and if it does not move through a range of resistance as it heats up, then it is probably a switch. You’ll know because you’ll get an o/l reading until the switch closes and then you’ll get resistance all of a sudden.
Corts60 is offline   Reply With Quote
Old 10-05-2021, 07:51 PM   #7
ellisjay2
Registered User
 
Join Date: Feb 2014
Location: marietta ga
Posts: 147
Re: Temp sensor/ gauge not reading....

Anybody have the own part number for the correct temp sender to gauge??
__________________
: Eli540

86 gmc 2500 longbed Carb 5.7, rwd,
400 tranny.
ellisjay2 is offline   Reply With Quote
Old 10-05-2021, 08:43 PM   #8
ellisjay2
Registered User
 
Join Date: Feb 2014
Location: marietta ga
Posts: 147
Re: Temp sensor/ gauge not reading....

I have a fluke meter, but how do I connect both prongs to sensor since its one prong, then submerge in water???
__________________
: Eli540

86 gmc 2500 longbed Carb 5.7, rwd,
400 tranny.
ellisjay2 is offline   Reply With Quote
Old 10-11-2021, 03:14 PM   #9
ellisjay2
Registered User
 
Join Date: Feb 2014
Location: marietta ga
Posts: 147
Re: Temp sensor/ gauge not reading....

Problem solved, oreillys gave me the sender for the light the first time, which looked almost identical, when getting the other one, you can tell difference in shape depth, one of the techs caught it. Temp jumps up between C and middle range....but now I have to find oem metal fan, and shroud....not going the electric route....
__________________
: Eli540

86 gmc 2500 longbed Carb 5.7, rwd,
400 tranny.
ellisjay2 is offline   Reply With Quote
Reply

Bookmarks


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 10:36 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com