Are the coolant temp sensors the same?

[obstuba916]

Hi everyone this is my first post here. I always read on this site and I'm so happy it exists.

So, what is the difference between the sensor near the thermostat vs the one on drivers side head? I know the thermostat one is for the ecu and the head is for the dash but I cannot find any info on sensors for sale that differentiate locations. or are they the same sensor? I’ve seen people say that the one on the head is one prong vs two prong on the thermostat and it's different for different years and engines.

I have a 1994 Silverado with the 5.7 tbi and I’m having issues with the gauge reading proper temperature. I know it gets to operating temp because I test it almost every time I turn it off with an infrared thermometer. 170-199.

Recently I replaced the radiator, water pump, and fan clutch so I don't know if any of that would cause the guage to be lazy.

 

[RichLo]

They are not the same sensor.

The easiest way to tell when getting a replacement from the parts store is the one by the T-Stat for the ECM is 2-pins and the one on the head for the gauge only has 1-pin inside the plug housing.

I tried looking up part numbers for these but nothing seems standardized. Rock Auto seems to have a few that are very specific with their pictures and descriptions.

 

[someotherguy]

Yep, like RichLo said definitely not the same. 1994 seemed to be the year model that GMT400's went to the temp sender style on the head that has an oval socket that looks like the 2-pin connector for the temp sensor on the intake, but only has 1 pin populated. Looks like this:

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Older models had a round pin that a connector slides over. I've seen some senders come with an adapter harness, too.

Richard

 

[dhs4125]

piggy-backing on this after reading a few other threads on Temp sensors. Hoping to confirm what I think Im reading... '95 K2500 Suburban 7.4 TBI. Found this on the passenger side. Sounds like it's for the Aux Fan maybe. The thing was hanging there w/spring dangling out and doesn't seem to want to stay put. Anyone game for helping ID this guy?

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[someotherguy]

piggy-backing on this after reading a few other threads on Temp sensors. Hoping to confirm what I think Im reading... '95 K2500 Suburban 7.4 TBI. Found this on the passenger side. Sounds like it's for the Aux Fan maybe. The thing was hanging there w/spring dangling out and doesn't seem to want to stay put. Anyone game for helping ID this guy?

You must be registered for see images attach

Definitely the aux fan switch.

Richard

 

[dhs4125]

Thanks R. When I see the head rest profile pic, answers are Truly Awesome

 

[Luke_P]

For my 1989 K3500 with the 7.4, I was not able to find a suitable replacement switch to screw into the head. I ended up taking the relay switch wire into the cab so I can turn the fan on when I want.
For me, that means when I want cold ac in traffic and when plowing or climbing hills.

 

[Keeper]

Hi everyone this is my first post here. I always read on this site and I'm so happy it exists.

So, what is the difference between the sensor near the thermostat vs the one on drivers side head? I know the thermostat one is for the ecu and the head is for the dash but I cannot find any info on sensors for sale that differentiate locations. or are they the same sensor? I’ve seen people say that the one on the head is one prong vs two prong on the thermostat and it's different for different years and engines.

I have a 1994 Silverado with the 5.7 tbi and I’m having issues with the gauge reading proper temperature. I know it gets to operating temp because I test it almost every time I turn it off with an infrared thermometer. 170-199.

Recently I replaced the radiator, water pump, and fan clutch so I don't know if any of that would cause the guage to be lazy.

When looking up the part, the one in the head is called a sender, not a sensor. Sensors go to computer, senders go to gauges. Rock Auto mixes them together under the same heading (Cooling System - Temperature Sender/Sensor), but each part is clearly identified as either a sensor or sender. This link is for a sender.

More Information for ULTRA-POWER 5S1018

 

[Road Trip]

piggy-backing on this after reading a few other threads on Temp sensors. Hoping to confirm what I think Im reading... '95 K2500 Suburban 7.4 TBI. Found this on the passenger side. Sounds like it's for the Aux Fan maybe. The thing was hanging there w/spring dangling out and doesn't seem to want to stay put. Anyone game for helping ID this guy

After a bit of poking around, I followed a series of part numbers > dusty databases > cross-references, and back-doored into this current listing:

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(Link to this page: Aux electric engine coolant switch)


NOTE: The part number I initially started out with for the passenger side Aux Engine Coolant Fan switch was the AC Delco #15-5547.

This part must have been discontinued, for it was mostly out of stock, and for the few remaining ones the asking price
was in the $199 range? Eff me. However, thanks to some cross-reference numbers listed, I followed the bread crumbs,
hit a few dead ends before the trail warmed up and I skipped like a like a rock from reddit > ebay > RockAuto > GM parts giant.

****

The moral of the story? As our sturdy yet aging 22-36 year old machines continue to rack up the miles, it pays
for all of us to watch over our machines, and actually future-proof a bit and buy a few of these showstopper parts
*before* we need them.

For it's easy when in a hurry to find the obsolete part number and mistakenly pay the long dollar in order to get your
DD/weekend hauler/toy tower back up and running asap...instead of spending the time you don't have to find the
current listing buried in an unexpected corner of RockAuto or be extra savvy like the @GoToGuy and know about
GMPartsGiant.com.

For what it's worth I attached some of the pages that I bounced through in order to track down the GM part above.

Hope this helps those owners of a big block GMT400 with these Aux electric cooling fans setups.
After going through this I'll be adding one of these to my prepper cache of Press on Regardless bits. :0)

Keep on truckin' --

 

[obstuba916]

Yep, like RichLo said definitely not the same. 1994 seemed to be the year model that GMT400's went to the temp sender style on the head that has an oval socket that looks like the 2-pin connector for the temp sensor on the intake, but only has 1 pin populated. Looks like this:

You must be registered for see images attach

Older models had a round pin that a connector slides over. I've seen some senders come with an adapter harness, too.

Richard

So, I replaced that sensor and my guage still does not show accurate temp. I didn't laser any temps today but the most it read was 140. I typically read at 170-190