temp sensor diference LT1
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Burning Brakes
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From: Fitzwilliam New Hampshire
temp sensor diference LT1
temp sensor at water pump part#,temp sensor at right side head part#.Are these 2 different parts,or are they interchangeable?Replaceing water pump and want new sensor for fan control original is old and plastic brittle.1994 C4 LT1
Last edited by A Peter C4; Aug 9, 2016 at 09:48 PM.
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Since they are the same inside, many parts suppliers are only selling the 2-pin version. To use it in the head, you would have to change the pigtail (sometimes included) and ground one of the wires.
The 2-pin one normally goes in the water pump and the 1-pin version goes in the head.
The 2-pin one normally goes in the water pump and the 1-pin version goes in the head.
Last edited by GaryDoug; Aug 9, 2016 at 10:32 PM.
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***Seems GM# 15326386 is the newer GM to use as a reference for confirmation
"GD" is very mistaken!
Last edited by WVZR-1; Aug 10, 2016 at 01:08 AM.
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Nope. I have first hand experience with this. They are interchangeable except for the hardware config. Same resistance profile. Have measured them side by side in a heat chamber. LT1 gauge sensor has only one wire by the way, not 2 ;-)
Last edited by GaryDoug; Aug 9, 2016 at 11:01 PM.
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The later LT1 temp sender is actually 2-pin but used as a single and the 2nd pin I expect for preventing misuse as a different sender in another application where specs are way different.
Show me a part # where it tells you can be used for either function.
Last edited by WVZR-1; Aug 9, 2016 at 11:24 PM.
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Ok, here's the deal. I'm an EE that hangs out in a lot of LTx forums mostly to give electrical advise. One guy with a 94 LT1 Vette posted that his head temp sensor was broken, still worked, but the connector would not stay on because part of the plastic was missing. He ordered another sensor and it came with two pins and a pigtail with instructions that were a bit vague, something like "Universal application: one wire to ground-one wire to signal". He asked me if I knew how to use it. I did not but offered to test it for him since he lived only a few miles away. He arrived with both the new 2-pin sensor and the old "broken" 1-pin one. I have a heated environmental test chamber that goes easily to 250F, but does not cool, so we put them in the freezer and ran wires to both in order to read the resistances. Both tracked within 1% of each other down to 10 degrees F. Then we move to the "heat box" and ran the same tests up to 250F, same result but only 2% tracking at 250F. I did not know this would be the case, but it was and we were both pleased. Now the vague instructions made sense. I wish I had thought to get more info on the supplier of that particular sensor, but did not.
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Ok, here's the deal. I'm an EE that hangs out in a lot of LTx forums mostly to give electrical advise. One guy with a 94 LT1 Vette posted that his head temp sensor was broken, still worked, but the connector would not stay on because part of the plastic was missing. He ordered another sensor and it came with two pins and a pigtail with instructions that were a bit vague, something like "Universal application: one wire to ground-one wire to signal". He asked me if I knew how to use it. I did not but offered to test it for him since he lived only a few miles away. He arrived with both the new 2-pin sensor and the old "broken" 1-pin one. I have a heated environmental test chamber that goes easily to 250F, but does not cool, so we put them in the freezer and ran wires to both in order to read the resistances. Both tracked within 1% of each other down to 10 degrees F. Then we move to the "heat box" and ran the same tests up to 250F, same result but only 2% tracking at 250F. I did not know this would be the case, but it was and we were both pleased. Now the vague instructions made sense. I wish I had thought to get more info on the supplier of that particular sensor, but did not.
I wouldn't think that until you attempted "in real life" to use it as an ECT and confirmed operation with proper scanning devices you wouldn't suggest others just take what the're handed and it'll work. I'd be interested to see a part# that will do "BOTH" - I really doubt it's existence.
The only connector change I've seen in GM ECT (ECM/PCM) control was the change from the very early "button head" (knock sensor style) connector to the 2 pin that's still in use.
Last edited by WVZR-1; Aug 10, 2016 at 01:28 AM.
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There is only one factor here and that is the resistance. As long as the wattage is within the limits, the sensor will operate exactly the same regardless of the voltage applied (see Ohms law). My comment was directed at the question about the difference between the water pump sensor and the one in the head for the gauge. I am sure you would agree that the gauge sensor is the less important one and could accept the larger tolerance. In other forums I have, for years, suggested the use of the 2-wire sensor (with possibly tighter tolerances) for the gauge circuit and it has always worked for many, many users. However, I would never suggest using the 1-wire sensor for the pcm simply because it would be inaccurate by the design that precludes the use of the second wire for the reference without creating a ground-loop situation. I am sure you have noticed that some places like Rock Auto do not even offer a 1-pin sensor.
Last edited by GaryDoug; Aug 10, 2016 at 08:38 AM.
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I get the use of the ECM/PCM ECT for dash analog gauges but admittedly I've never substituted. The gauge has as wide a calibration tolerance as the sender so there's no need.
I ain't looking to argue or debate and to answer the OP's original question is use either of the OE#'s I supplied and he should get an appropriate sender/sensor calibrated for the ECM/PCM.
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They are all 2-pin sensors except for possibly the one not in stock.
Last edited by GaryDoug; Aug 10, 2016 at 09:38 AM.
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I don't understand why people "hope" instead of just trying it: Here is what RA shows when a simple search for "25037332" (the GM part number for the head sensor from a GM dealer web site) is made: http://www.rockauto.com/en/partsearc...og%2Fchevrolet
They are all 2-pin sensors except for possibly the one not in stock.
They are all 2-pin sensors except for possibly the one not in stock.
I ain't wishin, hopin or prayin - that's quite simply fact.
Here's the correct connector when used as a 1 - pin
https://www.amazon.com/ACDelco-PT728.../dp/B000C9SS4Y
I've never seen a connector that even implies that the center(larger) pin is actually a "common ground" BUT to function as a 1 pin "the sender" must so it could be maybe assumed that when you substitute a correctly terminated 2 wire it could function as a 2 wire device.
Last edited by WVZR-1; Aug 10, 2016 at 09:59 AM.
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No. This is the one a forum member recently ordered for his F-car: http://www.rockauto.com/en/moreinfo....=40504&jsn=474
It is the same one referenced in the search at RA for the head sensor.
It did NOT work for the sensor in the head (for the gauge) until he GROUNDED the second terminal. In his case, that was the specific reason for starting a forum topic. I told him to ground the unused pin, he did, and the gauge worked.
I am done with this topic, better things to do.
It is the same one referenced in the search at RA for the head sensor.
It did NOT work for the sensor in the head (for the gauge) until he GROUNDED the second terminal. In his case, that was the specific reason for starting a forum topic. I told him to ground the unused pin, he did, and the gauge worked.
I am done with this topic, better things to do.
Last edited by GaryDoug; Aug 10, 2016 at 10:03 AM.
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If I recall right from the service manual, for the analog sensor in the passenger side of engine you can pull the single wire pigtail off the sensor, and ground that wire out with key on.
If the analog gauge in the car pegs out on the dial the sensor is bad.
If the analog gauge does not move then you ground out that wire then gauge or wire is bad.
If the analog gauge in the car pegs out on the dial the sensor is bad.
If the analog gauge does not move then you ground out that wire then gauge or wire is bad.