Question about 1998 GMC Sonoma

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The factory coolant temp sensor had 3 wires an a aftermarket on as 2 how do i hook it up.

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You don't. Either you have not pulled the correct sensor or your replacement sensor is wrong. Three wire sensors have a constant reference voltage, signal return and ground. 2 wire have no constant reference voltage.

Posted on Oct 14, 2013

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    _-__-___-_ Oct 14, 2013

    but he never said which of the 3 was bad, ECT? but on this car its the wrong sensor for all. there are many 3wire sensor, the jon type and others, can prove that. and it dont matter, its the wrong sensor, send it back. this time tell them what engine. and year.


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You bought the wrong sensor
there car 3 types used on many engines.
and there are many GM engine options, every year.
so did you buy it in a store, o r online,?

most online buyer need to know what they are ordering.
(yes, buying parts can be a horror,for anyone.)
that is because online is not indexed by VIN, (dolts)
Some stores, list 2 of 5 engines and stupidly assume there are just 2. this really ges my goat.... end rant.
in a real store they ask for VIN, on GM there is a RPO sticker
in the glove box.and has engine code right there. (a build list)
some times the VIN gets it right the engine code there,, but not always.

the 3 sender are. (circa 98) ECT, dash guage, and A/C over heat.
post the engine size,.vin # or rpo sticker photo.

when you see the 3 wire, that usually means the sensor covers
2 temp senders in one. and is wrong for you.
try using smp cat. 2.4l or 4.3L it shows.
i looked there and both engines are 2 pins. 1998
tell me brand of sensor and box pn, and ill tell you every engine it fits
or go to rockauto, and do same.

i looked and not one 3pin ,just 2 and the 1pin gauge sender
if you have different engine. than the 2 listed above. all bets off.

Posted on Oct 14, 2013


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