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So the tab broke off on the coolant sensor on the passenger side of the head. Is there a difference between that and a sensor for say a 1970 chevelle or something? They look identical but at autozone they referenced "with light" or "without light". I'm wondering if the with light is one that simply grounds itself out when it reaches say 240* or something while the one that is " without light" is the one that actually sends a voltage for exact temperatures?
One was $17 and other was $11... Was thinking of making the other side a tab sensor also instead of the prong style....
If the engine is an LT1, that sender/sensor (one wire) is for the analog dash display. As indicated, some stores have it listed as a sender. If not an LT1, no help here.
There are two coolant sensors. The other one for the PCM is in the LT1 water pump.
You could do like I do...bring your DVM to the store and check ohms. The correct sensor will have some ohm value, not zero or infinity.
All coolant temperature sensors are basically the same. They change resistance with temperature.
If you look in the FSM you will find variations on this chart in multiple places:
Those are maybe for ECT sender for ECM? There's of course similarity to values but the tolerances are a "wide stretch" on TSU for cluster.
From an '87 FSM for the cluster gauge check:
If you're concerned about the functionality of the sender in comparison to the cluster component you need to check both.
Take the sender/switch you're wanting to use and get water to temp you're most concerned with or check at various temperatures and then supply the cluster with similar values to compare cluster to sender.
A Wells sender @ 1430 OHMS +/- 20% is 100° and @ 152 OHMS +/- 10% is 220°
OP - most after-market are certainly "very generic" - The Wells I mentioned is considered a replacement for 7 OE part numbers. Most later '79+ are done with similar reference, your mention of '70 Chevelle might be a stretch but if you compared values against cluster you could confirm.
So the sensor from the water pump would be the digital readout on the dash, while the sensor on the side of the engine is for the analog gauge that is usually inaccurate? On my '93 the analog gauge is 70-80 degrees lower. Can a resister be added to the one side of the wire to raise the analog readout to be near the digital readout?
If that can be done, can it also be done for the outside temp sensor which reads 40-45 degrees hotter than actual temperature?
So the sensor from the water pump would be the digital readout on the dash, while the sensor on the side of the engine is for the analog gauge that is usually inaccurate? On my '93 the analog gauge is 70-80 degrees lower. Can a resister be added to the one side of the wire to raise the analog readout to be near the digital readout?
If that can be done, can it also be done for the outside temp sensor which reads 40-45 degrees hotter than actual temperature?
I don't believe that the resistor could be added to correct at anything other than one specific value. It's a non-linear (I believe that's correct) and the % +/- tolerance hot to cold isn't controlled but varies widely. The analog is done on most using a single wire. A later cluster (your '93) only has two values to confirm on the analog, one full cold, and the other full hot.
I would think you could confirm the readings providing known values to the cluster and checking the engine component like I mentioned.
Full cold is 1400Ω maybe and full hot 55Ω.
Maybe the OAT just needs replaced or diagnosed first.