So I finally managed to get my laptop hooked up to my car, and it is throwing code 15, (open coolant temp sensor) and I went to try and replace it today. Problem is this isn't the stock connector and I can't find out any information on what or where the sensor came from. I would rather not have to splice on a new connector right now. Does anyone have any idea where this came from? The only thing on it is "HS125CM 12V 0919". Thanks!

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1985 GT 2.8 MT
1988 GT 4.9 AT

That's the gauge sender.
The coolant temp sensor is in the intake manifold, right next to the thermostat housing.

So did you wire the engine or did someone else wire the engine?

The CTS sensor wire (yellow) and CTS ground/return wire (Black or Black/Pink) have to run to the actual CTS sensor. But don't throw this connector or sensor out since you still need it to make your gauge/light run.

If the yellow wire and black wire run to this they need to be moved.

That is a stock V6 Coolant Sensor - the one that goes in the head of the V6. It was installed in the 4.9. You can get a new one at most auto parts stores.

So NJD85GT

The correct CTS is going to look like this:


(the one on the left)

OR


(Three pin CTS) - The yellow and black wires go to the two outside pins of the sensor. The center pin can be used to control the temp gauge.

Your sensor - the one pictured - can also be used to control the temp gauge and temp light.
Temp gauge and temp light wires are usually Lt. Green, and Green/Yellow. Of course they may be any color.

BTW - read this post re Injection Technologies 4.9 engine harness temp gauge problem
https://www.fiero.nl/forum/F...2/HTML/091785-2.html

Ok, come to think of it the guage in the dash worked. I think they wired it so the CTS sensor goes to the dash and the head temp switch goes to the ECM, from reading the other thread. I'll see how I want to re-wire it.

Thanks again!

quote Originally posted by NJD85GT: Ok, come to think of it the guage in the dash worked. I think they wired it so the CTS sensor goes to the dash and the head temp switch goes to the ECM, from reading the other thread. I'll see how I want to re-wire it. Thanks again!

If the gauge in the dash worked you may have a problem. Problem being the PCM absolutely needs a temp signal. This is why most switch to the 3 wire sender. It feeds both the PCM and gauge. Double check that you have a temp signal getting to PCM pin E16. This is the green connector and most likely will be marked as C16 on the connector.

The head temp switch is really just an add on. Not necissary but may help if you don't watch your temp gauge a bunch or don't trust it. Some like having a warning light also.

EDIT: Woo hoo! My 4000th post!

[This message has been edited by Fieroseverywhere (edited 08-02-2011).]

quote Originally posted by Fieroseverywhere: If the gauge in the dash worked you may have a problem. Problem being the PCM absolutely needs a temp signal. This is why most switch to the 3 wire sender. It feeds both the PCM and gauge. Double check that you have a temp signal getting to PCM pin E16. This is the green connector and most likely will be marked as C16 on the connector. The head temp switch is really just an add on. Not necissary but may help if you don't watch your temp gauge a bunch or don't trust it. Some like having a warning light also. EDIT: Woo hoo! My 4000th post!

congrtulations! i just gave you a thumbs up