What sensor is this...

[KlingonFiero]

Hi All!

Will try to post a pic later, if needed, but hopefully someone just knows what I am asking

I have a a set of heads off of a 92 Regal (3.1 ), there is a weird looking, at least to me, sensor on one of them.

It looks like a real small CTS, but instead of the normal plug, it has a 6 inch pigtail with two wires coming out of it, a blue wire and a black wire.

Does this ring any bells???

TIA!
-Don

[geoffinbc]

Electric fan switch possibly??

[KlingonFiero]

Could posibly be...

I forgot to mention that the Blue and Black wires terminate in a two-pin weatherpack connector. The two wires coming out of the other side of the plug are both green w/white stripe ???

Actually, I do not think it is a fan switch directly- the ECM controls the fan...

I have found only two CTS units. One I know send two signals to the dash (one for the guage and one for the idiot light)

Maybe the sending unit with the pigtail is for the ECM? The blue is the signal and the black is the ground???

Any help is greatly appreciated! I am dying to get this car on the ROAD!!!

[3100 MPFI]

The only sensor I know of attached to a head is for a coolant temp sensor for the CLUSTER, but it is only a 1 wire (green).

Just like yours, it is about a 6 inch pigtail, but still, only one wire.

If you can get a pic of it, that would help.

[19Cutlass94]

only sensor I know of in the heads was the coolant temp for the cluster as mentioned above. but it was a single green wire. I cant remember if the newer style was a 2 or 3 wire, but its possible that maybe someone put the wrong yr sensor in?

[Guest]

The "blue" wire should be green, probably just looks blue due to oil and heat getting at it.

This is a dual connection CTS. I know one side is for a gauge, and I believe the other side is a switch, possibly for a light. I had one in my truck for a while and only used the black wire, as that ran my gauge, the other one never seemed to change state, whihc is why I believe it was a coolant over heat light sender. I know I have also read information that would confirm this but I don't recall where.

[KlingonFiero]

I will get a pic taken and uploaded later today.

If both CTS on the engine are for the guage/light in the dash - that is going to suck. I am pretty sure that the ECM is going to need a CTS signal...

[19Cutlass94]

The ECM uses the signal from the sensor in the LIM by the t-stat.

[86euro]

The "blue" wire should be green, probably just looks blue due to oil and heat getting at it.

This is a dual connection CTS. I know one side is for a gauge, and I believe the other side is a switch, possibly for a light. I had one in my truck for a while and only used the black wire, as that ran my gauge, the other one never seemed to change state, whihc is why I believe it was a coolant over heat light sender. I know I have also read information that would confirm this but I don't recall where.

Exactly, it runs a gauge and a temp light. I've had several Celebrities with the same setup, only difference was, the sender had a pigtail with green/white and green wires to match the vehicle harness.
The sensor in question is likely an aftermarket replacement with different colored wires. They are known to fail, causing the temp light to gradually come on as the engine warms up.

[3100 MPFI]

The only thing I am wondering about is that the engine was a from a 92 regal, so it would have to be something aftermarket if it was the temp sensor. Every regal I have seen had the one wire. The previous owner might have added something.

I will see if I can get a pic on my STE of the sensor and see if it is the one you are talking about.

[Guest]

Thank you, I knew it was in one line of cars but wasn't coming to me earlier. Celebrity was where mine came from.

[KlingonFiero]

Hopefully the pics come through...

The first one should be of the sensor in question - the blue wire is definitely blue...

The second one os of the sensor in the LIM - on the original 2.8 in the car (a Fiero) this sensor was for the dashboard only (gauge/light).

On the original 2.8 engine, the ECM CTS was a single wire unit.

I am having a lot of fun figuring out all of this stuff without a real manual - of course, I have about 5 different cars frankensteined into my Fiero, so a manual wouldn't be all that much help...

Thanks!!!

[3100 MPFI]

That first one is deffinantly the coolant temp sensor for the GAUGE. I have never seen one with 2 wires before. Normal stock is 1 wire that is either GREEN, or PURPLE.

Hard to tell from the second pic, but I am going to guess that it is near the thermostat area? That looks like the coolant temp sensor for the ECM. which is normally 2 wires.

If you can get a picture of even both of them pulled further back, I can confirm this.

On the first pic, the sensor lookes like it is next to a head bolt, so that is how I figure it is the coolant temp sensor. I still need to get down there and take a pic of the one on my STE for you.

Just so you know, you can get a sensor from a 1996~ish 3100 car. It is a 3 wire one that uses a connector like the TPS. I used that one on my STE becasue my single wire one was bad. It will screw right in, and I only had to run 1 wire and solder the other 3. Might want to consider doing that. I will try to get a pic of that as well.

[KlingonFiero]

That first one is deffinantly the coolant temp sensor for the GAUGE. I have never seen one with 2 wires before. Normal stock is 1 wire that is either GREEN, or PURPLE.

Hard to tell from the second pic, but I am going to guess that it is near the thermostat area? That looks like the coolant temp sensor for the ECM. which is normally 2 wires.

If you can get a picture of even both of them pulled further back, I can confirm this.

I can try to get another pic today. However. I know for certain that the second pic (the CTS with just the male plug on it) is for the gauge/idiot light.

I have already tested it in the oven

I didn't want to toss the one with the wiring pigtail in the oven, for fear of melting the insulation.

Just so you know, you can get a sensor from a 1996~ish 3100 car. It is a 3 wire one that uses a connector like the TPS. I used that one on my STE becasue my single wire one was bad. It will screw right in, and I only had to run 1 wire and solder the other 3. Might want to consider doing that. I will try to get a pic of that as well.

Great Idea! A pic would be excellent.

---------------------------------------

It looks like that due to all my mixing and matching of parts, I have two sending units that are for the same thing - i.e.: the gauge/idiot light.

If I can find one of the 3100 3-wire CTS - that would be great, I really like as few wires as possible!

[3100 MPFI]

ask and ye shall receive.

First of all, my cars are all toghther, and my spare sensor is in storage. I should be able to get the pic of the sensor out of the car tomorrow.

In the Regal, the sensor on the rear head is for the gauge/idiot light, and the sensor on the lower manifold are for the ECM/cooling fans.

Here is a pic of the HEAD sensor in my 1990 STE. The car is all together, so I can't really get a good pic, but you can make it out. I cut the pigtail off of it seeing that I am using the 3 wire sensor that goes into the lower intake manifold.




And here is the ECM sensor on the 1990 3.1 I have the 3 wire sensor in there, and it screwed right into the stock location for the 2 wire.




And lastly, this is my 3100 rear head, but if you look at the spot where the red X is, that is where the GAUGES/IDIOT light sensor is screwd in, My 3100 is out of the car and just sitting there, so it was easy to get a pic. When I go to storage tomorrow, I will see if I still have one of my bad 3.1 heads, and get a better pic.