Aftermarket Water Temperature Gauge Sending Unit

[Blacksheep Josh]

Okay, I'm having a small issue trying to understand this.

I have an aftermarket water temperature gauge, and everything in it makes sense for the installation except for the sending unit. I understand you have to install it so it'll have contact with the coolant and you can figure out how hot/cold it's running. For this I'll probably have to drill a hole, install it, and get it nice and sealed.

Now for the wiring, there are three wires coming out of the gauge, Black for ground, red for ignition activated/power, and green for the temperature hookup. It's saying to hook it to the sending unit, but there's no obvious installation area on the unit. I'm wondering if for this do you solder it or crimp it around? I'm guessing the brass unit absorbs the heat, and then passes it to the wire or something? Kind of like computer heat sinks?

Any help would be great.

Edit: With the same unit, would it be possible to install a unit into the transmission lines, and then a switch to flip between the two? Kind of like the switch in F-150's for dual tanks?

 

[Maniak]

When we installed our sending unit we installed it in the heater hose that comes off the upper intake.. That way I know the water temp of the motor, even if the thermostat isn't open.

As for the connectors...

The gauge itself is connected like you said, red to switched 12V, black to ground and the green goes from the gauge to the sending unit...

The sending unit will have some kind of a connector on it.. Some have what looks like a little screw on the top, others have what looks like a little screw with a flat piece at the top of the screw..

If its a screw, just use a "butt connector" if you don't have the correct type of connector.. a butt connector crimped on the wire and then pushed on the sending unit will work. (our oil pressure sending unit is connected like that).

If the sending unit has the little flat piece on the top of the screw looking thin you put in a 1/4" spade connector on the wire and the spade connector just connects to the little flat piece..

One thing to remember, if your sending unit is a single wire (sounds like yours is) you need to make sure it is grounded.

Here is a pic of a sending unit with the "flat" thing on top.. And you can see how we ran a wire to it to ground it. We "made" the hose fitting so we could put the sending unit where we did. This was on a vehicle that got an electric fan. On our X, I used a store bought host fitting but I didn't have the ground wire issue since the sending unit I used was a 2 wire, meaning it has its own ground.

Here is a store bought fitting.. Its $35ish from egauges.com (where I buy my gauges etc)..

~Mark

 

[Blacksheep Josh]

Thanks for the awesome response.

My only question now though, is how do you ground it? It looks like in your picture, you just connected a wire to the piece of metal you installed the sending unit (not the actual unit itself, but the adapter it's plugged/screwed into) to the body. Is that how you did it?

I'm not installing mine yet, probably be a few weeks, I'm just trying to work out all the kinks before I start on it.

 

[Maniak]

My only question now though, is how do you ground it? It looks like in your picture, you just connected a wire to the piece of metal you installed the sending unit (not the actual unit itself, but the adapter it's plugged/screwed into) to the body. Is that how you did it?

Yup, thats all we had to do.. As long as the body of the sending unit is touching the grounded metal the sending unit is grounded. Thats why many sending units say not to use teflon tape. If you use too much the threads won't cut through the tape and you won't ground the sending unit. We used teflon paste to seal the threads instead of teflon tape.

That store bought hose adapter has a screw hole in it where you can connect a ground wire to it instead of doing it the way we had to with our homeade hose adapter.

~Mark

 

[rookieshooter]

For more of a sanitary look on the ground wire to sensor, try this trick that I used on my tranny temp. sensor that is installed in one of the lines that go to remote cooler. Just get one of these round electrical crimp on eyelet ends at your auto store. This one is a 3/8" dia. Just screw it onto the sensor and then screw sensor into whatever fitting it goes into. The wire that goes to temp. gauge is connected to top of sensor.

Also I'm a big fan of liquid electrical tape on all my connections. That's the black stuff you see on the connection. NAPPA sells it.

 

[Blacksheep Josh]

Appreciate it y'all.

What about my other question? Think I could run a switch, so I could go back and forth between transmission temp and water temp? I mean, all I'd have to do is run another sending unit and wire.

 

[aldive]

With the same unit, would it be possible to install a unit into the transmission lines, and then a switch to flip between the two? Kind of like the switch in F-150's for dual tanks?

I did that with an oil temperature gauge and a ATF temperature gauge.

Take a look at http://www.explorerforum.com/forums/showthread.php?t=141191&highlight=oil+temperature

 

[Blacksheep Josh]

I did that with an oil temperature gauge and a ATF temperature gauge.

Take a look at http://www.explorerforum.com/forums/showthread.php?t=141191&highlight=oil+temperature

Thanks, I totally forgot about that. I knew I'd seen it done somewhere