Water temp gauge wiring ?'s

I bought an automotive type water temp gauge and have a few questions about the wiring. If you go to ulmerracing.com and look at his directions for the wiring of the gauge he sells, he says you just need to splice into a blue/white wire since blue/white is a keyed power source. Therefore the gauge will only go on when the key is turned on.


With my gauge there are four wires, I now what to do with two of them for sure. The green wire connects to the water temp sensor, the black goes to ground. And then there is still a red and yellow wire. The red goes to 12V+ ignition switch and yellow goes to battery(+) according the directions.


So do I have to hook the yellow directly to the battery and the red 12V+ ignition switch to the blue/white wire like ulmer racing says?

Or can I just hook up the red 12V+ wire to the blue white wire on my sled and get power that way and not worry about the yellow battery wire?

Do I need to hook up the yellow battery wire directly to the battery or can I splice another wire somewhere? How would a person without a battery on the sled get this gauge to power up?



Any help would be greatly appreciated.

Tom,
What gauge do you have? Make and Model will help.

It is a prosport gauge digital water temp gauge going on a 06 Apex. Any other questions let me know.

Attached is a picture of the wiring instructions.

Ok makes sense now. This is a little different then my cyberdyne gauge.

Yellow is your power wire. Red is a switch wire.
So I would take these steps.
1. Mount the gauge
2. Find the best routes to the battery, sender, ground and blue/white wire. Layout the wire for appropriate lengths
3. Hook up the Green wire to the sender, black wire to ground and red wire to switch (blue/white).
4. Hook up yellow last, you could put a small 2amp fuse in the yellow wire just in case.
5. Turn your key on and see if your gauge turns on, turn your key off and see if it turns off.

Looking at Ulmers instructions he uses the blue/white wire for both switch and power. This means you could run the yellow and red together to a blue/white wire. BUT he might do it that way because his gauge uses such a small amount of power.

I would follow my 1-5 steps unless somebody else can comment on how much power you can get from a blue/white wire.

Remember soder is your friend!

The blue/white wire only has power when the engine is running (it is the headlight circuit). If you want the gauge to turn on just by flipping the switch (but not starting the engine) use a red/white wire.

I only want the guage on when the engine is running.

Allen, do you know if I can run both the yellow battery wire and the red 12V+ wire to the same blue/white wire on the sled? Will this both power the gauge and tell it when to turn off and on.


I am afraid of hooking up a wire directly to the battery for fear it will drain the battery over time.


Thanks for the reply's both Luke and Allen, I appreciate it.

The gauge must have a relay built into it or into the wire harness that comes with it. You put a constant 12 volts to your yellow wire and this puts power to your relay. The relay is normally open circuit. Then you put the blue/white wire to your red wire and when the blue/white goes to power it closes the relay and allows power to go to the gauge. It should not drain your battery what so ever.

Option 1 = battery always has power to relay but blue/white wire turns the relay on when engine starts.
Red wire = blue/white

Yellow wire = + battery

You could also hook your yellow wire to the red/white in the harness and this would not allow it to drain your battery or get any power until you turn the key on.

Option 2 = red/white wire turns power on to the relay only when the key is turned on and blue/white wire turns on gauge when engine is running.
Red wire = blue/white

Yellow wire = red/white

Thank you very much. I greatly appreciate it.

Will probably be a few days before I install this thing. Will update this thread once it is installed.

Were you able to get it wired?
Post a picture if you would please.

Yes I did get it wired up. I used option 2 from srxspec above. I used the red/white wire for the main power, and the blue/white wire for the 12V+ accessory wire. I did get a few pictures as I did it, not that great of ones. I tapped into the wires near the fuse box. And I just took the bolt that holds part of the oil tank onto the frame and stuck my ground under it.

This is on a Apex

tkuss - sent you a PM. Looking for where you purchased and what model the gauge is found is.

Thanks in-advance.

pm'd ya back.

Here is a link to the gauge I got.
http://prosportgauges.com/Digital-water-temperature-gauge-1.aspx


I also got the hose splicer for the temp sensor there as well. The one a got was a mm or 2 to big( I think I got a 28mm and the hose is 26mm) But it worked fine, just went on a bit tight.

Also I got the gauge pod from there as well. But was a real cheap one.

Also when I bought mine, there was a coupon code "crooked" I believe which saved another 10% of the order.

Thanks TKuss - Looking forward to getting one ordered up.

tkuss, I think you did the right thing not to hook up your gage to the battery directly. I did tie it directly to the + battery post and yesterday, after the sled sitting for a few weeks, I tried to start it and it was no go. I do think the gage is sucking power from the battery, even when off. Guess I'll have to rewire mine.