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Prosport Gauge Testing: Where's the orange wire go?


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So, I'm playing around under the dash (2005 LGT) with the fuse panel and some Prosport gauges. I've seen several threads about how to wire gauges and I still don't have this quite right.


I will be running gauges on the left of the driver and as such, I feel the closest easiest (not to mention cleanest) method is to run them directly off the fuse panel with some fuse taps. Therefore, I'm not particularly interested in using a vampire tap near the cigarette lighter or some such other nonsense that doesn't make sense with this setup.


I have see a few mentions that say not to use more than 10 amps in the fuse taps and the ones I have even say 2 - 10 amps on the package. So, while I have seen a few options on where to place things, I'm trying to also keep the fuses that I tap as well as the fuses I use in the tap are all under 10A.


Again these are Prosport Halo gauges that have a


- red (constant power)

- white (accessory power)

- orange (powered when heads and/or tails are on)

- black (ground)


wiring harness.


I have the ground hooked up to the bolt holding the hood release lever up under the dash.


The options I have found for the red wire include:


#7 Unit +B (15A)

#10 D-Op +B (7.5A)


I chose #10 D-Op +B since it's under 10A.


The options I have found for the white wire include:


#16 ILM (15A)

#26 IG1 (15A)

#31 ACC (7.5A)

#33 Unit IG2 (7.5A)


Again, I chose #33 Unit IG2 since it's under 10A.


Finally, we have the orange wire, which is the one I think that I don't have right.


The only option I found suggested anywhere for the orange wire in the LGT fuse panel is #31 ACC (7.5A).


I used a Volt gauge to test the setup. When I turn the key over, I seem to have the correct power and operation. I have the sweep in the exact right timing with the dashboard sweep. I can use all of the programming functions on the gauge using the touchpad attachment.


The only thing I don't seem to have working correctly is the nighttime color switch when I turn on the headlights. This means the orange wire is not hooked up correctly. The orange wire should be hot only when the lights are on. When I flip the lights on, I get no change in behavior.


Can I actually get a fuse in the fuse panel that is hot only when the lights are on? #16 ILM sounds rather promising, but it's a 15A fuse and I don't want to start randomly plugging things in. Can anyone suggest a fuse to use in the LGT fuse panel? If I absolutely have to, can I use some wire coming out of the steering column? There must be something over on the left that will make this work correctly. Ideas?




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Look for a radio fuse and see if it is hot all the time hot not. I would start with that one. If not look for the fuse for the fog lights or gauge cluster lights. I am running out of ideas. I keep my lights on all the time so that would not be something that i would be using.
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Note, I do have day time running lights disabled, not that I think that should matter in this calculation. There is definitely a fuse in there labeled Fog or some such similar. That was going to be my next guess. I'm just not sure if that's only on with the lights or only on with the fogs. Which would not be the end of the world, since I run with my fogs on any time the lights are on, but still that seems like a hack and not a correct solution (if that is indeed the way it works). :)


I do feel like gauge cluster lights is maybe the right one since it changes intensity when I turn on the headlights at the stalk, but maybe that's not a matter of on or off at the fuse, but rather just the intensity of the draw (always hot when key is on?).


Guess I'll need to start trying things out. Or better yet ... maybe I should pull out my electrical tester thingy and give that a whirl. Guess I need to figure out how it works some time.

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Yes you will need a test light to figure out the correct circuit to be on. For the orange wire "tail lamps" in the fuse box is always a good one as you want to try to stay off the radio or dash lights as they are dimmable which means if lights are turned down too low it does not have the 12v needed to trigger the gauge to change colors. Check out the top right video here to show you how to use a test light and check the fuse box. http://prosportgauges.com/premium_series_peak_warning_gauges.aspx
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Alright. Power Probe III to the rescue. I found a winner. It is a 15A fuse, so I hope I don't blow out the fuse taps somehow, but I've got some behavior. So everything still hooked up as above, except now I have the orange wire running off a tap that is plugged into ...


#14 Tail Clearance 15A (I guess there's the tails you mentioned, but what the clearance refers to I have no idea). But this fuse is negative when just the key is on and positive when the lights are on at the stalk.


One further question though. When I turn on the lights at the stalk, the gauge appears to dim rather than change color. I can put it in amber, white, or blue with the same behavior. It just dims to a dimmer version of the same color when I turn on the lights. My understanding was that these would go from white to amber when headlights are engaged. Did I misunderstand or confuse the gauge series and their functions (premium vs. halo) or is there some setting I can use to set that behavior? This is not a dealbreaker for my happiness, just different from what I expected.

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I hope you installed your fuse taps oriented in the right direction. One side of the leg/spade is "hot" while the other side isn't. Your two fuses on the fuse tap should operate independently of one another. If one fuse burns out, it shouldn't affect the other. If you have it installed backwards, I believe it won't work this way.


As far as amperage goes, you should be just fine but strictly speaking, you should've tapped into a fuse that was rated to something higher than what the fuse on your tap is rated. This ensures that the hot line actually running to your fuse box can handle that current.


If you're tapping into the 7.5A line and your tap's fuse for your gauge is 10A, on the off chance that your gauge actually pulls 10A, there's no guarantee that the wiring you tapped into (the 7.5A hot connection) can actually handle it.


This is really academic though since 1) your gauge shouldn't ever draw 10A and 2) I have a feeling that the wiring to the various fuses in the box is actually the same gauge so it should handle it just fine. It's the other wiring in your car AFTER it passes through the fuse that might not be rated that high.


Also, you're supposed to keep the amperage of the original fuse that you plugged into. If you tap into a 7.5A line, you're supposed to keep the 7.5A line for the fuse that powers what it used to power, and 10A (or whatever you choose) for the gauge. If yuo're tapping into a 15A line, then it should remain a 15A fuse (reuse the fuse) and 10A (or whatever you choose.) The reason the package tells you not to exceed 10A is because the little wire that is attached to the fuse that goes to your gauge is thin. However, I've checked before and based on the gauge, the wire usually can handle more than 10A.

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A bunch of really useful info that I know nothing about


Thanks iNVAR! I'll have to take a bunch of this stuff into account when I do the final wiring harness. This was just a test to make sure I could get it to work, but when I hook everything up, I would like to have it done right.


Pardon my newbiness, how do I know which direction to orient the taps?


Ah ha! So I'm actually better off in the 15s than the 7.5s. Good to know. That actually makes perfect sense now that you lay it out for me. Lemme go move things around in the test harness and see if they still work.


Did reuse existing fuses for all tapped fuses. Used all 10s in the new slots for the gauges.

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With your gauge disconnected, if you have a multimeter, you can easily test it by checking the voltage. Plug in your fuse tap and have all the fuses in. For the line that runs to your gauge, test the voltage by touching the + lead to the wire, and the - to a grounding source. It should read 12V, give or take. Yank out the fuse responsible for the gauge and your wire should go dead. Test the electronics (roll up your windows or whatever the car fuse is responsible for.) They should still work. Plug that fuse back in, and then yank out the other fuse that's responsible for the other stuff. You should still be getting 12V at the wire for the gauge even though the other fuse is out. Check your electronics (roll windows up, etc.) and it should not be working since you yanked that fuse.


Or if you don't have a multimeter, just see if the gauge goes on and then off when you're yanking the fuses. Multimeter is safer though.

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I've seen that pic. Something somewhere along the way convinced me that it wasn't quite right. But clearly I've made a few assumptions that were backwards. Honestly, I've seen enough conflicting info to have confused me, but I think I've got the full understanding now to do this all correctly. Thanks all. Will report back with final results and possibly more questions. :)
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