I don't think you can get analog gauges to show a number as accurately as a digital gauge, which is why I said what I did.

 

I'd get an edge or gryphon and call it a day. Less work and many more features.

 

VDO & Autometer are accurate analog volt and amp meters.

VDO volt meter on my '77 R100/RS was accurate the day I got my 1st digital Fluke meter ( WMM-23 ) back in the mid 80s.
That meter just went in for service again, passing again without adjustments.

 

Does your VDO meter show you the difference between 13.9 and 14.1 volts? or how about 12.6 and 12.8?

That's the accuracy I was talking about

 

if i had the 200+ to spend i would but i dont have that cash to drop right now.

i dont care about pinpoint accuracy i just want a better general idea of the voltage instead of like 3 lines and l and h.

 

No it won't with a glance.
One would have to look at it long enough to see if the needle is above or below the 14 mark, which staring at a gauge at 55 MPH is not a smart thing to do.

What does 13.9 VDC vs 14.1 VDC vs. 14 VDC tell you about the system ? Not much, that is just information for information's sake.
~ 14 VDC indicates more than the normal band of low to high ( which is a wide margin )

Back to instrument illumination, a meter that uses a twist in incandescent bulb holder would use the instrument illumination circuit.

 

Well I guess the more pertinent question is what is the range of the stock voltmeter in the dash? Does it only show in the normal range at 14V-14.4V and anything outside of that range reads as H or L? Something you should find out before purchasing a redundant gauge that will tell you the same thing. Personally, if I'm worried about a particular number on a gauge in my truck it's oil pressure, not system voltage.

 

Not too sure what revision cluster you are asking about.

2004 -2008 the normal operation the output is 13.2 to 15.5 VDC.
This is what the PCM uses to turn off the indicator lamp on the cluster ( Generator field coil ).

The gauge on the cluster generally speaking is :
8.5-10.7 volts, Normal band start
15.8-18 volts, Norm band end

monoxide wants to install a volt meter, I would guess due to audio system installed. If you are not pushing the electrical system, a volt or amp meter would be a waste.
I don't like the look of the coin holder either, but I did not have any luck installing another DC power port ( mirror of the other side ) in that position, so it stand as a coin holder.
I am still looking for some thick black plastic that I can mount a bulkhead USB port in for charging to replace it, but it is one of those as I think to look modifications ( and I already have one next to the cigar lighter ).

 

That was my point in questioning what range the "normal" band covered on the stock gauge set. I didn't see where the OP specified any stereo system or other high-draw items. Just that he wanted an actual number for the voltage. I still think that the cigarette-lighter would be a simpler and non-permanent way to obtain this info, and can be found for $15 online everywhere including eBay. It would also give a very precise readout as opposed to an analog gauge reading somewhere between 12 and 13. It would seem pointless to me to permanently mount this type of guage unless you had a minimum of two or more amps or a ton of aux lights.

 

Now a member has to provide a reason why for a mod ?

His truck, he wants it.

Don't know why it is important that monoxide does nothing or purchases one of the cigarette lighter gauges for his truck ( which costs more than a new gauge in his case ).

It is not my thing either, that is why I still have the coin holder in there.
Then again, it is not my truck......

 

I absolutely agree that it is his truck. But if some guy came on here and said he wanted to cut a hole in the hood and make a ram-air intake out of it, you don't think it's pertinent to help them source out some better options? Hell, how many people come on here talking about how they just bought some throttle body spacer because a friend said they were the best?!! I was simply voicing an opinion that adding another gauge and the hassle of running or spicing wires to it could avoided by paying the SAME price for a simple cigarette-lighter version. He also provided info that he just lost his job and money was tight, so it makes you question why you wold bother with an extremely non-essential purchase. Not trying to ruffle any feathers, just trying to provide some different viewpoints and options which may not have been explored or considered.