strange ammeter problem need wiring

I'm installing a replacement ammeter because the cool one I have is broken. The replacement is this model: 

[url]https://cgi./1-0-Digital-ANL-Fuse-Holder-Shows-Voltage- Amperage_W0QQitemZ270171187880QQihZ017QQcategoryZ50551QQssPageNameZWDVWQQrdZ1QQcmdZViewItem[/url]

Before I went cutting and drilling, I decided to test the unit. Here's what's weird. When wired in-line between the Alternator and Battery (as shown in pic) It works fine.

[IMG]https://i27.photobucket.com/albums/c200/radioflyer1986/CIMG1376.jpg[/IMG]

However, when wired between the Battery and Sound system main power wire, the Amperage reads Zero. The voltmeter part works in both setups but either there's something strange up, or I have the the worlds most efficient sound system.

What am I doing wrong?

-------------
you can never have too much of a good thing

Probably installing it backwards. There will DEFINTELY be an "in" and an "out".

Since the voltage probably has a ground lead, and both terminals are "positive", it won't matter which way it is installed for the voltage reading to function.

The current reading will most likely be polarized. Reverse the IN/OUT leads, and let us know what happens.

-------------
It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

Reversed the current flow. It still reads zero amps when between the battery and amps, but works correctly between alternator and battery (in reverse flow)

-------------
you can never have too much of a good thing

I have a inline fuse holder like that one, except its a tsunami. When wired between your battery and amps (main power wire) turn the system up pretty high, around 3/4ths the way up on the deck and see if it reads any amps. My amp meter also reads zero wired between the battery and amps in the trunk, but when the system is turned up with the amps in the trunk pulling power, it reads up to 110 amps.

Perhaps this particular brand of Ammeter has a poor accuracy range. I'm considering a different model with a "remote" shunt. I'm told this one will work:

https://cgi./dll?ViewItem&item=190159172490

Thoughts/Suggestions?

I'm also thinking of mounting the one I have under the hood

-------------
you can never have too much of a good thing

Well, my first thought/suggestion would be to stop trying to post eBay links. They don't work, (the servers filter them out) and you should know that from reading the forum rules when you signed up. You did read the forum rules when you signed up, right?

My second though/suggestion would be that the remote shunt version would probably work better for you, they usually will, in most cases.

-------------
It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

I will try the remote shunt version.

This forum's rules differ significantly from other forums im' a member of. I must have gotten the rules mixed up. I apologize for the error.

-------------
you can never have too much of a good thing