Is halls effect working properly ?

I have dual GRT Hxs and an EIS. Just finishing the wiring and the amp indicator is not working on the EIS or EFIS properly (showing -3 no matter what load is on). I have chatted with GRT and have all of the setup correct (decimal, interger, etc). The halls effect (green donut) has the alternator hooked up on the rt side and the battery (relay) on the left side. The wire is running through the donut with the arrow pointing to the left (ie the battery as per the diagram for flow).

They say I need to put a new one in (they will cover). Problem is that it is buried in the front baggage bottom area and will be a real pain to get to and replace (because I have a lot up stuff in there).

I assume it should vary the amp reading with different things on and off because it is reading the "system" electron flow? There is no flow from the alt (hence the neg reading). Does that make sense? I just would hate to work on it for five hours and find out the "new" one is showing the same. It is getting the 4.8 volts required.

Does anybody have any experience with this and might be able to give some input? I would think it does need to be replaced because I would think it should show a variation in amperage with just the battery on and various things being turned on and off. It's the same as if the alt fails. Or, does the alt need to be producing power through that wire for it to show, and it doesn't work accurately once it fails? I'm obviously not an electrical expert because I'm asking a probably obvious question like this. Thanks. Dave

I believe the only time you will see a reading is when the alternator is putting current out to the battery. it will indicate how many amps the alternator is suppling to the system. Current has to flow thru the donut to get a reading. This will only happen when the alternator is prducing power.