91C1500sleeper

So after 3 years of the turbo 400 behind the sbc I finally had enough. I got a free NV3500 and all the parts needed to do the swap. It was pretty straight forward. Just a few things to tend to and all will be good. I did alot of searching and research before I tackled the swap. The motor is mildly built with a nice cam and vortec heads and the FiTech efi. The exhaust drone that I had with the turbo 400 is gone now. It is peppier in 2nd-4th gear. The truck has sat for the last 7 months so I need to clean the fuel system and tidy up under the hood. If your on the fence about the manual to auto swap I highly recommend it.

91C1500sleeper

So I ditched the fitech for a carb. Truck runs ALOT better and more responsive. I did buy an AEM AFR gauge to help dial in the carb. According to the instructions I just needed to hook the red wire to a 12V key'd wire and the black to a ground. The gauge does not work. Am I missing something here?