A friend has a van, the fuel gauge does not work, his mechanic says it is the ecm. Apparently the mechanic was able to move the needle on the gauge with his scan tool, and was able to see a signal from the sending unit.

Is this possible for me to check with vcm scanner?

I also have another ecm with matching hardware and os (from a 4.3l 1500) I can swap in, but before I spend the credits I would like to know it will work.

Should the fuel gauge work if I just plug in the other ecm?

numbers for both ecm's:

serv. # 12602801

hdw. # 12589161

os # 12597120