Low voltage on activating wire

[andrewsailor]

New poster here - I have a 2007 3.0 L on which I replaced the alternator a couple years back. Last couple drives the battery light has been coming on and off, I'll lift the hood and wiggle the activating wire and hear the engine revs change as the light goes off. Long story short I've verified that the connection is good at the alternator, and it is now charging at 14 volts, however, the activating wire has only 7 volts on it. I've got a long trip coming up soon, and I don't really feel keen on breaking down. There should be 12 volts on this wire, correct? What should I check?
Thanks!

 

[andrewsailor]

Although... I did assume this was the activating wire, but I just read somewhere that the purple wire coming off the three wire plug and connecting to its own spot on the alternator is actually the stator circuit. In which case, I would still assume that 7 volts is not normal?

 

[Curious Hound]

I don’t have a diagram handy for your truck. However, the voltage regulator is going to vary the voltage going to the stator in order to control the output voltage from the alternator. This will change depending on electrical load on the system
And engine rpm.