Just like the title says, I have a fully charged new battery, a brand new alternator but still have low voltage. I recently bought this rig and been putting work into it slowly by slowly because college takes up most of my time. Basically it stays at 10 the whole time. When I turn on AC and radio it will drop a lot. And when I disconnect the battery the truck shuts off. I really need help. It'd be greatly appreciated.

 

sounds like a bad wire from the alternator to the battery.... Try running a decent size wire from the alternator to the battery and see if that helps any . Make sure you disconnect the original one.

If that fixes the problem pass the wire in a neat way and enjoy the job well done. Make sure the wire is a decent size tho.

 

What kind of wire would you suggest to use? I actually tried jumper cables. One positive on the battery and one positive on the alternator. Still stays low and rig still shuts off when power from the battery was disconnected.

 

if the jumpers didnt work... then thats not the issue. Get a meter and see the voltage the alternator is giving.

 

Already been tried by him with jumper cables, but ya dont need to disconnect the other cable. I left all the original wires hooked up when I did the big 3

 

Richie did ya read my 2nd post ? =P Where have you been...

 

You think I would need a higher amp alternator? But why would the rig shut off when battery is disconnected and the alternator is brand new?

 

The alternator sounds defected.... I would check the voltage with a multi meter from the alternator with it running.

 

Lets not jump to conclusions just yet.

The alternator needs to see a reference voltage to know when to charge & when not to. If it isn't seeing battery reference, it won't charge. Reading through your other threads, I see that you have a '94 fullsize. Please put that information in EVERY thread you create asking for help so people do not have to dig for it.

Based on that, there should be another plug on the back of the alternator with a smaller brown wire that connects to the 'L' terminal in the alternator. It runs up to the gauge cluster through the 'charge' indicator & then to the 'gauges' fuse (20A). It should show 12V in RUN, bulb test, & START. If it doesn't, the alternator will not charge.

 

So what are you trying to imply? I checked all the fuses none of them are popped. Cluster works just fine all lights work and everything. I know what wire you're talking about I seen it earlier. It's dark right now so whatever suggestions you may have I'll try out tomorrow