New battery and new alternator-DEAD

[GTS61]

I installed a new battery and new alternator. It’s a 305 V6. Started it up and watched the volt gauge go from 12 to 0. Any idea’s why this would happen? Thanks

[AZKen]

Assuming you installed/wired it all up correctly, we will then have to assume a bad part or a bad battery. Does not matter if things are "new" or what the dash gauge says for now.

First thing to do is get a multimeter set on DC volts. Touch on battery posts while motor not running to see if it reads around 12.6V. Then at high'ish idle, see if it reads 14V +. Be SURE to touch the battery posts, NOT the cable clamps. Report findings.

If you don't get these voltages, clean all cable ends and battery posts (neg and pos) and cable ground locations with a good wire wheel or brush. Check all alternator connections. BE SURE there is no paint, corrosion or plating preventing the new alternator case or brackets from being grounded. Then repeat tests.

[GTS61]

Thanks Ken I found the problem. I did check the battery after charging. And with my multi meter it was reading 12.3. But the numbers touching case of alternator was the same and the truck was running. The last thing I did was take off the pos. cable off of solenoid to clean it and found a bad fitting. Runs like a kitten now!