Battery draining

[dave's70]

My battery keeps dying out on me if I don't start my truck for a couple of days. I have replaced the battery, altenator, and the starter. My motor is a 350 out of a 77 truck. I can't find any bad wires that could be the problem. Any advise would be greatly appreciated.
Thank Dave

[Longhorn Man]

With everything turned off, disconnect either batery terminal. (neg is safer though)
Connect a test light to the post, and then to the cable. If the light lights up, you have a problem, something is putting a load on your system.
First thing, unplug the plug on top of the alt. if it goes out, that is your problem. If it stays on, time to do the Under Dash Boogie and start pullin fuses untill the light goes out. Once it goes out, you need to look into the circuit that you just pulled the fuse out of.
did you install an amp or stereo right about the time this all started? How about a voltage regulater? Any electricla work you may have done right before the problem started would be the first thing I would look at.

[Hooter]

it is typically a short or sometimes u just get a bunch of crappy batteries. try a different brand of battery next time you replace it

[Southpa]

Measure the voltage across the battery, if its not around 13 v. + then you aren't getting the juice you need from the alternator. If you are sure that all the components , ie. batt., alt, voltage regulator etc. are good then you likely have a ground problem. I've been told that horn relays in these trucks can be notorious for grounding problems.

I ended up just by-passing all the circuitry and ran a heavy wire directly from the back of the alt to the pos. battery post. that was about 6 years ago and I haven't looked back since. I know its a bit of a cheat, but it works fine, got 13.8 volts across the battery when it used to be 11v.