What is causing a power drain on battery i have a new battery and a new alternator installed a week ago and when put on a load tester everything shows good, when car is not running load tester shows a power drain, also a loud clicking noise comming from the fuse panel.

Modern cars have parasitic drain from all the computerized control. It requires systematic approach to identify the myriad of potential causes. Eliminate any aftermarket devices which includes any plug in power supplies. After market radios, security, and remote starters are notorious parasitic drains.

How fast does the battery drain to a level that it no longer cranks? You need to verify it's recharging properly. Most auto parts stores do this diagnostic no fee.

If overnight then it's a gross drain. Over a couple days then it's a moderate load. If several weeks, it may be normal.

find a real shop to fix real hard electrical problems
seems the AZ alternator is junk, as is common there
I never buy their parts ever,DURAjunk. (go NAPA)
the PCm my be the regulator here. (dont blow up PCM?!!!!!)
do not hook up battery backwards or blow to H3LL $3000 worth of electronics!
and never replace any alternator ever with battery neg lug attached or blow things up you will, I promise
for sure the 100amp alternator fuse blows.. if lucky only it.

you have been ZONED !
ps: that dead new battery will charge up fine
\that is why new batteries are so expensive sending good batteries back under warranty.
there is no free lunch we all pay this.

had almost same proublem with my sons car ,after two alt and a battlater ,found a loose connection at starter tha was causing the proublem all is well now might want to check

If you have a drain on your battery , it would not take 18 months for the battery to go dead . What do you mean The battery gauge in the dash shows only about 1/2 power, When ? When the vehicle is running ? Not charging ! The battery gauge as you call it has nothing to do with the Battery . That's showing how much the charging system is putting .The volt's indicator is controlled by the PCM - engine computer . With the engine running should show 14.1 volts .if your only seeing 7 the charging system isn't working. The alternator is controlled by the PCM as well ! Have it check by a GM dealer .

Hi.

Make sure that you also replaced the battery. Battery elements may be shorted inside. That will result in battery draining even if the alternator is working.

If you have already replaced the battery check power across battery terminals with engine on and revving above idle.You should read voltage in a range of 13.5/14.4 volts when engine is revving at about 2K rpm.

If the voltage is still wrong after replacing alternator and battery check the voltage regulator connected to the alternator. Here the part.

If battery, alternator and power regulator are OK, test wiring to find out if there is a short to ground that is draining the battery while you drive. This fault is quite unusual with your symptoms. Check battery, alternator and voltage regulator first.

Regards.

Ginko

You need to make sure that your getting good conection to your battery. If your alternator is fine, as you stated, you might not be getting a good conection. Your alternator may be keeping your battery alive just enough when your driving. Check all connections. Hope this helps.

you should check the voltage on your batttery when the car is running. If it reads about 13.5 to 14 volts, your alternator is doing it's job. If it's less, replace the alternator. If the alternator is ok, you have a power drain somewhere, you will need a proffesional to look at it.

alternator diodes is most common cause

if the vehicle would run a substantial period of time without lights and stuff on, then i can guarantee you 100% the alternator is getting bad, may not be all the way out, but its not far from it, and if you keep driving it like that, you will be buying another battery, because i bad alternator crushes batteries, just drains the life out of em... hope this helps you.

CHECK THAT YOU HAVE AGOOD POWER FEED TO ALTERNATOR AND A VERY GOOD EARH HAD ONE A FEW MONTHS AGO IN SAME FAULT WAS APOOR EARTH TO ALTERNATOR.