brand new battery completely flat, no lights on (1 Viewer)

[hawaiihundred]

Hi everyone!

A couple weeks ago, I bought a new battery for my hundred series, and replaced the positive terminal as it was very corroded. A few days ago, I went to the truck and found that it was completely dead. I jumped it, charged it up, and drove it for a few minutes. Three days later, completely dead again. Jump, charge, etc. Two days later, dead again.

There is also something going on with the keys. Only one of my keys will now start the car. The other key will turn the engine, but the car won't start. Sometimes, the alarm system starts honking for reasons unknown.

I live really, really far from the closest shop or mechanic. Can anyone recommend some simple tests I can do to rule out various causes? Yes, I looked carefully to make sure there were no lights on

Emily

 

[GerLC100]

Sounds like a parasitic drain to me. I'd connect a multimeter and start pulling fuses

you can find instructions easily online, here is one example:

Testing for Parasitic Draw with a Multimeter | Test Meter Pro

As long as you have a multimeter and a bit of savvy, you don’t need to be a professional to check for parasitic draw. See this basic step by step process...

testmeterpro.com

Not an expert, but I could imagine that the computer sets back some stuffs when it's dead dead. That might explain the key and alarm topic.
In other cars of friends we found a bad radio, a bad display and a bad window motor as root cause of the drain. By pulling the fuses you will know which circuit is the bad one.
Not sure if the 100 series has a TOP 5 or so in terms of drain...

 

[hawaiihundred]

Thank you so much! I'll give that a try. The electrical system is definitely getting weird, with some locks working only some of the time, etc, so I guess this isn't too surprising.