Electrical Issues?

[Wonton93]

Good morning,
I’m having issues with my 2016 CX-5 for the past few months with potentially the electrical system.
The problem started 3 months ago after a super windy/raining weekend. I was able to open the door as usual but when I started the car, the dash lights, power windows and the trunk lock wouldn’t open. After searching around, I decided to check the battery, fuses and even the fob’s battery life. All checked out. I decided to disconnect the negative terminal for about 30 minutes and re-connected it, started the car and ok al seems to work again.
Three months later, I had my car sit around for 2 weeks without driving it due to travels and now, the problems got a lot worse.
I can’t even open the car. I had to use the key just to open. Starter button doesn’t work. Again checked the battery life (sitting around 13.2v), no problems with the fuses and all seems fine.
Did the battery disconnect, let it sit and starts like it should. But it’s been like this everyday for 4 days now. Every morning I have to go through the routine of that.

Sorry for the long post but what do you think it is?

I have LED bulbs installed all around and an aftermarket stereo. Would any of that cause a short anywhere?

 

[paris1]

How old is the battery?

 

[Wonton93]

How old is the battery?

I bought the car a year and a half ago. I haven’t touched the battery. So not sure the age of it.
Would the age matter even though it shows it’s hovering around 13.5v at all times?

 

[madar]

I'd try a new battery, not recharging the old one, a new one

 

[Wonton93]

I'd try a new battery, not recharging the old one, a new one

Yeah I’ll try that.
If the problems consists, do you think it’s the modules? The BCM?

 

[paris1]

I bought the car a year and a half ago. I haven’t touched the battery. So not sure the age of it.
Would the age matter even though it shows it’s hovering around 13.5v at all times?

If it's a Panasonic, chances are it the original. Otherwise, often times batteries have the installation date somewhere on the case.

 

[Wonton93]

If it's a Panasonic, chances are it the original. Otherwise, often times batteries have the installation date somewhere on the case.

Thanks, I’ll check it out.
Regardless the age, I should get a new battery anyway?

 

[N7turbo]

Thanks, I’ll check it out.
Regardless the age, I should get a new battery anyway?

If it's 3 or more years old, I would.