Hello new friends, was wondering if anyone might have an opinion on an issue I'm having...
The other day I went outside and found all the exterior lights on my glk350 (2014) were illuminated so I investigated but nothing appeared to be ajar or activated so after checking inside and hitting the lock button everything turned off after a few seconds. I waited about half an hour then attempted to start the car but it wouldn't turn over (there was a clicking sound like it was trying). All the normal interior and exterior lights came on along with the AC and radio, and some warning lights were activated, but nothing indicated an issue with the battery. I tried to hook it up to a 12 volt 13200mAh jump starter I have but the results were the same. I plan on getting a reader today to check the battery, which I don't think is that old (I bought the car used a year ago). Does anyone have any other advice I can try? Would the jump starter I described be strong enough to jump start the battery? Any advice would be great, thanks!

In case it helps, I'm adding a youtube link to a vid of me trying to start the car, in case theres any clues I missed. Cheers!

https://youtu.be/SUWHB3hq_Ig?si=K9uT2NXa3e9UHATE

 

How old is the battery? I would get a battery charger that does AGM batteries , a volt meter or better a cheap load tester- volt meter and fully charge the battery, that might take all day. Then test it to see if it’s any good. Or remove the battery , get it charged and tested. Many auto parts stores do this . If it’s original get a new battery . And get an AGM.. if it’s not original check to see it’s an AGM and look at terminals . Non AGM will corrode the terminals and make battery useless in a few years

 

In your video, you mention the brake is stiff. That's normal when the engine is off.

Just throwing out for comparison... for us: 2014 GLK350 Base (gas), 94k US miles in central Texas, where the summer [heat] lasts 9 months. Still have the original main battery, but we have replaced the Aux battery (trunk area) with a new one about a year ago.

I put a trickle charger on all our vehicles every couple of weeks, as a maintenance procedure. And this thread is a reminder for me, so I just now put the trickle charger on the GLK. Next, the Jeep, then the zero turn 👍

Suggestion to you - trickle charge for over 24 hrs and then load test it. Or, if the trickle charger offers a "Battery Condition" (ours does, shows good or bad), then use that info to replace if required.


EDIT: one word of caution ... if you decide to bring the battery to your local auto parts for a "quick charge and test".
That's not a proper procedure ... a "quick charge" isn't a proper method for a battery charge.