My usual guess is to check the battery just to make sure it is not the problem.
Just because it is new does not mean it is working correctly, that is why there is a Warranty.
Cold or cooler weather can stress a weak battery.
Find a AAA service center or Batteries Plus Bulbs or some other car parts store and they will check it for free.
It does not need to be below 40 deg F for them to check it.
They should use a tester that provides a printout. Look especially for "battery health". There will be a speedometer looking graphic that shows the results.
They usually check the charging system and starter. Have them check if the battery cables are secured tightly and clean.
Also note the CCAs that is measured and compare it to the installed battery CCA rating. I have noticed the CCA rating varies all over the place but should at least be higher.
If you can provide the battery manufacture, model or part number, date of manufacture, Warranty date of installation and CCA rating of the battery
to the battery tester person it will help them better estimate the condition of your battery and its life expectancy.
You will not be able to get this off of the battery because it is all wrapped up and you can't see it without removing the heat shield.
Try to find the receipt and warranty information for your current battery.
Since you have a 2015 I think you have ESS which means you should have an AGM battery.
If you have ESS you MUST have an AGM battery or the Cherokee won't work correctly
The IBS could be bad but I think only a Jeep dealer can check this.
If the battery test is good, great, look for some other problem. Test it every 3 months, eventually it WILL fail.
Is the Check Engine ON steady or flashing? Is the odometer flashing?
Apparently not or you probably would have mentioned it.
What is the part number of the relay switch? There is no such thing as a relay switch.
A relay is a relay. A switch is a switch. They do not co-mingle.