Maybe this will help some of you. I have had this same problem with my 08 JKU for almost a year. It started with just the red security light blinking at random times. I noticed it was more frequent on hot days. Then I started to have a problem with my key fob not always locking or unlocking the doors. I tried both fobs and new batteries with no difference. The last few months I have had starting issues. Again, these where more prevalent when it was a hot day or if I went to the store and came back out. I already had a new starter and a new battery in the Jeep so I knew that wasn't the problem. Last week I literally had 2 days when I had to sit and try to start the Jeep for 15 minutes before it would crank all the way and start.
The more I thought about the times this happens it started to point me to a wiring issue. I have 142k on the Jeep and live in IL so corrosion and rust are common.
This last weekend I decided to take a day and check all the power and ground cables from the battery, fuse box and ecm/pcm. I found that the power cable from the battery to the fuse box had some corrosion at the fuse box connection so I cleaned it up really well. I also found that the ground cable from the battery to fender had some corrosion at the post on the fender so I cleaned it up. Then I proceed to check the other small ground wires from the fuse box and ecm/pcm to the fenders and found 1 a little loose and all a little corroded. I cleaned them all and replaced them.
Additionally, I was a little surprised at the lack of ground straps. I added a new ground wire from the battery to the pass side fender. I also added on from the DS fender to the alternator bracket on the engine and a third from the DS fender down to 1 of the starter mounting bolts. I used 6 gauge wire for the additional grounds.
I have gone all week now without a single problem. No red light blinking. All my key fobs work and lock/unlock with no problem. The Jeep starts right away and seems to run smoother.
All of you that are having this issue should check your wires. The nuts that tighten the small grounds to the fenders are a 10 mil wrench. The power to your fuse box is a 13 mil. My starter bolts are 18 mil. Don't forget to check both ends of the short wire that grounds the ecm/pcm to your DS fender.
Hope this helps you all. Let me know if you have any questions.
Just for kicks I also talked to the service manager at the Jeep dealer by me after I fixed everything. He said "Oh yeah, there is a service bulletin to add 5 ground wires to the Wrangler. We can do it for about 200$." I laughed and told him I already figured that out.