What would cause keyless entry not to work?

[Dooba]

Hmmm

Could be a possibility. But, if it got turned off somehow. It wouldn’t have a “Service Keyless system” message pop up.

I may have jumped the gun there, haha!
No harm in looking, plus I’ve checked some corvette forums that complain about the same thing in the c7. Apparently if you put it in the little cubby in the centre console it’ll kinda relearn it and fix itself?

Worst case is a trip to the dealer, you’re under warranty and they can’t blame you for it without proving that removing the third row broke it.

 

[Fless]

Have you tried re-installing the rear seat and see if it works again? It shouldn't, it should just be a red herring. A lot of people have removed the rear seat with no impact on keyless entry, including myself.

I think you will have to go through a process of elimintation to track it down.

^^^^ THIS. It's an easy way to know if the issue is caused by removing the seats, and cured by reinstalling them. Quick and easy test.

 

[wolf1340]

Problem solved. Put seat back in to see if that was the issue. While pugging it in I could hear something hitting floor. Looked under carpet and found a wire unplugged. Looks like it goes to an antenna for the keyless stuff. Looks like a little square box. Plugged it back in and all is good. Took seat back out. I must have unplugged it while pulling on the seat plug in. It’s tied in to the same harness.

 

[Sonnie kim]

Omg! I am so glad people post stuff like this online to search, i had the same problem as you, i have a 2017 gmc yukon slt and i removed the third row seats but didnt have any problems. But a few months later i had the same problem as you. And couldnt figure out what it was until i read this post! Hope it helps others who take out their third row seats. Its very easy to pull that cable out and not know it since its under the carpet and connected to the wire for the third row.
Also side note i took it to the dealer who wanted to replace the door handle and the antenna and said it would cost 1000 dollars to fix. I told them no, i would rather just use the key fob, you would think they would do a better job, this is the third time i found an answer on a forum that has saved me.

Problem solved. Put seat back in to see if that was the issue. While pugging it in I could hear something hitting floor. Looked under carpet and found a wire unplugged. Looks like it goes to an antenna for the keyless stuff. Looks like a little square box. Plugged it back in and all is good. Took seat back out. I must have unplugged it while pulling on the seat plug in. It’s tied in to the same harness.

 

[sealandsky]

Have you resolved the issue yet? Curious as to what caused it?

 

[Petruxa]

I had the same issue, here is the plug and the sensor under rear seat.

 

[sealandsky]

I was told by my local GMC dealer (so maybe incorrect) that there is a passive entry receiver near each entry point to the vehicle. At least on the front and middle seats the receiver is mounted underneath each seat. It's possible that your rear receiver is mounted under the rear seat.

 

[hnavarro1]

I had the same issue, here is the plug and the sensor under rear seat.

View attachment 245881 View attachment 245882 View attachment 245883

Hello, I had the same problem, suddenly the “Service Keyless system” appears at the dashboard, I get the code b3134-05 but I can't find the antena no 5 until I saw your photos. I access it from the 2nd row without remove the 3rd row, it's under the mat, it was bad connected, I reconnected it and now everything works fine. thanks a lot.

 

[Daddydave]

I had the exact same issue and dreaded having to take it to the dealer. I took the 3rd seat out for a road trip and half way through the handle button stopped working. Many posts are how to enable/disable passive entry. It wasn't until I found this board that I learned of the little black box under the padding. And sure enough, that was the issue!

Petruxa, a big thanks for your post and pics!

 

[Ghost10]

This might be horse shit, snake oil but when I purchased my used 18 Tahoe the dealership which btw is VERY popular, Trendy always in business and has great reviews told me every single part on the vehicle is traceable and that removing the seat could trigger a anti theft lock out or some kind of hocus pocus.