Stop Lamp Relay/CHMSL 2016 Silverado

[Dfox]

I'm having issue with my 2016 Silverado CHMSL and after looking at the wiring diagram I think my issue is the stop lamp relay being faulty. The wiring diagram says the stop lamp relay is in the underhood fuse block, but I can't find that in the fuse block or fuse diagram. Where is the stop lamp relay?

[JimCost2014]

2 hours ago, Dfox said:

I'm having issue with my 2016 Silverado CHMSL and after looking at the wiring diagram I think my issue is the stop lamp relay being faulty. The wiring diagram says the stop lamp relay is in the underhood fuse block, but I can't find that in the fuse block or fuse diagram. Where is the stop lamp relay?

Welcome to the site.

 

Fuse #38 in the under hood fuse box is the one for the 3rd brake light, not sure which relay controls it.

[Dfox]

8 hours ago, JimCost2014 said:

Welcome to the site.

 

Fuse #38 in the under hood fuse box is the one for the 3rd brake light, not sure which relay controls it.

Me neither, I took out every relay i could see in the underhood fuse box and my issue was the same and none of them are the stop lamp relay.

 

Even with every relay out (all I could figure, at least), you could here clicks like a relay was operating when I pressed and released the brake pedal.

[newdude]

11 hours ago, Dfox said:

I'm having issue with my 2016 Silverado CHMSL and after looking at the wiring diagram I think my issue is the stop lamp relay being faulty. The wiring diagram says the stop lamp relay is in the underhood fuse block, but I can't find that in the fuse block or fuse diagram. Where is the stop lamp relay?

 

 

 

The relay is in the fuse box.  Literally.  Its an integral/printed circuit relay that is internal to the fuse box.

 

To replace it?  You must replace the fuse box.  

 

Also, a list below of the other relays that are PCB relays:

 

Note: Relays listed below are non-serviceable Printed Circuit Board (PCB) relays and are internal to the block.
—	—	KR3 Horn Relay	—	F48UA
—	—	KR11 Windshield Washer Pump Relay	—	F54UA
—	—	KR12B Windshield Wiper Relay	—	KR12C Windshield Wiper Speed Control Relay
—	—	KR12C Windshield Wiper Speed Control Relay	—	M75 Windshield Wiper Motor
—	—	KR46 Front Fog Lamp Relay	—	F49UA (T3U)
—	—	KR48 Headlamp High Beam Relay	—	F58UA
—	—	KR59 Stop Lamp Relay	—	F38UA
—	—	KR61 Trailer Backup Lamp Relay	—	F16UA, F33UA
—	—	KR63L Trailer Stop/Turn Signal Lamp Relay-Left	—	F14UA
—	—	KR63R Trailer Stop/Turn Signal Lamp Relay-Right	—	F17UA

Edited October 23, 2021 by newdude

[Dfox]

5 minutes ago, newdude said:

 

 

The relay is in the fuse box.  Literally.  Its an integral/printed circuit relay that is internal to the fuse box.

 

To replace it?  You must replace the fuse box.  

That's fantastic. So instead of a $6 relay, a $150 fuse box. I was thinking it might be something like this (as I still could hear a relay clicking when all relays were out) but really don't know much about fuse box internals.

 

Thank you.

[JimCost2014]

14 hours ago, Dfox said:

That's fantastic. So instead of a $6 relay, a $150 fuse box. I was thinking it might be something like this (as I still could hear a relay clicking when all relays were out) but really don't know much about fuse box internals.

 

Thank you.

Yea, unfortunately had the same thing happened to me in my 2008. 

 

3RD brake light stopped working, replaced fuse, nothing, replaced brake light unit itself, nothing, trip tp dealer and $500.00 later it worked like new. Was not sure if they had changed the design (fuse box) or not in the K2's.

Edited October 24, 2021 by JimCost2014

[014LTZ]

Did replacing the $150 fuse box under the hood fix this issue? My third brake light isn’t working and I’ve tracked it down to the fuse box and no power to the fuse #38. Still he at the clicking but all the research I’ve done says it’s the relay that I can’t find there unless it’s built into the fuse box.