So, my vehicle is a '99 Blazer LT. Last summer the interior lights went flaky and the cause has baffled me ever since. Using a schematic I had, it seemed to me the symptoms I was getting pointed to a stuck relay. The Shop Manual for the '99 indeed shows that there's a Body Relay Block containing a relay for the courtesy lamps PLUS nine more. It says this relay block is located "left side of dash, right of I/P Fuse Block".

I've had the whole dash apart on the left side and dismounted the fuse block. I've stuck a light, and my hand up in there all over the place, but there's simply no relay block up in there that I can see, feel, or find. Anyone who knows where that fuse block is, please chime in and enlighten me, please.

Picture taken from '99 S/T Truck Service Manual, Book #3.

 

It’s under dash on drivers left side of foot well . It’s mounted upside down with two clips . It’s not easy but can get to it and get it down without removing dash . It contains relays for locks, lights , windows
Search “ body relay block location “ or “door lock relay location “ and there should be an older thread with good photos
Or if you scroll down in this thread you should see a “related thread “ that also has pictures and info

https://blazerforum.com/forum/lighting-electrical-52/body-relay-block-location-removal-schematic-81664/

 

Thanks a heap

I seem to remember seeing the lower part of that thing but I didn't recognize it as a relay box. I thought it was a junction connecting the body harness to the engine compartment. Hard to believe they made it so inaccessible. Makes me think I should replace them all once I get access. I don't want to do this job again.

 

Try this link:

https://blazerforum.com/forum/lighti...hematic-81664/

 

Thanks Christine. I did see that, and also yours. You seemed to think it was unnecessary to disconnect the harness, and that it could be disengaged from the support by pushing up on it to clear the upper hooks, then just sliding it down. I tend to agree because that's a common method of attaching plastic things like that. And designers don't tend to make it overly complicated to access common service parts like bulbs, fuses, and relays. I'll find out soon enough, but I don't relish the thought of working under the dash in the cold, so I'm gonna hold off until conditions get a little more comfortable.

Once again, this forum proves its worth. I would NEVER have recognized (what little I could see of) that box as a relay panel, and didn't when I was fishing around up in there. Until I learned there were 10 relays total (instead of 2), I thought I was looking for exposed relays on a small flat panel located right behind the fuses.

 

I couldn't get it disengaged by pushing up on it. The lower hooks aren't flexible enough. I used a wire hook, and alot of effort, to pull down on each one individually to just barely clear. It wasn't easy, but I finally got the box free of the mount. Waiting on delivery of new Omron 12088567 relays. The box uses three of them. Dreading the effort to get box re-mounted.