Part Number for inadvertent power relay
#1
03-15-2019, 07:27 PM
Part Number for inadvertent power relay
I'm chasing some intermittent electrical issues. Hitting bumps and pot holes causes my interior lights to flicker
and I can hear a relay clicking behind the instrument panel as it happens. The interior lights shouldn't be on anyway.
I have factory service manuals and can follow schematics; done plenty of research. First thing I want to investigate
is the inadvertent power relay & courtesy lamp relay. They are located on a relay block buried up under the dash
behind the instrument panel. For peace of mind, I would prefer to have new relays in hand as I look at this block.
I went to the local dealership and the parts guy couldn't find a inadvertent power relay in the system. He's been working
there for decades and I trust him. I googled the heck out of it and drew a blank.
???????
and I can hear a relay clicking behind the instrument panel as it happens. The interior lights shouldn't be on anyway.
I have factory service manuals and can follow schematics; done plenty of research. First thing I want to investigate
is the inadvertent power relay & courtesy lamp relay. They are located on a relay block buried up under the dash
behind the instrument panel. For peace of mind, I would prefer to have new relays in hand as I look at this block.
I went to the local dealership and the parts guy couldn't find a inadvertent power relay in the system. He's been working
there for decades and I trust him. I googled the heck out of it and drew a blank.
???????
#2
03-15-2019, 08:27 PM
Check ALL your door hinge pins/bushings as well as the latches for wear. If worn the door can jiggle just enough to make the switch arc and lightly flicker the lights
Last edited by odat; 03-15-2019 at 08:31 PM.
#3
03-16-2019, 12:08 AM
Word confusion. "Inadvertent" means accidental, so if you're searching for inadvertent of course you're not going to find anything. 
The part for the "intermittent" blinker relay is ACDelco 11516051, actually called the Hazard Warning and Turn Signal Flasher. The courtesy light relay is ACDelco D1786C (#19116057) but it's used for several things like the horn so you probably already have one on hand to swap for troubleshooting.
I'd agree with odat though that while it could be the relay, that would usually mean non-functioning lights. I'd want to look for wear/play in the door switches before throwing parts at it, and don't forget about the tailgate.
The part for the "intermittent" blinker relay is ACDelco 11516051, actually called the Hazard Warning and Turn Signal Flasher. The courtesy light relay is ACDelco D1786C (#19116057) but it's used for several things like the horn so you probably already have one on hand to swap for troubleshooting.
I'd agree with odat though that while it could be the relay, that would usually mean non-functioning lights. I'd want to look for wear/play in the door switches before throwing parts at it, and don't forget about the tailgate.
#4
03-16-2019, 07:17 AM
A faulty relay to cause that very unlikely, at most would be opposite where lights would not stay on when supposed too. A short that triggers the relay has a much bigger chance of occurring but still not something that is common. I’m with the majority, door switch or poor connection from the door switch detection line input to the BCM. On my 98 the switches have plug connector on inside of the car side of those buttons that contact door jam. You should be able to test each side door by unplugging them one at a time.
The tailgate depends on which gate you have, the 2 piece like mine (98) the button is right there where the release handle is. I note tho, if this was the fault the rear wiper should not work when those interior lights are on. That switch not only kicks on the interior lights but also lets the BCM know gate glass open and rear wiper can not run.
The tailgate depends on which gate you have, the 2 piece like mine (98) the button is right there where the release handle is. I note tho, if this was the fault the rear wiper should not work when those interior lights are on. That switch not only kicks on the interior lights but also lets the BCM know gate glass open and rear wiper can not run.
#5
03-16-2019, 09:04 AM
No word confusion, the factory manual calls it a inadvertent power relay.
It's a protection circuit so you don't run down the battery by accidentally
leaving the interior lights on when you park the truck. The inadvertent
power relay triggers the courtesy relay.
I'll take a look at the hinges and door switches next.
Funny thing about the tail gate (2 piece) randomly I find the gate glass
unlatched as if someone hit the button on the dash.
It's a protection circuit so you don't run down the battery by accidentally
leaving the interior lights on when you park the truck. The inadvertent
power relay triggers the courtesy relay.
I'll take a look at the hinges and door switches next.
Funny thing about the tail gate (2 piece) randomly I find the gate glass
unlatched as if someone hit the button on the dash.
#6
03-16-2019, 09:29 AM
I agree, unplug/ short switches until the problem goes away. Given the “inadvertent” ;-) hatch glass trigger and improper interior light function together, look for what’s common besides the BCM - wiring harness shorts/corrosion, etc. you sound like you know how to look at a schematic but if you need help with a diagnostic sequence to figure it out let me know and I’ll trace through your schematic and help you with that. We all have different skills on this forum but I live to solve impossible electrical problems.
George
George
#7
03-16-2019, 08:50 PM
No word confusion, the factory manual calls it a inadvertent power relay.
It's a protection circuit so you don't run down the battery by accidentally
leaving the interior lights on when you park the truck. The inadvertent
power relay triggers the courtesy relay.
I'll take a look at the hinges and door switches next.
Funny thing about the tail gate (2 piece) randomly I find the gate glass
unlatched as if someone hit the button on the dash.
It's a protection circuit so you don't run down the battery by accidentally
leaving the interior lights on when you park the truck. The inadvertent
power relay triggers the courtesy relay.
I'll take a look at the hinges and door switches next.
Funny thing about the tail gate (2 piece) randomly I find the gate glass
unlatched as if someone hit the button on the dash.
If it's not explicitly listed it's probably just named "relay" (kind of like the fuses aren't all explicitly named either) which should be the 19116057, but that's just a guess.
I'd still be suspicious that the problem is elsewhere though, especially with that lift glass issue. If the "gate open" light comes on when the lights flicker too I'd bet that's the problem. Maybe hit the latch with some WD-40 or such and see if it's sticking? And if nothing else the tailgate is a lot easier to get into and investigate than the dash. It's probably not the switch since you would hear it and it should only fire when it's in park.
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