Looking for TRUE IGNITION SOURCE in 2009 Sierra Denali 6.2L

[_Nomad_]

Ok guys, title says it all. I need to find a true IGNITION power source. Not accessory power or constant power but I need power to the circuit ONLY when the engine is running and at no other time, regardless of what position the key is in. Only when the engine is running. That rules out RAP too.

 

I have scoured the search function here and only find accessory power locations and a really nice write-up on RAP. Unfortunately that doesn't help me.

 

Anyone know where to find a true ignition source under the hood in a 6.2 litter 2009 Sierra Denali?

 

Thanks in advance for any help you guys can give.

 

Oh, and for your help, I give you this...

 

[_Nomad_]

I guess I should also add that I have tested about every circuit in the underhood panel with a DMM and did not find one.

 

I could have overlooked one though.

[gmtech4]

alldata.com,

 

$27/yr

 

thats what ya need ,not us here

[scooby5121]

What do you want to operate , just wondering.

scooby

[Wires]

You should be able to find it under the dash, driver side.

 

I do not believe there is just a spare spot, you'd need to tap into something.

 

I'm wondering what scooby5121 is wondering. The cig lighter works good, but I think that still has power in accessory mode.

[_Nomad_]

alldata.com,

 

$27/yr

 

thats what ya need ,not us here

 

 

So you're saying that no one on this GM-Truck forum knows where ignition source power is on a GM truck?

 

Thanks for the suggestion, but I have faith in the forum members. For example, I could tell what circuit, plug, wire or orifice to tap on most any year Corvette. I just figured there would be some serious enthusiasts about GM trucks here. I'm sure there are.

 

What do you want to operate , just wondering.

scooby

 

 

I'm wiring in a dual battery setup. The ignition source is so the isolator relay can sense 12 volts to activate it, but only when the engine is running, or it kind of defeats the purpose of a battery "isolator". I am familiar with the VSR (voltage sensitive relays) that don't require tapping an ignition source, but they don't have high enough amperage ratings for my needs.

[_Nomad_]

The cig lighter works good, but I think that still has power in accessory mode.

 

 

It does.

[_Nomad_]

Lemme guess, everyone is just staring at the GIF I posted...right?

[scooby5121]

Tap into the throttle positioning sensor

[nht mike]

Look on your alternator for a S terminal. That's what we would use for a starter blocking relay so the starter won't engage while the engine is running. If you don't see it check with an alternator shop. The fuel pump relay or the oil pressure switch that controls the fuel pump relay maybe another choice.

 

Mike

[_Nomad_]

Tap into the throttle positioning sensor

 

Look on your alternator for a S terminal. That's what we would use for a starter blocking relay so the starter won't engage while the engine is running. If you don't see it check with an alternator shop. The fuel pump relay or the oil pressure switch that controls the fuel pump relay maybe another choice.

 

Mike

 

 

 

Thanks guys, I'll check them out.

[ujtruck]

under hood fuse box - RUN Relay fuse

[_Nomad_]

Thanks for all of the reply’s guys, I really appreciate the help!

 

I found the 12v ignition source!

 

It is located in the Mid-Bussed Electrical Connector in the driver side floorboard, behind the parking brake. It’s at port X-14 pin # 7.

 

Here’s a picture of the MBEC:

 

 

Here is a close up of the empty connection bay. Pin # 7 is a true 12v ignition source.

 

 

Thanks again for the reply's guys and I hope this helps someone else.

[Wires]

Thanks for posting back about that. Definately handy knowledge.