Need 12V hot ONLY when key is on:

[vandelay industries]

On the fuse panel, is an "Accessory" slot, the same as an "Ignition" slot?

That is, are the "Accessory" slots only providing power when the key is in the "on" position ONLY----like an "Ignition" slot?

i'm running out of slots which is why i'm asking.

 

[diesel4me]

Only way to be sure is to use a test light to ensure your only getting power in the "on" position...
In my experience some fuse boxes in GM trucks have extra "ACC" spots in the fuse box,but some have power in both the accessory position and "on",and another may only have power in the key "on" position only..

 

[obijuank5]

Look up the factory service manual for the year fuse block you're working with. It will identify all the oem hot locations on the fuse block.

 

[vandelay industries]

Only way to be sure is to use a test light to ensure your only getting power in the "on" position...
In my experience some fuse boxes in GM trucks have extra "ACC" spots in the fuse box,but some have power in both the accessory position and "on",and another may only have power in the key "on" position only..

So, the clip gets clipped to a ground source and you just stick the other end into a slot and if it stays off when the key is off and then turns on when the key is on, then i'm good?

You'll have to forgive me as i have not done that much electrical work, but i'm open minded to it.

 

[rampage]

Yes.
Or you could use a 12V bulb to do the same thing - one clip to outer casing on bulb other wire to bottom of bulb, doesn’t matter on polarity.
Or you could use the correct tool for the job - a multimeter. I suggest getting one and take 5 mins to learn how to use it. Do you change your wheel bearing without using a hub socket and hobble something together?

 

[diesel4me]

A test light is all you need,I find one easier to use than a multi-meter for just seeing if a circuit is live,with my crappy up close eyesight..

I've also used one of those annoying buzzers that plug in the fuse box that remind you a door is ajar,or the keys were left in the ignition..

Just hook two wires to it with alligator clips on the other end,ground one of them and probe the 12V tap you want to check with the other wire..this lets you hear instead of just see if it has power,and that is a plus when your crawling under the dash and cant look at the light or a meter easily..

If your only needing power when the key is "on" but not in any other position,be sure to check and see if its getting power in the "ACC" position on the ignition,you do not want something like an ignition coil getting power in the "ACC" position,it'll stay on and possibly fry..

Also the power will be temporarily interrupted when you turn the key to the "start" position,some things like a stereo memory or a GPS may lose their memory when the power is interrupted during cranking..

 

[vandelay industries]

Thanks. i think we can close the thread now unless someone has anything else to add or i re-open it up later if needed.

 

[dyeager535]

Ignition would be any position with key turned "forward". Accessory is all of those positions plus key turned backwards, like the radio.

Assuming this is a blade fuse block, GM used "piggyback" connectors on the fuse panels in some applications, so you could run multiple wires off the same terminal on the fuse block.

However, realize those accessory terminals arent fused separately...most or all of those terminals are powered off the small relays on the fuse panel (and ganged, usually 3+ terminals to one relay), 30A IIRC, so you run the risk of overloading the relay, or not fusing the accessory properly (say your accessory is supposed to be 5A fused) If you need to fuse something, better off adding an auxiliary fuse panel to fuse each circuit individually.