Ignition hot relay connection

[Grgg1978]

Hey guys I've actually been searching the information for this question and can't seem to find an answer yet.

I am working on putting an auxiliary fuse box in the engine compartment and I am trying to figure out where I can connect a relay to activate theonly when the car is on or accessories are turned on. Where is a good wire to tap into to activate the relay.

Thank you ahead of time.

 

[octanejunkie]

You seem to be asking two separate questions, or I don't understand what you are trying to accomplish, so here's a question back to you: do you want your entire AUX fuse box powered only when the car is running, or ignition on?

If the answer to that is yes, then you would have to size that relay according to the max amperage of all the fuses combined in that AUX fusebox, and I would still want to fuse it.

IMO, it would be cleaner and easier to bus feed a series of fuses and relays from ignition-on power with a master fuse on the AUX fuse box. This way you can isolate wiring problems or short circuits after the AUX fuse box, rather than blow fuses every time you turn the key on in the event of a problem.

 

[Grgg1978]

I want the fuse box to be active only when the ignition is on kinda like the radio. I just need to know where I can attach pin 86 on a 4 pin relay to give power to the power to the fuses.

 

[TheDurk]

I want the fuse box to be active only when the ignition is on kinda like the radio. I just need to know where I can attach pin 86 on a 4 pin relay to give power to the power to the fuses.

It's not that easy in the engine bay. All those engine room fuses are powered full time. The best point I can think of is at the Power Outlet Relay which is in the engine room fuse box. Pin 1, the gray wire, comes off the ignition switch, so that the relay is energized only when the key is on.

 

[octanejunkie]

Assuming you are using a 200 Amp split charge type relay, you can tap into any 12V positive ignition-on circuit, but there aren't many in the engine bay.

Check the 7.5A fuse connections in the fusebox with your multimeter and see this thread http://www.toyota-4runner.org/5th-gen-t4rs/216027-switched-12v-under-hood.html

 

[theesotericone]

Assuming you are using a 200 Amp split charge type relay, you can tap into any 12V positive ignition-on circuit, but there aren't many in the engine bay.

Check the 7.5A fuse connections in the fusebox with your multimeter and see this thread http://www.toyota-4runner.org/5th-gen-t4rs/216027-switched-12v-under-hood.html

That. You just need a 16 gauge wire and an add a fuse. The wife has my rig right now but when she gets back I can check which one I tapped.

 

[TheDurk]

Assuming you are using a 200 Amp split charge type relay, you can tap into any 12V positive ignition-on circuit, but there aren't many in the engine bay.

Check the 7.5A fuse connections in the fusebox with your multimeter and see this thread http://www.toyota-4runner.org/5th-gen-t4rs/216027-switched-12v-under-hood.html

You did see where that thread is from the 5th gen forum and the mentioned fuses do not exist in our trucks? I based my statement on the correct EWD and I stand by it for a 1999 or 2000 rig. Any suggestions, it would be nice if people GAVE THE YEAR!!!!!

There are plenty of ignition switched fuses in the inside box but none in the engine bay, as far as I can see. You know the EFI fuse is full-time, because if you cut that circuit you reset the ECU mapping. We don't have a EFI #2.

 

[theesotericone]

You did see where that thread is from the 5th gen forum and the mentioned fuses do not exist in our trucks? I based my statement on the correct EWD and I stand by it for a 1999 or 2000 rig. Any suggestions, it would be nice if people GAVE THE YEAR!!!!!

LOL. There are a few switched fuses in our drivers panel fuse boxes though. Just add a circuit there and run it through the firewall. That's how I did it as well as a few other guys here. My aftermarket accessories are only hot when the key is on. If your adding accessories you'll need to go through the firewall anyway to get power from your carling swithces. If my wife ever gets back with the rig I'll grab a photo of what I tapped.

I'm sure your right about using the engine fuse block but for me it was easier to just use the interior box.

 

[TheDurk]

LOL. There are a few switched fuses in our drivers panel fuse boxes though. Just add a circuit there and run it through the firewall. That's how I did it as well as a few other guys here. My aftermarket accessories are only hot when the key is on. If your adding accessories you'll need to go through the firewall anyway to get power from your carling swithces. If my wife ever gets back with the rig I'll grab a photo of what I tapped.

I'm sure your right about using the engine fuse block but for me it was easier to just use the interior box.

Correct. But he didn't want to do that, and your post sounded like you had tapped an engine bay box fuse and that don't work. The thread you cited was from a 5th gen where they did tap an engine bay fuse--that we don't have, so I thought the whole thing was easily misunderstood. I agree it is probably easier to go through the firewall rather than opening up the engine bay box and tapping a relay from inside, but it is an option. Tapping a fuse in there is not.

 

[octanejunkie]

I originally started typing he should just do what he didn't want to do, tap into the switched radio fuse/circuit as it's easy to get to and easy to hide, but the question was specifically about IN the engine bay.
[MENTION=10169]TheDurk[/MENTION] is correct, I did FAIL to notice and/or cite the generation of the link I posted, nor did I attempt to qualify what vehicle the OP was working on, therefore it's a gross fail on me.

 

[Grgg1978]

Ok. So I can basically tap into the cigarette lighter wire for the relay because it's only on when the vehicle is on.