Switched 12V Source for New Accessory Fuse Block

[txtriathlete]

Hi, new member here with a new to me M1009. Great site with lots of useful info, I've been poking around a bit already. Did not see this specific question in the library so here goes.

Today I am converting over the stock starter solenoid using the Doghead mod. I am also planning to add a 12V SWITCHED fuse panel inside the cab to run a bunch of add-ons, including stereo, interior and exterior lights, and seat heaters (I live in South Dakota). I do not want to run that much power through the stock fuse panel. I will also be running an UNSWITCHED 12V feed for other stuff, I think I have that down - my question is about SWITCHED power only.

Question 1: Can I run a dedicated wire from the purple striped terminal (switched 12V) of the new solenoid to power the new fuse block? Is there a better switched 12V source?

In the interest of not adding a second new post:

While I'm doing electrical stuff under the dash, I would also like to add a theft deterrent toggle that will kill power if I have to leave the truck parked away from home - a starter interrupt type system. I would prefer it be accessible from inside the truck and not under the hood. If I put an inline switch on the purple stripe wire will that do it? Or do I need to add the switch to one of the 24V wires to the solenoid instead? If 24V, which wire - red or purple?

Thanks in advance for pointing me in the right direction!

 

[Barrman]

One of the funny looking plugs in the top corner of the fuse box is switched. Put a volt meter on them and see which is switched. The plug that goes in there is a one off design for the rear AC on the Suburbans.

 

[txtriathlete]

Do you think that circuit is robust enough to support 70-80 amps? AC circuits are usually pretty hefty, but i think that might be pushing it.

The reason I want to put in a dedicated switched fuse box is I'm not sure the truck wiring would support the amps to run that many accessories. They won't all run at the same time but I could see having the stereo, seat heaters and aux lights on at the same time.

 

[nyoffroad]

I'd leave the stock system alone and go right off the battery. FUSED OF COURSE!

 

[Barrman]

80 or 90 amps in my mind needs 00 gauge or so wire from the battery to keep it safe and cool. Then use a relay that can handle at least 100 amps continuously to make it switched. Using an empty switched spot in the fuse panel to activate the relay.

 

[txtriathlete]

80 or 90 amps in my mind needs 00 gauge or so wire from the battery to keep it safe and cool. Then use a relay that can handle at least 100 amps continuously to make it switched. Using an empty switched spot in the fuse panel to activate the relay.

I was hoping that the relay under the dash (that I'm replacing) could perform this function - that I could pull a wire off the switched terminal (where the purple stripe is connected) to run the new accessory fuse block. I guess I'm not sure what this relay/solenoid under the dash does? I thought it ran the starter with switched 24V OUT to the starter - so the purple stripe is switched 12V coming IN to activate the solenoid. Am I misunderstanding?

If that lug on the solenoid is 12V coming IN - then I could pull straight off that to run the relay that activates the new fuse block.

 

[WWRD99]

I was hoping that the relay under the dash (that I'm replacing) could perform this function - that I could pull a wire off the switched terminal (where the purple stripe is connected) to run the new accessory fuse block. I guess I'm not sure what this relay/solenoid under the dash does? I thought it ran the starter with switched 24V OUT to the starter - so the purple stripe is switched 12V coming IN to activate the solenoid. Am I misunderstanding?

If that lug on the solenoid is 12V coming IN - then I could pull straight off that to run the relay that activates the new fuse block.

You can use that wire to activate a relay for the block but not to power it...you'd need a dedicated fused line to a deep sea block or something like it with fuses built in it. There's no way that wire will hold that much current. If you can find a rear radio wire set you can run that to the back seat area and use that to power stuff as well and run a relay to the deep sea fuse box to turn it on...just gotta hook it up for 12 volt not 24 unless you are getting 24 volt stuff to run which to me is ideal since everything is better at 24 volts vs 12.

 

[Barrman]

The starter relay under the dash has a ground, 24 volt constant, 24 volt switched to the starter and 12 switched with starter position of the key only to connect the 24 volt stuff.

You need 12 volts switched with just the key on and staying on the entire time the key is on run, not just start.

 

[txtriathlete]

The starter relay under the dash has a ground, 24 volt constant, 24 volt switched to the starter and 12 switched with starter position of the key only to connect the 24 volt stuff.

You need 12 volts switched with just the key on and staying on the entire time the key is on run, not just start.

THIS! This is the exact answer I was looking for thanks. I need to learn how to ask questions correctly.

 

[Mainsail]

Use the wiper circuit fuse to power a relay (and no more) to switch the 12v bus you're adding.