Can I please get some feedback on my wiring layout?

Sal R.

Active member
layout.jpg

Thanks for looking!

I know basic wiring and whatnot, but no expert by any means. Feedback would be greatly appreciated.

The idea is to make adding new accessory circuits easy via relay, minimize wire runs into the cab, and have most, if not all, accessories powered by a relay.

I added the 100A ignition relay so that all my accessories are enabled only when the car is "on" to prevent battery drain.

I never had to add too many accessories in any of my cars before, but I'm hoping that this layout will accommodate growth as my needs change. This is the most extensive wiring modification I've undertaken.

Near term implementations are heavy duty air compressor and locker switches.
 
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dwh

Tail-End Charlie
Um, feedback...

Well first, ignition relays are not usually rated for continuous use. See the $50 isolator thread for a more appropriate type of relay to use between battery and fuse box.

Second, I think switching the entire fuse box on and off via ignition controlled relay is A) redundant, and B) probably not a great idea.

A) Since you are already planning to switch branch circuits via relay, there is no need to switch off the fuse box as well.

B) You might want to have a circuit remain hot even with the ignition off. A fridge for example.
 

WyoCherokee

Adventurer
I would leave your fuse box hot, and have a dedicated switch relay for each accessory. As dwh said, you want your fridge to stay on, even when the ignition is off.
 

krick3tt

Adventurer
I use a second (integrated into the system through a battery isolator/charger) battery and a Blue Sea fused box to take all my aux items from. That way I can have the ARB on all the time and each additional item is fused and separately switched.
 

Dillon

dome light
Depending on where you mount your fuse box, you may want to put a fuse/circuit breaker in the circuit between the battery and the fuse box. As was suggested above, don't switch the fuse box, wire each of your power circuit relay 85 terminals directly to power for always on or through the ignition circuit for switched on.
 

Sal R.

Active member
Thanks for all feedback.

Definitely going to keep the fuse box hot and move the ignition relay to the switch side.

Instead of a 100A relay, ill install a circuit breaker instead.

No plans for a second battery at this point. For what I use it for, it's a bit much and I don't want the added weight.
 

paranoid56

Adventurer
I would say ditch the bluesea fuse box setup and get the bussmann one as it has relays build in along with extra fuses.

myself, i want with a 80amp power relay that powers the bussmann relay panel. I only wanted this panel powered when the ign is on (will have a secondary battery setup for the frige)
This power relay also has replaceable fuses so i am covered there.

CWVOE29hJ-oMqAWRNt1vApP21-p5DmYjJp8DShCmd0oPG9nkqvoEf8M8DQnYRc0vKkUExkF4wjrLesUheHh7eAQ2ESn2oSXKBaOG96TosAmMhcjJ9_HUms0o8AJvW1ox2JPHLALH-ox6mGUO0OhUhWKEMiMpb0mzL7tp6eOWZ2RyOZk42IfIfa7GJiRVPq4-gnDLn5UshcofJ4d7u5aawHLSV2VfojL5-rt7ChUulJ1G_62Qqf-hcMMPjleqm58mW3-lMqurEKwq6yYVlJBBT1PrArQb5jR0Hs5U3mA-jPx_2qkrkEBJRlPIhFHyYzoYGGHHzVhJNq_bJgufLSJmBAY2jXJwfvd1MjjZKWcAE-4EtvmSjjT4zbRiNy0D1XmpPQWLIwqZM0fC3ZX5eG8wItwhHeCgvHIYVa9NBJmZ2Cy1P05iqfiNJKOKtcMDQj8hq3eE6NC6iHQwHji_mSOWJsWOkPhHQ7KCAwNda28ubJjwBvxezTbKHbhysqZ6sBQNVPx5blF3spf92JAXsLAAlpYZn99e8mbTXrahqJleYBwtFBhyHJ94fGtowEXt1TJVpRvB-zubkyjsj_rP6X4ImacSUqbyw8vITWL73DIdrKYEa8rWRHMsjvNOtm9N7UfNwhO-8TSdsIRFo0xNLFCp6LVwQ_B0YRwn9tEV=w541-h721-no
 

Sal R.

Active member
I would say ditch the bluesea fuse box setup and get the bussmann one as it has relays build in along with extra fuses.

myself, i want with a 80amp power relay that powers the bussmann relay panel. I only wanted this panel powered when the ign is on (will have a secondary battery setup for the frige)
This power relay also has replaceable fuses so i am covered there.

Aww man...didn't even know they made those. And just got done mounting and powering up the power tray and aux relay box.

I guess it's not too late to turn back...

powertray01.jpg
 

Sal R.

Active member
So here's my general switch layout:

wiring-general.jpg

Tested the circuit using a generic 3-pin illuminated rocker switch I had handy in my toolbox.

For the most part, it works. The associated relay energizes and switches contact between 87a & 87 providing power to the associated accessory.

However, the switch won't illuminate in the "on" position. I assume the 5-pin OTRATTW switches will function the same way.

Can anyone shed some light (no pun intended) as to "why" the switch doesn't light up?

Screenshot 2017-04-23 22.45.47.jpg
 

Sal R.

Active member
So, its not lighting up because there's no power being supplied to the "on" LED when the switch circuit is completed. As a result, changed things up a bit. Changed pin 85 in the engine compartment relay to ground, removed the cab ignition relay to feed ignition 12v and connected to switch pin 2.

I think this would be okay. The power draw is low. Really only used to illuminate the "on" LED and energize relays.
 

Sal R.

Active member
Just be sure the conductor from your cab switch to engine compartment relay will carry the max fault current of whatever "12v ignition" source is fused at.
Btw,
Your prior scheme was one regard safer in the event shortcircuit on cab to engine compartment conductor.
Shorting that conductor to chassis would simply turn on its associated relay, Nothing would melt, No fuse blow, etc.

I would have preferred the switch to ground. It only made sense (to me), but i could not find a working solution to illuminate the LED "on" position. If you have any recommendations, I'd love to hear it.

Each conductive switch wire is 16ga over a run of about <4ft. I'm going to try and tap a similar gauge with an 1A inline fuse since the switch draw "should" be minimal.
 
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