Electrical/Wiring/Fuse question. Just to be sure itÂ’s safe!!

[Cndnmax]

No but for the AMP. If its a 10 A fuse I can’t put a higher one for the new circuit am I right?

Generally speaking they would be two independent circuits. The limiting factor would be the wire feeding the fuse, it has to be sized to support both fused circuits. So a 30amp new circuit from a 5 amp original circuit might not be wise.

Although, all you’re feeding a very low draw relay. Don’t over think it, keep the 5 amp fuse and the ordinal 30amp circuit u had before. Just go through the steps to make sure it’s properly installed.

 

[WD_T4R]

So I finally found an ignition empty fuse slot. I put back the original 30a wiper fuse in place.

I put only ONE 5a fuse in the add a fuse (put it in the « new circuit slot » like the picture rigtec showed me). Is only one ok in the add a fuse?

So I test it by blowing the horn and it blew. I put a 7.5a one and test it again. Was ok.

Now I have a Add a fuse with one 7.5A fuse into a 12v ignition fuse slot that was empty.

I think I should be ok? What are you guys thinking?

Btw a big thank you to everyone helping me out. Very appreciated!!

 

[rigtec]

Hi WD_T4R,

"A typical 12V relay coil consumes less than 0.2A for the switch circuit. The load-side (the contacts) are rated on the relay nomenclature tag e.g., 30A, 40A, 50A...etc, so the relay is sized accordingly, based on the current draw of the device being installed!..."

Just to clarify my above post... A typical (Automobile 12V) relay coil circuit draws less than 0.2A, so keep your fuse size as small as needed to protect the truck's wiring! There's no need to use a large (7.5A, 10A...etc) fuse in the D/S fusebox cuz that fuse has 'nothing to do with the compressor or Air-Horn' circuit! The fuse for that circuit should be an 'In-line fuse' under the hood and sized to protect the device installed!

rig

 

[rigtec]

WD_T4R'

Since you PM'd me, I've been thinking...

There's a very simple way to accomplish this task using one 'AOB' dash switch, and one SPDT Relay if you're interested(?)! Since an AOB switch was mentioned, I thought to include it in my control scheme. You'd use the AOB switch only to choose which horn you'd want to use and when. With the flip of the switch, you can select the appropriate mode. I Drew/copied the stock wiring diagram below, and added the AOB switch and one relay: Here's how it will work, Click the ENLARGE button to view more details:



You would still use ONLY the factory steering wheel horn button (^^in the circle drawn above^^), but for either the factory horn, or the "Air-Horn"; which is simply selected by the AOB switch! Using the SPDT (single pole, double through) relay, the horn of choice is selected. No wire cutting is needed. The HOT wire on the horn(s) is moved to the SPDT relay contacts terminal, and that's how the horn swapping is achieved!

When the AOB selector switch is in the OFF position, the stock horn will operate. When the AOB switch is in the ON position, the AIR HORN will operate. And because you're feeding the switch from the driver-side fusebox, the SPDT relay will remain OFF until the vehicle is turned on with the key/push-button, follow...! Don't let the wiring diagram scare you!

You're NOT changing any of the factory wiring or tampering with any of the stock electrical components. You only need to remove one wire off of the horn sounder under the hood (in front of the radiator). Place it on the new relay terminal #30 and reconnect term #87A (normally closed) to the horns. Then connect term #87 (normally opened) to the AIR-HORN valve, that's it!

I hope this will simplify the install, and also make it more convenient to use, 'Best to you',

rig

 

[rigtec]

...It just occurred to me,

I recently noticed that I'm not getting any member notifications e.g., PM's, Likes, Mentions, New post on subscribed threads...etc, on the t4r notification box at the top of page! As a result, I've missed some relative posts on this thread. So if I don't reply within a reasonable amount of time, that's the reason! Also, has anyone else noticed that there's no 'Upload button' in your photo album page?

There is still an upload button after clicking the 'Attachments' icon, but I never use that option of adding a photo to a thread because you can't choose the placement of the photo relative to the post dialog structure! I typically Copy/Paste a "Photo-bucket" URL as I've done in my last two posts in this thread! So [MENTION=222848]Cndnmax[/MENTION] is certainly qualified to read/interpret the sketched wiring diagram that I've posted above!

Oh, almost forgot to mention: The Air Compressor can Still be controlled by the wiring harness, relay and switch provided in the kit, or an additional AOB switch in the dash may be used; there are Three available blank-offs in the dash for Toyota (unavailable) options! 'Best'

rig, cheers!

 

[4Reak Show]

I don’t see a wiring diagram. So I can not give advise if it’s wired correctly. What you want to do is control the coil voltage to close the relay allowing typically higher voltage/load across the switch powering the device. Relay coils are typically low voltage but any circuits needs short-circuit protection. Including the high voltage side. 30 amp fuse in the box labeled wiper means the total sum of amp draw on that circuit dictates a 30 amp fuse. Relays are used because of high load on contact points when opened (tuned off). A wiper “motor” has a high amp draw and inrush when first started. You might get away with a lower amp draw fuse for a while, until any real load is applied at start up( wipers frozen to the windshield). The real issue is if you replace a smaller fuse with a larger fuse(replacing a 30 fuse with a 50amp that’s on hand), this allows more current and time to burn electronics including the wire. If you can post a pic of the diagram, I can walk you through. The main part of my career is figuring out electrical control issues within complex often proprietary equipment, meaning the diagram is unavailable but I’m there...ultimately You popped a 5amp fuse because you sent close to 30 amps across it.

Hecka smart