Auxiliary Fuse/Relay box

[Olacmot]

Has anyone wired an auxiliary fuse box in? I am going to put my low beams and high beams on relays, and wanted that to look cleaner than just having two relays hanging somewhere with in line fuses. I also replaced my gauges and don’t have the ammeter any more; the ammeter terminal wires have been spliced together behind the dash. I was planning on doing the ammeter bypass/charge wire off the alternator to the starter relay as well. Plus I have MSD Ignition that needs a fuse, a very wimpy amp for the rear speakers that needs a fuse, and I have an electric fan I want to use a relay for, so I thought this auxiliary fuse box might kill a few birds with one stone.

I plan on leaving the original fuse box in place, my thought was this would be a quick way to add new fused loads without me rewiring the entire car, and reduce load on the bulkhead connector. I have a Tru Mods relay and fuse box, unfortunately it doesn't have a main breaker, so I was going to use it with a positive and negative terminal block, the positive terminal block being fed from a fusible link off the alternator.. I was thinking about mounting it on the passenger side fender near the alternator, but I'm wondering if anyone has put them elsewhere that has worked out well? I've included a picture of the location and a rough diagram of my plan. The direction of the circuits on this diagram aren't necessarily accurate, I just put them where I had space on the picture for clarity. Such as the Battery and Charge wires to the bulkhead connector will most likely be run towards the firewall, not near the radiator. I hope that makes sense.

My rough plan is below. Looking for input if I'm overcomplicating this or missing anything. Or if this is a bad idea in general, stop me now!

- Mount new fuse/relay box, a - terminal block, and a + terminal block. Ground - terminal block to body, + terminal block will feed all fuses in new fuse box.
- Use a #10 fusible link off the alternator battery post, spliced to #6 wire, and terminate this wire on the new + terminal block
- Remove old alternator charging wire from alternator
- Splice old alternator charging wire and battery wire together (#16 and #18 at bulkhead connector), and land on 30A fuse off new fuse block.
- Run new #6 wire from + terminal block to starter relay post.
- Wire from Fuses to relays, and run new wires from relays to headlights...maybe splice into existing harness, but that would make wire lengths longer. Haven't decided.

Questions:
- Should I use a fusible link where the #6 wire from the + terminal block connects to starter relay? This circuit is protected by the alternator's potential by the fusible link between the alternator and + terminal block, but the wire has no protection from battery potential between battery and + terminal block.
- Can I use a fuse instead of a fusible link for the charging wire and battery wire? Factory used a fusible link... is there enough inrush current on lights and interior loads like the radio to need a fusible link? I could splice these two wires together after the factory fusible link if necessary.

I'm curious to know your thoughts, as lots of you have LOADS more experience than I do. Pun intended.

Thanks,

Tom

 

[Challenger RTA]

When doing an amp meter bypass As what it is referred to. The amp meter can be left intact. It just won't function as it should. A voltage gauge can be used to monitor state of charge.

The only thing in my opinion is that the current from the alternator is not fused that feeds the load to splice one. . A fuse-able link or a breaker from the alternator. that would resolve that issue. The diodes would probably blow out before any damage would happen? Why take a chance.

1.option A way to bypass the ammeter. Considering that the original wiring is in good condition. Load feed still coming from alternator through connector 18 to splice. Connecting to thesis points would be electrically the same. using a 6 or 8ga wire to charge the battery. Directly to the battery + terminal, to the starter relay that connects directly to the battery or on the starter terminal. Therefor it can be concealed alongside the engine harness.

2, option Removing damaged wire 18 and A1-12R.The problem with removing them is there is no connection to feed the load splice one and no charging of the battery. A charging bypass would resolve the charging.
The other would to be an alternative routing for both R6 12BK wire 18 and A1-12R to the amp gauge of 10GA or 8GA. An option would be to go through the wiper washer foot pump grommet.
.
3, option This is what I did. A charging bypass. An other opinion would be to connect the alternator to the Battery with a fuse-able link or breaker. To use feed the alt baulk head connector. Cut R6 from splice one and feed to the acc side of fuse box. Then there are two 20-25 amp circuits on a fusible link. I also cut headlight circuit from splice one and fused through fuse box. Note headlight circuit need not be cut if so not desired.

4 option The only thing that is not fused yet the wiper motor from splice 3 Might piggy back on acc side fuse box or do an inline fuse, or add a small fuse box using one of the disconnected ammeter wires. I can't do that I cut them they were in bad shape! Keep it in mind. If in good condition reroute load wire R6 12BK to feed aux fuse box and then to amp gauge.

5 option 4 ways to horn power connection. Document fusing and keep in glove box for reference.
This is What I did or will do and feel comfortable with. your choice if you do it or not. Document fusing and keep in glove box for reference.


2 continue, As I said earlier about removing the high current load from the problem components (bulkhead connectors). I ran a one 6 GA wire to the alternator to battery ,removed the headlight power from splice one and fused it in the fuse box and a relay circuit. Changed 4 way feed to the horn fuse. Installed a voltage garage and removed the red and black wire to the amp gauge. The voltage gauge can pick up power and ground on the cluster. Voltage limiter or amp gauge wires. They were bad! That brings on an issue that requires an alternate wiring for accessories. Used the alternator feed bulkhead connector #18. From the battery with a fuse able link to #18 to feed the accessory side. So in essences there 2 feeds feeding the load. There are two other high current loads. 1 the heater fan 2 the rear defroster if there is one installed. Power windows are a whole other thing. This is just a brief description of what I did. So Don't do it the information is not complete it's just a summery.

When motor is not running power is supplied by battery. Travels from battery to bulkhead connector 16 to red wire A 12R to amp meter. Follow the blue and yellow dots. Then to 12Bk to splice one. This is where it feeds all the loads or circuits. The headlights are feed from splice 1 through the Black wire white tracer. Q3 12R One red wire from splice one feed the battery side of the fuse box. J1 12R The other red wire feeds the ignition sw. Follow yellow dots. The Black wire R6 12BK Blue dots comes from the alternator. It supplies power for the load and charging the battery. BE AWARE! When the key is not on there is power the alt terminal.

 

[Challenger RTA]

Put an old full size battery in. To show that a 6 circuit power relay center fits in front of it. It is feed from a breaker connected to the battery or the starter relay. One relay feeds the low and the other feeds the high beams.
I did put a 4 circuit fuse box under the dash. It can be feeds from the fuse box BATT terminal or starter relay. I did retain the the feed through the bulkhead connectors. As I repaired and reduce the current through them.
As in your case you can do the same or feed through the washer pump grommet.
Also in you case you can feed you ac fan from the relay box. Reducing more of a load though the bulkhead connectors.
In any event be sure to have a an adequate feed where ever you are connecting the loads.
That binging said for example: Alternator bypass connected to the battery and connect all loads there. Alternator bypass connected to the starter cable connection or starter relay and connect all loads there. The reason being, The feed to relay for the starter solenoid my not be rated for that kind on load.

Universal 6-Way Fuse Box Relay With 6 Relays Fuse Holder 12V Car Truck ATO/ATC A | eBay

 

[Katfish]

I wouldn't over complicate it, easy to hide the relays.
I put them under battery tray, out of sight.

https://postimages.org/][/url]

 

[Olacmot]

Put an old full size battery in. To show that a 6 circuit power relay center fits in front of it. It is feed from a breaker connected to the battery or the starter relay. One relay feeds the low and the other feeds the high beams.
I did put a 4 circuit fuse box under the dash. It can be feeds from the fuse box BATT terminal or starter relay. I did retain the the feed through the bulkhead connectors. As I repaired and reduce the current through them.
As in your case you can do the same or feed through the washer pump grommet.
Also in you case you can feed you ac fan from the relay box. Reducing more of a load though the bulkhead connectors.
In any event be sure to have a an adequate feed where ever you are connecting the loads.
That binging said for example: Alternator bypass connected to the battery and connect all loads there. Alternator bypass connected to the starter cable connection or starter relay and connect all loads there. The reason being, The feed to relay for the starter solenoid my not be rated for that kind on load.

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Thanks. I looked at putting it here but one of the AC hoses seemed to be in the way. I’ll take a second look, or maybe put it on the other side of the battery.

And by feed to the starter solenoid post, you mean the wire from the battery to that post? Mine looks to have been replaced and is #10. I plan on up sizing that wire too. Good call.

 

[Challenger RTA]

Thanks. I looked at putting it here but one of the AC hoses seemed to be in the way. I’ll take a second look, or maybe put it on the other side of the battery.

And by feed to the starter solenoid post, you mean the wire from the battery to that post? Mine looks to have been replaced and is #10. I plan on up sizing that wire too. Good call.

How did things work out for you. The AC is something I failed to take in account. 1 Some would have opted the connect the ALT feed to the starter battery feed. I like this one the best. That is a good place because it would handle the load either way. There might be issues for other that might have headers or other in the way. 2 As far as the starter relay connection it might be ok if there is not that much load. But why take a chance upsize the gauge or put it where it will not be an issue. It's a shot run! 3 I opted to go to the battery terminal instead of the starter itself just for simplicity. I think I will change it to the starter battery feed at some point.

 

[Olacmot]

How did things work out for you. The AC is something I failed to take in account. 1 Some would have opted the connect the ALT feed to the starter battery feed. I like this one the best. That is a good place because it would handle the load either way. There might be issues for other that might have headers or other in the way. 2 As far as the starter relay connection it might be ok if there is not that much load. But why take a chance upsize the gauge or put it where it will not be an issue. It's a shot run! 3 I opted to go to the battery terminal instead of the starter itself just for simplicity. I think I will change it to the starter battery feed at some point.

Timely post on your part! Did the universe let you know I was working on my car this morning?

I haven’t gotten to the fuse box yet. I bought a 100A CVS racing 1 wire alternator and did that upgrade this morning. I just taped off the old charge wire for now and ran a new #6 wire to the starter solenoid. I’m working on upsizing the alternator ground to #6 as well right now (posting that if keen eyes note the wire size in this pic ).

I double checked room in front of the battery for the aux fuse panel and I think I can make it fit there per your suggestion after all.

As for what to do with the old charge cable… I think I am going to remove it from the harness it is in, re route it to the drivers side of the engine, and splice it to the red #10 wire that goes to position 16 in the bulkhead connector. Attached is a picture of where I’ll do that, downstream of the fusible link. I’ll upsize the charge wire to #10 and replace the old #10 red wire “A1C-10R” so they’re similar lengths and wire type to the bulkhead. Probably overkill, especially once the headlights are on relays. Let me know your thoughts.

Last note: to weatherproof the 2 wires to 1 wire splice under the hood, I was going to use liquid electrical tape under heat shrink. If you have a better/cleaner way to do it, let me know!

 

[Challenger RTA]

I double checked room in front of the battery for the aux fuse panel and I think I can make it fit there per your suggestion after all.

That's good. It's a good location for accessibility and convenience of everything in one place. It's better then locating everything elsewhere. But one has to do what one has to do.

As for what to do with the old charge cable…

I think you have pretty good understanding of what your doing and removing the high current loads from the problem areas. As far as the original charge cable being removed it originally feeds the loads. That is splice one under the dash. Splice one I never see an issue with it. I would never touch it! If it is good under the dash I would pick it up from there and use it. Or you can connect to the back of the Amp gauge for a good connection. You eliminated a lot of load through the bulkhead connect by doing what you did. 10 GA would be good just depends on being able to get into place. To do the ALT bypass with a 6GA that is one thing. It is all pretty well working by itself. To run a other feed to make up for the charging circuit and it feed the loads that was removed. That is an other thing. I would use the same gauge wire that was original. But feed it from the same fusible link. If you run a 10GA for charging and load side. Then do the same for the feed from the battery to the fuse box. I did run an other feed using the original charging and load through the bulkhead connector. They both have there own fusible link. But then I split the fuse box load. Battery feed side AUX feed side. I also put an AUX fuse box under the dash for alarm, trunk release and other. Loads that need constant power. That is a little more involved but not too much more. It is fused from the aux relay, fuse box by the battery.

Last note: to weatherproof the 2 wires to 1 wire splice under the hood

Elaborate on this so I know where and what you want to splice.

 

[Challenger RTA]

Timely post on your part! Did the universe let you know I was working on my car this morning?

Yeah the MOPAR Gods have control of this site.