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Rewiring fuse block

Weasel

Weasel

Red Skull Member
Joined
May 20, 2020
Member Number
712
Messages
2,696
Loc
Black Hills, SoDak
So been having an issue with my fuel wiring the past few summers, 3/4 through an all day run the jeep would start running really rough. Real similar to vapor lock. Finally chased it down to the fuel pump not getting constant power after running for several hours. Started working back through the system and think I found a bad relay so replaced them with new units.

Working on it a bit more tonight and found a fuse that must have shorted and blew. In looking at the fuse block I'm tempted to replace it with a unit that have the bigger Jcase fuses.

This is the existing fuse block:

1712983320488.png


I lost the cover so they are exposed to the elements, could stick in in a bag or similar but considering replacing it with this:

1712983575706.png


The are a couple issues:

#1 - I'm going from 4 fuses to 2. 2 of the fuses are 15 amp and the other 2 are both 10 amp. So it seems like I could consilate the 2 sets into a 10 amp side and a 15 amp side. All are 12v and the current draw should be fine with the JCase fuses
#2 - the biggest issue I think - All of the fuses are current hot on one side other then the Coil & ICM. So what am I going to screw up by putting the Coil and ICM on a constant hot fuse connection?

Well they would be hot when I flip the switch to power up the Jeep.
 
Correction, the upper 3 are powered when the run switch is off, when I turn the run switch on the lower Coil and IC have 12 volt hot as well.

So it would seem I could swap with no issue and either run a single run switched power or constant as soon as the battery is switched on with no issues?
 
maybe, we ran a single hot wire to the pump and it ran great, similar sized to what I wired with it originally. I think it's a bad relay but need to do some more testing. I think I ran 14 gauge to the fuel pump.
 
Weasel said:
maybe, we ran a single hot wire to the pump and it ran great, similar sized to what I wired with it originally. I think it's a bad relay but need to do some more testing. I think I ran 14 gauge to the fuel pump.
Click to expand...

needs to be 10g minimum from battery to pump
 
Hmm yeah that pumps says 12amp. So it's under fused anyways. Will have to check into that and them wire size as well. Thanks for mentioning that item.
 
Weasel said:
maybe, we ran a single hot wire to the pump and it ran great, similar sized to what I wired with it originally. I think it's a bad relay but need to do some more testing. I think I ran 14 gauge to the fuel pump.
Click to expand...

How/where is the pump grounded, and what is the condition of the ground lead's termination like? Might be worth checking that as well.
 
the ground is a bolt welded to the inside of the frame/slider. Pretty sure it's good. New plan is going to be using the computer signal to activate a heavier duty relay with the correct wire size to feed the pump, vs using the painless wiring to feed the pump. It's 2 switches but should fix the draw issue. And if that ever goes kaput I can easily move the pump a hot feed.
 
mobil1syn said:
dont undersize the ground either, i always just match the size but im sure Bebop has a more ‘educated’ way to do it
Click to expand...
Totally fine.

Weasel said:
the ground is a bolt welded to the inside of the frame/slider. Pretty sure it's good. New plan is going to be using the computer signal to activate a heavier duty relay with the correct wire size to feed the pump, vs using the painless wiring to feed the pump. It's 2 switches but should fix the draw issue. And if that ever goes kaput I can easily move the pump a hot feed.
Click to expand...
I would have changed that shitty fuse box instead. Your problems come from that part first and foremost.
 
If you're looking for a new fuse box, I like the Chief ones because they're highly configurable for specific purposes. BRIC® Fusion Bases | PDM | Chief Enterprises

Might be kinda overwhelming though.

The Eaton RTMR series (bussed versions) are great too. Can often be picked up for cheap on eBay. Blue Sea ST blade fuse blocks are also nice and easy to work with, provided, you're locating your relays elsewhere. The other options all integrate relay sockets into their design, but also require you to crimp Metri-pack 280 or Bosch terminals.
 
Bebop said:
Totally fine.


I would have changed that shitty fuse box instead. Your problems come from that part first and foremost.
Click to expand...
Maybe but seems a solenoid was going bad when it was hot. It never quit running just ran like crap. I understand what you mean though.

I only need these 4 fuses but can look at a full replacement of some sort.

I wish Eaton would make the unit above with more fused cavities and with duestch connectors.
 
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