Technical Does the fuse box need to be inside the cabin? Building my '49 F-47

Hi guys,

I am getting ready for the winter building months and want to start gathering parts for the wiring I will be installing, all from scratch. I am planning on a few non HAMB add on extras so I will need some relays and probably 12-52 ccts. I have selected the fuse panel and was thinking tonight, why is the fuse panel usually inside the cab? Probably the new cars have more stuff in the cabin than outside, and there is quite often a separate panel under the hood for engine and high power ccts. So for a reasonably simple wiring job, I thought it might make more sense to put the panel under the hood on the firewall, in a weatherproof box, then just run the needed wires thru the firewall for gauges, switches etc, and the rest remain under the hood to go the rear and front end for lights etc..

Look forward to hearing from the brain trust, on benefits of either location.

Cheers!

 

In today’s world there are many waterproof fuse boxes especially if you look in Marine applications and that makes your choices easier.

 

Just make sure it's actually sealed and beware of condensation. Corrosion in a fuse panel can be a disaster.

 

If it is in a sealed box, it will be fine.

A whole lot of OEM fuse/relay boxes are under the hood. I have yet to see a sealed one. They all just have a simple cover.

 

Most put it under the dashboard for the simple reason they are not attractive. If you do not mind the look under the hood is fine, just makes the engine compartment a bit busy looking.

 

Agree with all of the above. Look at all of the newer cars out of Detroit, plus the Asian cars.
They typically have at least two fuse and relay boxes mounted in the engine compartment, but sealed
very well.

 

Thanks guys, appreciate the help.

I will search for weatherproof box for it. I was planning to mount it on a shelf above the MC as there is lots of room there and access is great. There is already a 1.5" hole thru the firewall right there. I still could put it in the cab but there is so much bracketry and bracing under the dash for the hanging brake pedal and 70's GM steering column, that it would have to go above the trans hump. I'll keep both options in my head for now. The fuse panel is due to arrive today, i'll post pics tonight.

Cheers

 

Think about a cold, windy, rainy day - now select your fuse box location.

 

Beats standing on your head, looking for a fuses.

 

Most modern under hood fuse boxes may be water resistant , but hardly dust & moisture proof .. Under hood engine temperatures do help keep them dry , IMO .

 

I rewired two car's and put the fuse panels in the trunks. Very easy to get to and out of the way. Also put the battery's in the trunk's.

 

I've never seen a truly "sealed" fuse box under the hood. They have covers, sure, but all had vents and drains to allow moisture to escape.

I mounted the fuse box and the battery in my Chrysler under the catwalk between the trunk lid and the rear window. I like it because it stays cool and dry there, and it's much easier to access than folding myself under the dashboard with a flashlight. And I don't have to look at them when I open the hood.

 

I would advise against hood louvers

 

The late model underhood stuff has possibilities, the one in my Exploder has relays and the larger fuses, but the one in the Powerstroke has relays, large and small fuses, would probably work for all hot rod circuits but is not huge. BTW, when I hook the laptop scanner to the PSD, it says there are 492 sensors- and it's an '01..

 

Actually I think the closer to the battery is a better place for fuses...A safety thing...

 

If I had it to do over, under the hood it would be. Looks be damned.

Ben

 

Many new cars put the "fuse box" wherever they need it to prevent electrical interference because of the computer communication circuits and to optimize the wire harness and wire size requirements. The under hood "fuse box" on a late model Ram truck is called a power distribution center and is actually a computer that controls many of the functions of the truck like headlights and cooling fans. On the Charger and Chrysler 300 the battery in in the trunk and the power distribution center is in the trunk next to the battery. You will also find under dash and under hood fuse blocks on the same cars. Mount the under hood fuse box as high as possible in case you run through a deep puddle at speed, make sure it has some kind of cover, and it should be good to go.

 

When I rewired my '39 p/u with a Rebel 9+3 kit I mounted the fuse block under the dash. Turned out to be a mistake. I had a flasher take a dump and it was next to impossible to stab the new one into the slots in the block since the block was way up under the dash and impossible to see it clearly. I'm getting ready to use the same kit in my Ranch Wagon. This time I'm mounting it in the engine compartment in a box. Driver's side up front on the inner fender well.

 

Those under-hood panels are generally for specific high-current circuits and are mounted where they are to shorten circuit lengths (reducing wire sizes and saving the OEMs money), and lack of under-dash space/accessibility. They also have limited numbers of circuits that are controlled with their included relays, adding complexity that probably isn't desired in this case. The majority of (if not all) vehicles still have their 'main' fuse panel/panels located in the interior space somewhere as that reduces their exposure to environmental hazards.

 

The Chevy LUV pickups had the fuse block on the inner fender well, it had a plastic cover, but it wasn’t waterproof. It was a popular fuse block to use on other stuff, I’ve got one in my 31.

 

How many circuits?

 

Somewhere between 12 and 52.

 

Ooops a senior typing moment..I meant 12-15 circuits, and probably 4 or 5 relays.

I just got home with the new "power distribution center" and will post pictures shortly. Currently planning on a box mounted above the MC, set horizontally, right near the 1.5" pass thru hole in the firewall and only 3' from the start solenoid and large 5 terminal main power block.

Thank you for all of the great ideas and suggestions....more soon.

Cheers

 

Well this is just too damn cool not to post before dinner...I am impressed. It has 4 micro relays, 4 regular "Bosch" type relays and I think 17 or so full size blade fuses, ones us old guys can pull out and read without a magnifier. I'll post make and model numbers etc later....came from Digikey, $130 CDN about $100USD. Off the shelf TE connectors, again Digikey and mounted on the back, you can populate only the ccts you want to use and leave the rest empty, very cool. It's about 4x8".

Cheers

 

Digikey has good stuff.

 

You only have to worry about fuses getting wet if you drive in the rain.

 

Mine is mounted on the firewall in an old sprinkler timer box! Getting too old to crawl under the dash.

 

I got a late model that has several fuse panels. They are everywhere. LOL

I do not like the idea of under the hood. if you are going wiring crazy put the panel under the seat and run everything under the car and join the harness to the panel via plug like the factory does.

 

For what it’s worth, Ron Francis recommends putting it on the kick panel driver side. You want to get to them quickly IMHO

 

Oh, I like that idea...I'll see how much room there is in there tonight, I still have the stock E-brake pull handle in that area, if I recess the panel and there is room for the wires to exit...may just work.

Thanks!