Where to pass electrical through firewall?

[Corbet]

Working on wiring some new lights. I need a 1" hole to pass electrical through. I've already used the OEM clutch hole on the driver's side as well as the Main ECU harness hole on the passenger side behind the glovebox.

I'm willing to run a hole saw. But an OEM hole would be preferable. Any ideas?

 

[mmajsw]

If you are running a bunch of smaller wires, you can use the radio antenna grommet.
If you need a 1" home for a 1" item, you gotta drill or repurpose an existing hole. I.e. move wires from one hole to another to make space in the existing hole.

 

[LINUS]

It’s going to be more work but I’d disconnect whatever is passed thru the clutch hole, and enlarge it.

Also, Ford’s rubber plugs for circular holes (edge protection) -are really well made, almost as nice as marine application plugs from West Marine, or similar boat-part vendors. I pick up Ford ones whenever I hit a picker yard local to me.

Finished result means a cleaner overall harness & no “Swiss cheese”-ing the firewall.

Save the Swiss for a ham samich.

 

[Corbet]

I’m leaning towards re-wiring and enlarging. While fighting the impatience of wanting the new lights functional.

Might have to save for this. SP-9100 Bezel Style 8-Switch Panel Power System with Concealed Mounting Hardware

While the wiring harness I was supplied from BajaDesigns seems of very good quality. It feels to me it’s clearly designed for a race chassis. Its design is not firewall pass through friendly, nor are the circuit runs of the right length for under hood install.

Installing my 2nd battery I could move my main accessory power to the passenger side and free up the clutch hole for switch wire routing. Enlarge if required. Have battery and tray. Need charge controller and wiring.

Who needs a barrier? Need parts funding.

Teaser photo of the lights.

 

[McDowra]

I used Universal 6-Switch Power System might want to look at it no need to cut big holes just a small slit in clutch plug

 

[White Stripe]

What exactly are u running that u need so many wires going through the firewall? Maybe look carefully at how your wiring auxiliary systems and see how u can lessen the amount of wires.

 

[Corbet]

Currently run through Firewall

HAM Antenna
CB antenna
Trailer Contoller
Main 12v accessory line to interior fuse block.

The main line is 6AWG and heavily insulated. It almost consumes the clutch hole on its own

 

[White Stripe]

Maybe extend your current main wire firewall hole from a round to a oval...
Mustang PCM Harness Firewall Grommet (83-04) - LMR.com

 

[Corbet]

I think the Switch-Pro’s is really the most logical solution. It solves this plus gives me 5 more circuits pre-wired for future mods. Back-up, extra cooling fan, rock or scene lighting?

It’s just cost and time against me right now. We leave for Yellowstone in 4 weeks and I’d like to have a solution even if only temporary but safe/reliable by then.

I tired to pass the two light connectors through a 1” hole grommet and can’t get the first through. So even cutting a new hole next to the clutch hole does not get the harness out if connected to the interior fuse block as it’s power source.

If I go the other direction I can get the switch feed through the grommet but the line is pretty short. I’d have to make the firewall at the brake booster the mounting point for the relay and feed power direct off the battery. Have not measured but the switch feed should make it up to one of the dash blanks by the locker switch.

 

[Rifleman]

Corbet, just a question, but with your winch, and now those big lights blocking most of your grill opening, do you think that will have much of an impact on your cooling this summer?

 

[Qball]

where is this clutch hole everyone is talking about? Any pictures? Is it right by the brake pedal?

 

[Corbet]

Corbet, just a question, but with your winch, and now those big lights blocking most of your grill opening, do you think that will have much of an impact on your cooling this summer?

Yes and no. I had a set of IPF lights nearly as big before without issue. But I do plan to relocate my winch solenoid box for this very reason. I'll build a new bracket and get it down behind the main plate portion of the bumper.

where is this clutch hole everyone is talking about? Any pictures? Is it right by the brake pedal?

If looking from the engine bay its just to the right of the brake booster. If inside the truck simply imagine where the top of a clutch pedal would be to the left of the brake pedal. There is a big grommet blocking the hole. And from memory that part is long discontinued. So don't loose that grommet.

 

[Corbet]

So last night I committed to a new hole to the right (left in engine bay photo) of the clutch hole. I ran the switch circuit through and mounted the relay to the top of the fire wall. The main power direct to the battery and the harness to the lights along the firewall and the passenger side of the engine bay. Even with that long run I had about 18” of extra harness to the lights. Also a bunch of extra to the battery that I’ll eventually cut once I decide on a distribution block to get the wires off the battery posts.

I also need to decide where to put the switch. It will probably come down to depth behind what ever blank. Right now the far left below the HVAC controls in the dash or one of the center console change holders are my two most desirable locations.

Finally I need to tap into an ignition hot circuit to power the DRL feature. I’ll probally do that at the fuse/relay box behind the battery.

Final photo is low beam + DRL

pics.

 

[inkpot]

where is this clutch hole everyone is talking about? Any pictures? Is it right by the brake pedal?

Here!

 

[Qball]

View attachment 1712834

Here!

Thanks! I already use that hole except I didn’t know it’s called the clutch hole.

 

[inkpot]

Thanks! I already use that hole except I didn’t know it’s called the clutch hole.

Look at the depressions for the 4 mounting bolts and the center ring.

 

[LandCruisinMy93]

There is a grommet on both sides of the firewall about 3" diameter they're by the fender wells and have a center hole and then 2 little murders, one on either side. I utilized those for re-running wiring when I installed my clutch. I didn't have that many wires and none were large gauge so I just sliced an X on the end of and popped wires through. I pulled the wiring back about an inch and taped them on the inside then put some FIPG in the hole and pulled the taped portion into it to make a seal.