nagata

I'm going to be installing aftermarket seat heaters in my 08. Does anyone know of a good place to tap into a high current power source inside the cab? Can a new line be run out of the fuse box? What about a good place to bring a new power line in from the engine bay to the cab?

On previous vehicles when I've needed accessory power for some addition, I was always able to bring a new power cable through a small gromet or opening in the firewall, but I haven't found such a place in the F-150s firewall. I'm not too thrilled about the prospect of drilling through the firewall, so I'm hoping to avoid that.

I'm also going to be installing aftermarket foglights, so I'm looking for a good method of wiring those to the interior switch as well. Thanks!

nagata

Alright, I'm an idiot, there's a large gromet in the driver side firewall, near the gas and brake pedals. I'd seen it before, just forgot about it. However, that's not exactly a great place to have wiring running around.

After thinking about it a little bit and a quick Google search, I realized this should be relatively easily, as I should be able to get a mini-fuse tap to plug into one of the unused circuits in the fuse box. Just a matter of finding one that's vacant, energized by the ignition, and can handle the load. Anyone have experience with doing this? Still able to put the fuse box cover back on?

Still trying to figure out a way around running new wiring into the cab for the fog lights, but not have them solely linked to the parking lights or headlights.

ATOM

most of the unused circuits are empty and not connected. if it were me, i would just tap into a keyed accessory so they could never accidentally be left on.

as for the fog light question, you can always use a relay and tap into the headlight harness, only downfall to that is the fogs would always be on with the headlights.

dplummer87

I used a 3 way switch to run my off road lights and tapped into the High beams and the fogs. This way I have a toggle switch inside to where my Off road lights are eith On with the Fogs - Off - On with the high beams. I ran it through the gromet on the driver side fire wall.

nagata

I definitely want to use a keyed line for power, because, as you say, don't want the heaters being left on. Problem is, I don't want to overload a circuit (like the radio, since that's an easy one) trying to run 2 new seat heaters on it. Gonna bust out the voltmeter and see if I can find anything usable in the fuse box.

They're Hella fogs on a relay system (I always use relays, had a near miss incident with direct wired fogs in my old 93 Ranger back several years ago, and won't direct wire anything like that again), and I'm definitely considering just wiring the relay switch to the parking lights for convenience. However, like you say, then I don't have any control over the fogs, they're always on. While I will probably run them a lot regardless, I would like to have the ability to turn them off.

Thanks for the suggestions.


Nice, thanks. Have you had any problems with the wiring being right there behind your pedals? What did you do to secure the wires against the firewall, to keep them out of the way? Since I've got a manual tranny, I've got 3 pedals to worry about, and there didn't seem to be much to secure the wires to there along the firewall when I was taking a look this evening.

dplummer87

I ran mine down through the center console so they are held out of the way nicely. If i remember right, i think i used a single zip tie to keep them out of the way of the 2 pedals.

nagata

To follow up on this, I ended up wiring my fog lights through the grommet in the driver side of the firewall. I pulled the wire through the cowl to get across the engine bay, then ran it along one of the hard brake lines down to the grommet. Once inside, I kept it tight against the firewall going to the left, then followed wiring up to a new switch I added next to the headlamp selector switch. Worked out very nicely.

I'll probably end up using the same method for a new power line for the seat heaters, though I'd still prefer an in-cab source. We'll see. Thanks again for the input.

jbhill

i ran the power for my stereo in the small grommet right behind the battery. had to snake the wire down past the a/c box, but i got it through. i would run a ignition switched relay to those seat heaters...

nagata

Hmmm, I remember seeing a hole behind the battery, but didn't think it went through into the cab. Does it have wires in it already? I'll have to look for that.

The seat heater kits came with a full wiring harness, but they are just a good switch, wires, and a control box, no relay. I'd prefer relays, but I'd have to wire in 4 separate relays (2 per seat for hi and low heat, 2 seats), and that will create a whole mess of extra wiring that might be difficult to deal with. I'll have to see what I can do, because like you, I feel like that much current should be going through a relay. Maybe I'm just being overly cautious and the switches are just fine for the draw.

Thanks for the suggestions.

1wheel_up

where did u buy ur heaters from?