I have a 2003 Grand Marquis Ultra and can't find any places to run 12 volts from the battery through the firewall. The engine compartment is full and from what I can see under the dash I can't find where wiring comes through.
My plan is to remote mount my Yaesu and Icom ham radios plus my Spectra UHF radio in the trunk.
How can I get power from the battery to the trunk for three radios and some strobe lights? I'm not at all mechanical and have never done an install in a car.
Thanks for any help offered!
George
Help running 12v to trunk in 2003 Grand Marquis
Moderator: Queue Moderator
Not vehicle specific, but i can offer some suggestions.
Find the interior fuse panel and follow the main harness from it, it goes through the firewall somewhere under there.
Follow the hood release cable, the parking break cable, the throttle cable, they all go through the firewall somewhere and a lot of the time they use a nice big rubber grommet that leave room for other stuff.
With all of the vehicle installs i have done i have yet to drill a hole in a firewall to add a grommet.
Find the interior fuse panel and follow the main harness from it, it goes through the firewall somewhere under there.
Follow the hood release cable, the parking break cable, the throttle cable, they all go through the firewall somewhere and a lot of the time they use a nice big rubber grommet that leave room for other stuff.
With all of the vehicle installs i have done i have yet to drill a hole in a firewall to add a grommet.
Duct tape is like the force, it has a dark side and a light side and it holds the universe together.
"I Reject Your Reality And Substitute My Own!" - Adam Savage
"I Reject Your Reality And Substitute My Own!" - Adam Savage
Go to the passenger side front foot well. Check about midway between the tunnel and the kick panel at the point where the floor board angle meets the vertical section of the firewall (about where the upper edge of the carpet ends). Pull the carpet and the insulation back a bit if necessary. There is a harness pass-through there that has a large-bore center suspension grommet. That means there is plenty of room to poke a hole through the suspension portion of the grommet next to the harness itself.
I use a Phillips screw driver to make the initial "poke" and then enlarge it with a larger Phillips if necessary. I usually pass a large wire properly fused at the battery connection post on the relay module through the grommet hole to the car interior and attach that end to a fuse block and distribute power to all the "toys" from there.
You'll have to fish the wire beneath the heater fan motor assembly (on the engine side of the firewall) and up to the right side of the wheel well next to the inner fender panel, where you can then route it to the relay box's battery connection (10 mm hex nut). A base loaded antenna whip and a little tape makes an excellent tool for doing so.
I'm hoping that the Crown Vic/Grand Marquis civvie models have this pass through since I've only had my paws on the public safety/police interceptor models. If not, I apologize in advance.
Hope this helps.
I use a Phillips screw driver to make the initial "poke" and then enlarge it with a larger Phillips if necessary. I usually pass a large wire properly fused at the battery connection post on the relay module through the grommet hole to the car interior and attach that end to a fuse block and distribute power to all the "toys" from there.
You'll have to fish the wire beneath the heater fan motor assembly (on the engine side of the firewall) and up to the right side of the wheel well next to the inner fender panel, where you can then route it to the relay box's battery connection (10 mm hex nut). A base loaded antenna whip and a little tape makes an excellent tool for doing so.
I'm hoping that the Crown Vic/Grand Marquis civvie models have this pass through since I've only had my paws on the public safety/police interceptor models. If not, I apologize in advance.
Hope this helps.
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