Running wires through firewall

[D68enny]

I am trying to run some wiring through the firewall and have read on the site that the easiest place to run them through is the hole for the antennae wire. My question is where does that wire run through on the firewall side of the engine bay? Does it come out right under that big black plastic case around the AC evaporator or whatever that AC thing is right by the firewall? Do I have to remove one side of that box to get to the hole? I pushed a wire through from the inside to grab the wires in want to run, but can't find the wire I pushed through. I wanted to ask for some help before I start taking things apart to hunt down that wire.

Is there a place on the driver side to get through? I see where the maine wire harness goes into the cab, but cannot see it from the inside of the cab. Is it way up at the top of the dash area? That would be a better place for me to get the wiress through. Thanks.

[HenryJ]

For the passengerside firewall grommet-



The wires enter the engine compartment below the HVAC. You can access it through the right side inner fender easily if you have a body lift. If not you may have to climb on top and reach down under to grasp the wire.

For the otherside you can go through the rubber boot on the bundle that comes through the drivers side firewall , between the fender and brake booster.



To do this remove the lower dash panel that includes the OBDII port, above the drivers footwell. You will need a long piece of rod. I use gas welding rod, or fluxless brazing rod. A straightened metal coat hanger may work well too.
Poke it through the rubber boot from the engine compartment piercing through to the inner seal and into the footwell. If the rod is thin like the welding rod I bend the end back in itself and insert the stripped end of a wire through the tightened loop. The tape it tightly and pull it back through to the engine compartment. The next time will be easy as the rod will follow the wire back through.

[D68enny]

Thanks HenryJ. I have that part done. I have another question about the wiring. I am installing two 150 watt KC lights and the kit comes with factory wiring. The problem I just encountered is that after running the wires over to the passenger side and then back over to the drivers side on the inside of the truck I am about 2.5 feet short on the power supply that goes to the switch inside the truck. Can I add the wire needed to reach the power source without cutting into the light performance?

The switch is a 3 prong on/off switch with a ground, power supply and load.

One last thing. Is there a ground source inside the truck that is easy to get to? I have about 3 feet of supplied ground wire and need to find a place to hook it.

[HenryJ]

As long as the size of the wire is still capable of supplying the needed amperage you should be fine to extend it. Solder and heat shrink would be the preferred method of adding an extension. The base of the steering column has a bolt that could be used as a ground. Also look around the emergency brake for good bolts to ground to.

There should be no reason to go to the passenger side and back. Sometimes "factory" wiring is not the best choice. I like to use the relay ground for activation. If you have a lighted switch you may have to use the positive instead. Lots of ways to wire a light. Make sure you are using a relay and fuse the power wire close to the source. Make your runs as short as possible and when in doubt use heavier wire.

[green02crew]

Question on this, I wanted to cut down on length of wire to run to the battery, running through the passenger side would work for me but it does go pretty close to the engine. Would the heat be too much for wire?

[F9K9]

It hasn't been an issue for me when going through the antenna's grommet on the passenger side.

[HCO4x4]

yea, i've run power wires through there in my old blazer and the crew. no worries

[green02crew]

Good to know, thank you!