running wires through firewall

Could someone help me? I have a 2006 Toyota Sienna and I am trying to run wires for some accessories from the engine bay through the firewall and into the cabin. I can see the location and point of entry that my Clifford alarm system's wires enter through the firewall, but I can't easily access it. Is there a method that I can use to make this process easier? The engine bay is really tight and I don't have much options. I wish I was there to see them install the alarm, then I would have a better idea of how they ran the wires through the tight spaces. Please help!

Can you access it from inside the car? If so, I would send out a "pilot" wire to the engine bay and try and grab it and then you can tape your wires to it and pull your wires (if not to large for the whole/gromit used) into the cabin. If not, I would say you are better of trying to figure out access in side the cabin rather than the engine bay. You may need to remove some stuff to gain access. Hope that helps.

Did they run it through a wire grommet or does it look like they drilled a hole? If it is a grommet i use a 3 ft. fiberglass pole and shove it through, tape the connections i need to run to the pole, and pull it through. Otherwise, just drill a new hole, or find a different grommet.

Thanks guys! Actually, they ran the wires through an existing rubber grommet. The space is so tight though, and from inside the engine bay I can't fit my hand to reach the grommet (I can barely see it too). I'm thinking that I may need to remove the airbox to gain better access and try to wiggle my fingers around the plumbing. I'll probably need to remove the dash too. I just didn't want to go through all the extra steps if there was another "easier" way. The alarm installers were able to get in somehow to run their wires...we'll see.

If you have space problems, two similar alternatives to Yimke's idea, can you get white net curtain rod in the US, plastic covered wire about 1/4" dia, or bicycle brake cable, OR I took a cabinet screwdriver, filed the sharp end, use that to poke through the grommet. Acombination of 1 or all of the above has never failed for me.