Tapping the Firewall

jordanf1 · Jan 31st, 2006, 06:59 PM

Hi!
Im planning to do the cluster swap on my 88 2 door sedan. Its looks like a simple process and Im quite good at doing this sort of thing. Where exactlly must the firewall be tapped to run thje tach wire? I read in one of the posts that it must be done near the left side. WHERE EXACTLLY??? Im thinking that is near the driver's side (left side when sittin in the car)? Ive never tapped a firewall before and i want to get it right the first time!
Thanks a lot! this site is great.

sentrastud · Jan 31st, 2006, 10:05 PM

Hahaha, tapping the firewall sounded like an intense process to me, so I took the easy way out.

Just run the necessary wiring through the body panels and in through a door. I used this technique for my interior Neons. Go to my website and download the microsoft word version of the lighting write up. In it theres a few pics of how i got the wire in.

Alternatively you could run the tach of the ECU tach feed wire (its red and white and on the ECU harness, see the sticky about the swap for complete info).

The easiest way though is probably to get the tach feed off the OBD port. Although I havent heard of anyone on this site doing it, my friend used it in his 1982 Chevy to wire his tach. If im not mistaken its a red and wire that leads into the back of the OBD port (the port should be located next to your fuses). This wire is in a really convient location near the dash and should make your swap really easy if you can find it.

-Nick

dreamteam · Feb 1st, 2006, 12:16 AM

If tapping the firewall means drilling a hole,
it's not that hard.
On mine i looked for an uncluttered spot
which turned out to be right below the master cylinder.

Before I drilled , I checked inside to make sure I wasn't going to drill into anything else.

Wire is in now and out of the way.

PS Your car is not new enough for an obd port. ( I think)

astreamk1 · Feb 1st, 2006, 06:45 AM

I ran my tach wire out through the grommet around the throttle cable. poked a hole through it with an awl. easy to get to under the hood, close to your coil. very accessible under the dash. not really necessary to drill a hole for that one small wire.