Ultima Wiring Harness Observations and Upgrades

[bigmack]

Greetings Chaps,
Recently I had a look at my ignition switch on my 1998 Sports, b/c Jeff Schwartz complained that his ignition switch failed while on the Hot Rod Power Tour. I'd also read a PH post from another fellow who had an electrics guy look his harness over and made a few modifications. I spoke to Ted@Ultima about this and he has advised me that ultima now supply an updated harness with larger main power wires and an upgraded ignition switch. I decided to research this a little and make a few modifications to my harness to "bring it up with the times". I cannot make any guarantees concerning these mods, and you should always consult an electrical expert if you are unsure of what your doing. Upon inspecting the ignition switch, I found the two brown wires had melted and fused to the ign. swtch. pins. One of these runs from the battery to the switch and the other runs from the ign. switch to supply the light switch. As an American, I noticed that there is a different standard for American and UK wire. Here is a link to a site that converts between the two www.simetric.co.uk/siwire_elect.htm
I spoke to a few experts who advised me that the brown wire(which runs from the battery to the ignition switch) should be a minimum of 10AWG (gauge) wire in diameter. The Ultima wire appeared to be about a 16AWG. Next, I decided to beef up the two white wires running from the Ign.Switch to the fuse panel. These two white wires turn into two green wires after the fuses. Each green wire is soldered to about 6 green wires that supply various components(one of which is the volt gauge). I ran two new larger diam. green wires and soldered them in place of the two existing 18 AWG ( 1mm) green wires. This cured my problem of voltage differences I was getting when all accessories were running (measured at the battery vs. measured at the dash volt gauge). The last thing I decided to do was upgrade the wires running from the alternator and starter to the battery. The American aftermarket wiring harness manufacturers are using a minimum of a 1/0 (pronounced single ought) starter wire for hot rods that have trunk mounted batteries with front engines. Some are using 2/0 wire. If you do this, then be sure to run an equal diam. 1/0(or 2/0) ground wire, preferably, from the starter bolt to the chassis. Welding supply houses can provide you with the wire, but you'll need to search around for appropriate connectors. I kept my existing ground strap and added the 1/0 starter ground wire from the starter bolt to the chassis. Lastly, I'm told that the wire running from the alternator to the battery needs to be a minimum of 8AWG(preferably a 6AWG). I upgraded this as well(after all I had to do something with the old starter wire . All of these mods have ironed out my electrical glitches and I have cool wires now. These mods took about 2-3 comfortably paced nights to perform and I was able to do this all with the existing wiring harness installed in the car. I'm not sure when the Ultima harness was revised, but if you are running a few added accessories, then you might want to inspect your ignition switch and go from there. I'm sure the factory can supply you with appropriate recommendations.
Cheers!
-Mack

[bigmack]

p.s.I also took the factory ignition switch, found the closest body of water, and threw it as far as the eye could see
Replaced it with an all brass higher amp ignition switch.

[bigmack]

p.p.s I almost forgot to give my buddy Jack Rosen kudos for supplying me with an excellent wiring schematic of the Ultima harness. It was invaluable in my quest to beef up the harness. For me, it is so much easier to follow the wiring on a schematic diagram than to try and decipher the factory wiring list.
Cheers!
-Mack