Ultima Wiring Harness Observations and Upgrades
Discussion
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
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
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
Cheers!
-Mack
I'm just about to close all of the wiring in by fitting the roof, and remembered that there was talk of wire problems on old threads.
This thread (Nov 2003) seems to outline the problem, and says that the factory has upgraded the harness to overcome this problem.
There are two other threads that talk about this issue below:
www.pistonheads.com/gassing/topic.asp?t=108573&f=20&h=0 (June 2004)
www.pistonheads.com/gassing/topic.asp?t=110417&f=20&h=0&hw=ignition+wires (July 2004)
In both of those threads the people with the problems seem to have an earlier loom (1998 and 2001).
Has anyone with a newer loom (i.e. post 2003) had any problems that others should be aware of?
This thread (Nov 2003) seems to outline the problem, and says that the factory has upgraded the harness to overcome this problem.
There are two other threads that talk about this issue below:
www.pistonheads.com/gassing/topic.asp?t=108573&f=20&h=0 (June 2004)
www.pistonheads.com/gassing/topic.asp?t=110417&f=20&h=0&hw=ignition+wires (July 2004)
In both of those threads the people with the problems seem to have an earlier loom (1998 and 2001).
Has anyone with a newer loom (i.e. post 2003) had any problems that others should be aware of?
Due to the Large amount of modifying I was going to do while building Waynes GTR, I had a proper Wiring drawing made of the original. It's a Microsoft Viseo programme, but I'll see If I can make a Jpeg from it I will post the full drawing. I have been though it completly, and it is correct.....
>> Edited by gtrclive on Tuesday 18th April 18:29
>> Edited by gtrclive on Tuesday 18th April 18:29
Ultima Factory said:
To our knowledge no customer has reported any inherent faults with the standard Ultima wiring loom apart from a concern over the ignition switch which was upgraded some time ago.
I called the factory a couple of times back in 2002 and mentioned that my voltmeter dropped from 13.5V to 11.5V when the blower, AC and wipers were on. I suggested this might be a wiring loom problem, and I think you thought it might be an alternator problem. This problem was solved by the addition of a relay providing power to fuse one and reducing the current through the ignition switch, as detailed in my post:
[url]www.pistonheads.com/gassing/topic.asp?t=110417&f=20&h=0&hw=ignition+wires[/url]
You might clasify this as an ignition switch problem, but my thoughts are that having all the accessory load passing through the key switch isn't ideal.
YIIHAA said:
To our knowledge no customer has reported any inherent faults with the standard Ultima wiring loom apart from a concern over the ignition switch which was upgraded some time ago.
I called the factory a couple of times back in 2002 and mentioned that my voltmeter dropped from 13.5V to 11.5V when the blower, AC and wipers were on. I suggested this might be a wiring loom problem, and I think you thought it might be an alternator problem. This problem was solved by the addition of a relay providing power to fuse one and reducing the current through the ignition switch, as detailed in my post:
[url]www.pistonheads.com/gassing/topic.asp?t=110417&f=20&h=0&hw=ignition+wires[/url]
You might clasify this as an ignition switch problem, but my thoughts are that having all the accessory load passing through the key switch isn't ideal.
I don't know anything about the Ultima beyond how it looks. I did have a quick squint at that drawing though. I'm an electronics engineer, so it was kinda natural.
It did strike me that there seemed to be quite a number of loads switched directly through the ignition switch. Depending on the ratings, that may be O.K., although I suspect not because people are talking about increasing the wire guage.
I'd certainly include a few more relays if it were mine. The most objectionable loads look like the Heater Motor and the wiper motor. Even if the loads are numerically within the spec of the ignition switch, it's much better to use a relay for inductive loads that are likely to be running when you turn the ignition key.
The inductive loads (motors) will produce a significant spike when they are switched off. If that's the ignition switch you'll get a small spark across the switch contacts. Eventually this will kill the contacts. It's easier to replace a relay than a keyswitch.
Well, you asked for suggestions!
HTH.
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