The Exocet doesn’t really have any kind of dash board. No place to install the harness, fuse box, relays, etc. So I had to make one. You can now buy one from Exocet. But I’m cheap. And, although not particularly talented, I am handy. So I made one. Worked out pretty well, IMO. Deeper than the one from Exocet, and also useful as a dash board.
In installed an 8 circuit harness from Summit Racing. I purchased a Painless Wiring, because I’m familiar with them. But there are a umber of good products available. Pick the one you like best. BUT…. don’t cheap out here. A good harness is easy to work with, and will do what you want it to. A cheap harness will be a real PITA.
Never buy cheap parts, they’re too expensive.
I chose an 8 circuit harness. Just the basics. This is a track car. But I do want to be able to get a license plate and insurance. You can do a lot of tuning and test driving on the highway. So it needs turn signals, headlights, etc.
Wiring from the front to the back goes through the transmission tunnel. I copied (shamelessly) from FM, and welded in a bar to connect the firewall to the trans tunnel. Before I welded it in, I drilled a bunch of #30 (1/8″) holes, so I could attach the adel clamps with rivits. In case you didn’t notice, I use rivits for a lot of stuff.
A couple of big hints here:
- Document your wiring harness carefully. Eventually, you’ll want to change something.
- Neatness counts.
- Put connectors where it will make your life easier. Think of pulling a few plugs and dropping the engine. Buy a kit from someplace like DIY Auto Tune. I like Weatherpack plugs. But Deautsch plugs are pretty nice, too. There are some new ones that might even be better.
- Protect the wires. Use whatever loom cover you like best.
LS1 Alternator
2/6/16: A special note about the LS1 alternator.
The F-body LS1 uses a single wire alternator. This single wire is connected to the ECU, which controls the charging rate. The charging rate is controlled by a program that varies the charge depending on things like temperature, engine load, throttle position, etc. Mostly an attempt to gain more fuel mileage.
If you install the LS1 along with the stock ECU and wiring harness, just plug everything in and don’t sweat it. If you’re using an aftermarket ECU or a carb, then you’ll need to use a 2 wire plug, a resistor, and a diagram similar to this.
Painless Wiring sells this plug and resistor kit, that is available from a variety of sources. I got mine from Summit Racing. You might be able to save a couple of bux sourcing these parts individually.
There are a couple of different ways to accomplish this goal, but this is the one I found easiest to do. I connected this up, and immediately got 14.10v.
Unfortunately, I did not find this information in the instruction book for the Painless Wiring harness.
In previous reading, I found many people who stated to simply place a 470K ohm 1/2 watt resistor in the line, and it would work. But, that didn’t work for me; I don’t know why.
I am using a Megasquirt MS3+ ECU. I could connect that one wire into the ECU, and it would control it in the same way the stock ECU does. But I was concerned that if the alternator started to fail and got noisy, it could take out the ECU. Maybe that can’t happen, and I was worried about nothing. But keeping them separate like that helps me sleep at night.