Legacy Wiring Schematics

[Kernie]

Gents:

I have a pre-ISIS car and am in need of any schematics available for the older wiring harness. My electrical works seems to be put together with no rhyme or reason and it's making diagnosis and troubleshooting almost impossible.

My car is overheating because the fans are never turning on. Tracing back the wires to the fuse block/relay is proving to be most challenging. The relays marked FAN don't actually operate the fan and as best I can tell were never wired to operate the fan. What a mess

I'm seriously considering removing all the wiring and starting over with ISIS or simply getting rid of the car.

Anyone have any info on the pin-outs/ layout of the older harness?

Thanks in advance

 

[Will Campbell]

The layouts vary, because each builder needed to modify the harness for their own particular needs. And there are several ways to solve the same problems (e.g., how do I control the steering column tilt/tele?) so no two cars with the old EZ harness are probably exactly the same.

However, diagnosing the current problem (see what I did there???) is a matter of patience and good use of an ohmmeter. I'm guessing that the car worked correctly once, and so the problem is to understand what is broken (intermittent relay connections, for example) or has been bodged since it was originally built.

OTOH, converting to an ISIS system is one way to get something more modern, more flexible, easier to diagnose problems (the LEDs really are useful when you are trying to understand what is wrong), and with all new wiring.

You can also go to the next level with ISIS, with the wifi option if you want to go the technology route as well.

It's a great car, you just need to do the sleuthing needed, or find someone reliable who can, to bring the car back to a happy state.

 

[PeteB]

I used an EZ wiring harness on my Cobra, and it really wasn't designed to be used with an EFI engine. I had to piece together the EZ wire harness and the EFI harness and add wiring for several things. I kept very detailed notes on what I did and labeled everything. Without having notes from the builder it'd be pretty hard to figure out. The manual that comes with EZ wiring harnessess gives a general layout of how to connect things, but doesn't include an actual wiring diagram.

 

[Kernie]

Thanks Will for talking me off the ledge.
As always - yours is a voice of reason.

I have started the diagramming using my trust ohmmeter but uncovering the rats nest has been problematic. There is a lot of splices into the original harness that just doesn't seem to make sense. In some cases wires are run half way and terminated in a ball of tape - strange indeed.

Just going to take more time and effort - was hoping for a miracle.

This is a good life lesson I suppose - I appreciate it that much more when I figure it out.

Thanks for the advice. Much appreciated.

 

[Jack]

I would suggest changing over to the ISIS system if you can. Pull the old stuff out and begin fresh. Takes less a day to install the ISIS, several hours if you know what you're doing. Seems like you would be chasing the EZ-Wire's for a week!

 

[Alex]

It sounds like you've got a real clap-trap of a car there

If you're planning on keeping it i would vote to replace it with an ISIS system - the wiring of one is very straightforward on it, but with your current setup I'd be worried about god knows what other electrical gremlins down the road.

Is the fan problem a new one - I recall you having tuning issues and taking it to a shop where they resolved them .... surely the fans were working then and they weren't dynoing it/etc... without fans running????

 

[Will Campbell]

As you know, H has already installed an ISIS system into his LeMans, and so I imagine he would be comfortable about doing one in your car, should you go that route.

The ISIS system is mostly all positives- less wiring, an SLC-specific wiring harness from the get-go, more reliable switching (because the switches don't carry load current), much better diagnostics, already integrated with security, wireless fobs, ability to go manage motors natively, etc. The only negative is that it has a pretty healthy draw when the car is off. So you need to manage that.

If it were my car, and I was planning to keep it a while, I'd go ISIS in a heartbeat.

 

[PeteB]

There's a smokin' good deal on an ISIS system right now in the classifieds: http://www.gt40s.com/forum/garage-s...arter-kit-plus-remote-control.html#post447243

 

[Kernie]

Just finished updating the wire looms on the superlite. Basically removed (read: stripped) all the wire added by the previous owners and started over. The original wiring loom with fuse block was in good order - just a bunch of stuff added over the past couple of years that wasn't well executed.

Thanks to all for the advise and instructions. Working fine now.