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A REAL Schematic

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BSWOR you should consider pinning this post. 

A REAL Schematic

Until now there were no entire car schematics for our cars, only wire diagrams. This schematic is 5 pages in four separate pdf files (a quirk of my CAD software).

A real schematic rarely makes any attempt to identify wires or plugs or connectors. A real schematic tries to show the internal workings of a component when it helps to explain a circuit. A real schematic simplifies. A real schematic is used when you want to understand how a circuit works.

A real schematic is what the designer makes first, then he converts it to a wire diagram. A wire diagram shows where wires go and how to connect them. You need BOTH to work on a car, unless the wire diagram is just so darn simple you don’t need the schematic.

Our electrical systems consist mostly of switches and lights; around 44 and 41 respectively. Switches are either open or closed. This schematic only shows when a switch is closed. Usually that is indicated by a few simple words below the switch like on, off, run, start, etc. Pay attention to the top section of page one. It shows the most often used symbols on the schematic.

I started this project so I could calculate the electrical loads and know what size alternator to get for my future needs (EFI, fuel pump, halogen lights, power windows, etc.) Amperage information for a stock 1969 Mach1 is in an accompanying spreadsheet (Mustang amps.xls) along with a chart of our most common electrical load: light bulbs. If you don’t like the loads I used to calculate “Likely constant amp draw”, by all means alter the spreadsheet to suit your needs, or use simple math- just don’t complain to me.

My hope is that this schematic and spreadsheet become valuable reference tools for other hobbyists. Edit: I've seen quite a few questions about the 1970 turn signal circuit so I started another topic for "1970 Mustang Exterior lights".

 

MUSTANG SCHEMATIC PG1.pdf

MUSTANG SCHEMATIC PG2.pdf

MUSTANG SCHEMATIC PG3.pdf

 

 

Mustang amps.xls

MUSTANG SCHEMATIC PG4.pdf

 

 

 

 

MUSTANG SCHEMATIC PAGE 5.pdf

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I was studying the scheematic today as I could not for the life of me work out how a Mustang is wired for the brake lights to flash as blinkers. Not legal in Australia.

The diagram was extremly helpful and I will now have no problem splitting them.

Thanks again

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Yes the turn signal switch and 1157 bulbs make for a tricky little circuit. Its something you can never figure out from a wire diagram. The Schematic simplifies that. Glad to help.

BTW, things get real interesting when you loose the ground to one of those 1157 bulbs- then it searches for ground by passing through other bulbs and lighting them up. You should be able to follow the path and see what is happening on the Schematic. 

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10 minutes ago, Mach1 Driver said:

Hey another Georgian, welcome to the insanity. What'cha driving?

Thanks. I have a few '69 and '70s. '70 T5 Grande, '69 Grande, '69 coupe, '69 fastback, '70 convertible, and '70 XR7 Cougar. Only the T5 is in good running and presentable condition at the moment, I have not driven the others for a long time and now they are project cars. Currently working on the '69 Grande, fixing a few dents and a few rusted spots. Hoping to get that on the road this year.

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1 minute ago, aslanefe said:

Thanks. I have a few '69 and '70s. '70 T5 Grande, '69 Grande, '69 coupe, '69 fastback, '70 convertible, and '70 XR7 Cougar. Only the T5 is in good running and presentable condition at the moment, I have not driven the others for a long time and now they are project cars. Currently working on the '69 Grande, fixing a few dents and a few rusted spots. Hoping to get that on the road this year.

Wow a whole stable of ponies! Ah, but nothing is real without pictures- let us see your babies. 

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5 hours ago, Grabber70Mach said:

@Mach1 Driver Thanks for aall the hard work doing this.  I'm getting a 2C171/1

error when trying to download the 4th one.

You are welcome, and yes it took some work.

It downloads for me- anyone else have trouble downloading page 4?

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Thanks. It took a bit of work, but I just couldn't stand looking at those silly wire diagrams and still not "see" how it works. Now I can just glance at the schematic and think "oh yeah, this is how it works". Back in the day I would only look at a wire diagram if I had to calculate amps for wire gauges or spec terminals or connectors. I would always use a schematic to diagnose a problem.

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