This has been bugging me for awhile and hope someone can explain.
For starters, look at this wire schematic I made of my '86 Capri 5.0
This is an accurate diagram of what I've found in all three of my '86 Capris and my '82 has basically the same set up... and I'd bet all '79-'93 Foxes are the same way.
What I'm questioning is why did Ford do it this way? The small green wire coming from the starter relay "hot" post is the only wire that is feeding the ENTIRE car. It's also the only wire through which the alternator can charge the battery.
Take a look at this pic... it shows the green wire I'm talking about. It's a 14gauge wire and comes off the starter relay, down to the shunt, then branches off to run ALL the electrical components of the car (except for the EEC/fuel pump relays and under hood light).
Common sense tells me that if I'd have all the lights on, wipers going, radio blasting, heater blower on high and rear defrost on, it would be drawing way more power through that wire than it's rated for. This seems like a fire hazard to me, but yet I've never heard of any Foxes burning down because of it.
I understand the alternator is supplying power to the area below the shunt so not ALL the power is being sucked through that green wire, but what happens if the alt fails? Then ALL the juice MUST come from the starter relay via that green wire.... and even when the alt is operating properly, it has to try to force it's charge through that stupid green wire to charge the battery.
So, is this just a poor design by Ford that has managed to exist without causing any problems or did they do it this way for a reason? Like that stupid shunt for instance. I'm confused at WHAT it is exactly.... I took one of my Capris wiring apart to "fix" this problem and attached all the different wires to a power block instead of being fed by that single puny green wire and removed what I believe is the shunt. It was nothing more than all the wire ends encased in a molded chunk of solder.
I cut it out along with all the fusible links and then attached all the wires to a fused power distribution block, including the wires from the alternator... which is another thing that doesn't add up. The two black wires that come off the alt only go a short distance then bottle neck down to only ONE wire. I have been aware of this problem and that it is addressed when switching over to a 3G alt. But, they eventually connect to the same spot the yellow wire from the alt connects to... why not just run one large wire from the shunt area to the alt?
Same deal with the Amp Gauge, it has two wires and both connect to the same power source (that infamous green wire) except they connect at different points on that wire.... why is that? Does the shunt have to be there for it to work... I don't think so, because I just twisted both ends of the amp gauge wires together and then ran it to the power dist block and the gauge works just fine.
All of these things have had me scratching my head and wondered if anyone else has noticed this?
For starters, look at this wire schematic I made of my '86 Capri 5.0
This is an accurate diagram of what I've found in all three of my '86 Capris and my '82 has basically the same set up... and I'd bet all '79-'93 Foxes are the same way.
What I'm questioning is why did Ford do it this way? The small green wire coming from the starter relay "hot" post is the only wire that is feeding the ENTIRE car. It's also the only wire through which the alternator can charge the battery.
Take a look at this pic... it shows the green wire I'm talking about. It's a 14gauge wire and comes off the starter relay, down to the shunt, then branches off to run ALL the electrical components of the car (except for the EEC/fuel pump relays and under hood light).
Common sense tells me that if I'd have all the lights on, wipers going, radio blasting, heater blower on high and rear defrost on, it would be drawing way more power through that wire than it's rated for. This seems like a fire hazard to me, but yet I've never heard of any Foxes burning down because of it.
I understand the alternator is supplying power to the area below the shunt so not ALL the power is being sucked through that green wire, but what happens if the alt fails? Then ALL the juice MUST come from the starter relay via that green wire.... and even when the alt is operating properly, it has to try to force it's charge through that stupid green wire to charge the battery.
So, is this just a poor design by Ford that has managed to exist without causing any problems or did they do it this way for a reason? Like that stupid shunt for instance. I'm confused at WHAT it is exactly.... I took one of my Capris wiring apart to "fix" this problem and attached all the different wires to a power block instead of being fed by that single puny green wire and removed what I believe is the shunt. It was nothing more than all the wire ends encased in a molded chunk of solder.
I cut it out along with all the fusible links and then attached all the wires to a fused power distribution block, including the wires from the alternator... which is another thing that doesn't add up. The two black wires that come off the alt only go a short distance then bottle neck down to only ONE wire. I have been aware of this problem and that it is addressed when switching over to a 3G alt. But, they eventually connect to the same spot the yellow wire from the alt connects to... why not just run one large wire from the shunt area to the alt?
Same deal with the Amp Gauge, it has two wires and both connect to the same power source (that infamous green wire) except they connect at different points on that wire.... why is that? Does the shunt have to be there for it to work... I don't think so, because I just twisted both ends of the amp gauge wires together and then ran it to the power dist block and the gauge works just fine.
All of these things have had me scratching my head and wondered if anyone else has noticed this?
