Honda City Cluster Repair
Honda City 2017 Dashboard | Cluster Repair: A customer came to our shop with abnormal instrument cluster behaviour and wrong data on guages. We did all kind of tests to find out the problem but couldn’t fix, at the end we just found a bad ground point on Meter circuit board. Fixing that ground fixed our problem. No IC replaced, no cluster replaced, no expensive repair. Just repaired and solved the problem.
How does grounding complete the circuit?
There are some great answers on why grounding doesn’t complete the circuit but I feel it doesn’t address the differences between grounding and grounded.
Grounding means where there’s a direct, unimpeded path to ground and is used as a safety device to cause such a spike in power that it causes the fuse or breaker to trip. Grounded is a return path that may or may not be somewhat impeded where the wire goes back to a panel that is itself grounded, meaning it connected to a grounding point so that you have a frame of reference for the higher voltage on the line side.
So based on the assumption you want to know why something eventually has to go to ground to complete a circuit, I’m going to use an analogy.
Ok, take the Earth. This biiiiig ball, and I want you to imagine it shrinking down into this itty bitty tiny little point… that point is now your ‘ground’ reference for the system. That is essentially the common point no matter where you go, that earth point, or ground is the point that is always zero volts. We typically show it like this:
Now, since that point is zero, imagine you have a ball in your hand. If you let that ball go, it still wants to drop to the ground. No matter where you hold that ball, it wants to drop from where it starts down to the ground. In physics, we describe holding the ball in the air as “potential”, and just like physics, it’s the same thing. That ball has potential to fall to ground, but your hand is in the way. If you let go, that ball falls to the ground and that’s it. In electrical terms, potential can also mean voltage. So that ball is not just any ball, it’s a tiny electron, and it wants to go to ground.
Now imagine instead of a single ball, we had a box full of them, and a spout you can turn and adjust the flow rate, like water, of the balls falling out of the box. The spout in this case acts as a resistor, impeding the flow of electrons. That flow is the amperage, and the more you open that spout, the less resistance, and so more flow.
If you reach down and cup your hand to catch some of those electrons as they fall to ground, your hand acts like a capacitor, and you releasing your hand is like a capacitor discharging. You can also imagine an inductor as a tube with a coil or two in it. The coil fills with electrons that have nothing to stop them at first, but the loop causes them to slow down. As more electrons fill the loop, it pushes them along. It slows the flow, but doesn’t stop it.
That’s the way I describe it to people who don’t quite get how electricity works. It’s the best analogy I have, and doesn’t cover some of the weirder concepts like alternating current (where some of the electrons turn around and go home) but it’s enough that you can get the gist of what’s happening in the system.