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Old 07-19-2014, 10:38 AM
4,762 posts, read 10,243,358 times
Reputation: 7798


Originally Posted by thompsongirl1997 View Post
So how do you fix a ground problem?!
I once found a loose ground connection from the engine to the body/battery negative by doing a voltage drop test. The loose ground connection was where the ground wire connected to the engine.

I fixed it by removing the bolt and the wire/ring terminal. Cleaned the mating area, ring terminal, and bolt with brake parts cleaner. Then reattached the bolt/ring terminal/wire. And tightened the bolt with a torque wrench to what was specified in the vehicle manufacturer's factory service manual - for that specific bolt.

Voltage Drop Test...

Diagnosing Voltage Drops - Electrical Automotive Troubleshooting

FYI - A loose ground connection to the engine will keep the alternator from charging the battery properly and keep most engine electrical gizmos (like spark plugs) from working properly. Spark plugs have one wire - the "other wire" is the ground! (Quite important!)
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Old 11-02-2014, 05:49 AM
1 posts, read 3,142 times
Reputation: 10
I hope somebody could help me on how to hardwire a device to the car fusebox. Here is a view of my car fusebox:


As you can see, there is an existing red/black wires (red wire connected to fuse slot 23, and black wire I believe was grounded). These I think are the wires to the in-car camera a mechanic installed for me some months ago to power up the camera...

I just bought an OBDII scan gauge. It has an option to power up using the cigarette lighter outlet or through hard-wiring. To minimize clutter, I've chosen to hardwire it to the fusebox and decided to do it myself... Should I connect the positive (red wire) to an empty fuse slot such as the slot I labelled 1 on the picture, and to ground the negative (black wire) to the hole labeled 2? Is it possible to also ground the negative wire to labelled 3, together with the existing in-car camera ground wire?

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Old 11-02-2014, 07:08 AM
Location: Columbia SC
7,969 posts, read 6,725,053 times
Reputation: 10715
Look at it like this. In an electrical device it must have a hot/voltage/electricity/positive wire and a negative/return/ground wire. The positive must come from the battery so there will be a wire from the battery to the device. That wire might run all over hell but it will come from the battery. The chassis of the car being metal can serve as the negative/ground wire so no need the run a wire back to the negative side of the battery. Just get the negative wire of the device to ground/chassis thus saving wire. If the device loses its ground or becomes intermittent it will not run or malfunction while the rest of the cars electrical devices run fine.

The battery negative is wired/attached to ground/chassis and if this connection acted up, the entire electrical system would have problems.

Keep in mind a cars system is DC (Direct Current) as are all batteries. Your home is AC (Alternating Current) thus wired different.
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Old 11-02-2014, 07:27 AM
671 posts, read 618,585 times
Reputation: 1243
Everything uses power..The battery delivers electricity by two leads a positive and a negative lead.
For any electric device to work it needs power from a closed circuit..That is to say the negative lead and the positive lead must reach from the battery to the device...The negative lead is referred to as the ground lead and is common to all devices....
The negative side of all devices can touch each other while the positive side is actually the one that is switched on and off to close the circuit and allow the device to operate....
The odd part is that the power flows from battery from negative to the positive side...That is the most commonly misunderstood function of a DC power supply.
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Old 02-02-2015, 01:49 PM
1 posts, read 2,946 times
Reputation: 10
So I got a 1997 Mitsubishi mirage and I be leave I have a grounding issue Cuz my lights dim and undim at higher rpms and was wondering if anyone coulded help me find the problem
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Old 04-11-2015, 06:25 PM
2 posts, read 36,486 times
Reputation: 11
probably too late . 2001 Grand cherokee. starts ,drives but then quits,and won`t start,after a bit,it starts till it quits again, then it goes again ,and on and on. Code 0320 comes up. crank sensor? disconnect battery and reconnect and it would not start. and code was p-0320 again. then still no start so we left it sit.came back reconnect battery and No codes. runs ok,but noticed loose ground strap from engine to firewall.so it tightened up. now no quit issues so far but just idling. It quit before just idling. Now no codes come up and it won`t quit.like before? all because ground to engine or?
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Old 07-19-2015, 02:55 PM
5 posts, read 10,388 times
Reputation: 10
I have a 98 Lincoln Town car when I tried to start my car the motor ground strap burnt up I replaced it burnt again. bought 2 more and cleaned terminates, and checked relays. I just replaced battery starter and alternator.
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Old 07-19-2015, 02:56 PM
5 posts, read 10,388 times
Reputation: 10
But it still want crank and ground straps are still getting hot.
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Old 07-19-2015, 03:55 PM
Location: Not far from Fairbanks, AK
16,174 posts, read 27,449,163 times
Reputation: 11838
To make it very simple for the OP I will explain it this way:

a. In your car the negative (-) post of the battery is the ground side. In this case this ground side is connected to the vehicle's chassis somewhere along the line. On the same battery the positive (+) is the opposite of the ground side.

b. Every electrical component in your vehicle has a positive and a negative side. For example, a socket with a lightbulb in your car has a positive and a negative lead or wire. If you remove the socket and lightbulb from the car, and then connect only the positive lead the battery's positive post (also called pole), the voltage from the battery makes it across the bulb, all the way to the end of the negative lead. In this case the negative lead is in an "open" ground condition, and the bulb does not illuminate. But connect the negative lead to the ground (chassis, or any metallic component that is grounded), and the bulb illuminates because the "open ground condition" is removed.

c. Every electrical component in you car depends on a "close" circuit in order to work. If you now cut the socket's positive lead, but not the ground lead (leave this one connected to the chassis), you are opening the power side of the circuit, and the lightbulb won't illuminate. But lets imagine that in the "cut" you install a switch to connect both sides of the power lead, in this case you can turn the light off and on by just opening and closing the switch.

d. Some of the electrical components in your car are grounded right at the casing, while others are grounded at different locations throughout your car.

e. Sometimes the open condition happens on the positive side as well as on the negative side. It also can happen right within the component itself, so don't believe for a minute that everything is about an open or loose ground.

f. A loose ground as well as a loose + wire can cause the component to work intermittently, but in general a loose ground creates a hot spot on the ground lead, often right at the spot where it is grounded.
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Old 07-19-2015, 03:58 PM
5 posts, read 10,388 times
Reputation: 10
I have a 98 Lincoln Town car when I tried to start my car the motor ground strap burnt up I replaced it burnt again. bought 2 more and cleaned terminates, and checked relays. I just replaced battery starter and alternator.
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