Jump Start Pack Not Working

[Salomon Thoj]

The situation: Something happens with the 12v supply and once the car is stopped (switched off) dash lights won't come on, central locking won't work, car won't even try to start. No door chimes when key in/door open, etc. Battery OK. Seems to come back after some time. See this video of nothing happening when I turn the key.

Detailed: On Friday I was driving to work and my dashcam shut off, so I pulled over to check it. After checking it was all connected OK (via USB adapter to the 12v socket), I tried to start the engine but nothing happened. Recovery came out and got me started with a jump start pack (although the battery was showing 12v before). On the recovery guy's advice I replaced the battery.

Probably unrelated but: I've currently got a P0410 engine code (secondary air system) showing, which is booked into Subaru for repairs later this month. Hopefully this isn't a red herring for some other electrical system problem.

Also probably unrelated: but I very very regularly get static shocks off the car when leaving it, and when this happens I get a static shock even if I just sat in the car for a minute or two. This could always be the case, since I usually just get in and drive and then experience it upon getting out, but I'll add it here just in case.

The question: What steps can I take next to start diagnosing this? I'm not extremely experienced fixing cars, but I'd like to get a bit more hands on and I do have an electrically knowledgeable friend to help.

You may have a loose or corroded engine ground connection. The next time you have the electrical failure, leave the ignition switch ON and, using a voltmeter, measure voltage between the negative post on the battery and any shiny clean metal part that is bolted to the engine block. This should always read zero volts, or nearly zero. If it reads something like 12 volts, you have a bad engine ground which must be repaired.

EDIT: To diagnose a bad engine ground without a voltmeter, you can use a jumper cable. The next time you have an electrical failure, connect a single jumper cable to the negative battery terminal (first) and a shiny clean metal part that is bolted to the engine block (second). Do not connect the second jumper cable of the pair to anything. If the car starts and everything works, this confirms the bad engine ground. For safety, keep the cable clear of moving parts such as belts, pulleys and fan blades, and do not drive with a jumper cable attached.

There may be a bad connection of one of the main fusible links. Unbolting them and cleaning may fix it. You may need a circuit diagram to identify the exact fault, or you could just clean them all. Make sure you disconnect the battery before doing this.

Welcome to the site, and thanks for putting in a good amount of details. The fact that you have replaced the battery and your seat motors still work when you have the issue eliminates a bad battery or main battery connection. The symptoms sound a lot like a computer issue to me because the computers control the dash lights, ignition, either the computer isn't getting power or it's malfunctioning. The fact it comes back after a time means it could be heat related.

If it's a bad computer that's not really something I'd advise an inexperienced amateur to fix, but you could quickly and cheaply replace the main relay, which could very well be your problem. The position should be somewhere in the passenger side under the dash, but this varies from model to model. Note, that's not the main fan relay, but the main relay. Also check the fuse that supplies the computer to make sure it is seated properly and has a good connection. If that doesn't work you and your friend could use a multimeter to test the connectivity to the ECU (Engine Control Unit).

1) When it's failing look over the circuit with a multimeter. I would connect the leads together through say a 200 ohm, 1 watt resistor--enough to ensure there's more than a trace of power reaching the point. (And this would be even more informative if you see 12v without the resistor but it drops with the resistor.)

I had a similar problem with my car late last year. The car will go totally off and few minutes later turn-on the dashboard again. After few days of struggle and investigation asking battery guys and electricians for help, I discovered that the cables to the battery terminal were loose. The problem totally went away after tightening them.

After replacing the primary cable, I removed the battery post clamp from the old cable, and found myself staring at a handful of wire fragments. The outer layer of cable wires had all broken, causing the primary cable to become intermittent.

Tried to jumpstart my car. It didn't start. Now afterward the car is in worse shape, there are no lights in the dash anymore when I turn the key, regardless of attempt to jumpstart. Hazard lights still work. No other electrical seems to be functioning. What could be going on?

Seems that it did. Cause damage. Guess what the charger does is apply 100A to the battery for a minute or two, then goes back down to "low" until it detects cranking then it applies a bit more power, or some odd.

I tried to use our 2nd vehicle, a 2010 Ford Escape, as the assisting car to jump start mine. But when I looked at the engine compartment of the Escape, I found that the battery is positioned in such a way that the negative terminal is completely inaccessible and there is no physical method that I can find to connect jumper leads to that battery.

But given that the negative terminal is not accessible, I did not want to try it. I eventually borrowed a friends car to jump start mine, but now I'm left wondering, is it possible to use the Ford Escape to jump start another car by hooking the negative lead to another location?

Any ground (earth) location will work. On my '06 Silverado, there are places to hook the jumpers which are away from the battery. You don't even hook the jumpers to the battery no matter which way you're going (whether jumping or being jumped). As long as you have a good ground location, you're golden. Given two vehicles with alternative connection points (places away from the battery), you could possibly have all four locations away from the battery and still be good. This may not be ideal, but it will still work.

As an aside, I was always taught the vehicle doing the jumping should be the last vehicle to be connected, and that the negative on it should be the one which is connected away from the battery. Either way you go, the one which is done last should be the one connected away from the battery. This is because when the last connection is made, the inevitable spark will occur. Batteries release hydrogen gas which can ignite from the spark. By placing the last connection away from the battery, you severely limit the chances of an accidental explosion (think of flames and battery acid going everywhere ... not a pretty thought).

Also make sure the metal you attach the lead to is capable of carrying enough current to start the car. This normally just requires some common sense, for example a small metal bracket attached with one tiny bolt could become very hot and al

Often when vehicles have inaccessible battery terminals there will be specific jump start or charging terminals somewhere more convenient. This is often the case with vans which frequently have the battery located under the passenger seat.

These terminals are often located in the engine bay near the top of the bulkhead on the near (kerb) side usually under a clip on plastic cover. Alternatively there may be secondary terminals near the battery.

How you use a portable jump starter will depend on the model, and you should always read and follow all manufacturer instructions to start a vehicle safely and effectively. The instructions provided here are from the Cobra Jump Starter 800A and 1000A mentioned above, and are typical for most battery-powered jump starters, but always check your product manual before using any device.

Note that if the vehicle does not start after several attempts, your jump starter may stop working (or go into "recovery mode") to prevent the battery from overheating. This may happen if the vehicle battery is too far drained to be able to be jump started.

When used according to the manufacturer's directions, jump starters are perfectly safe and an incredibly useful tool to have on-hand in case of a dead vehicle battery. You won't need to call and wait for roadside assistance to come to you or flag down a passing vehicle to ask for help jump starting your car or truck. In certain situations, your vehicle may even be parked in such a way that makes it difficult or impossible for jumper cables to reach your battery from another vehicle, which makes having your own jump starter invaluable.

Before using any portable jump starter, make sure that it's fully charged, and that all cords and plugs are in good condition. Never use a device that has been damaged or modified, submerged in water, or exposed to rain, snow, or other forms of moisture for an extended period. Portable jump starters should not be used in the presence of flammable fumes or gasses, such as near propane tanks or in the poorly vented bilge of a boat, or near sparks or open flame (including cigarettes).

Bought the Anker Compact Car Jump Starter two years ago, fortunately never had to use it until today. Turning the unit on and plugging the jump connectors to it just cause the green and red lights to blink. Then tried to plug it into the car battery and same green and red lights blinking. Left my car and called an uber to at least get to work.

ive had mine since 2015, still works great. Used it 2 weeks ago to help someone with a dead battery.
Did you try charging it overnight? Have you hooked it to your car battery and put key in accessory mode to see if LED changes?

We are sorry to hear that you are having problems with your Anker jump starter. As suggested by @elmo41683 and @bill_rae, could you please recharge the Anker jump starter to full and then try to jump the car with the following steps?

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