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Questions tagged [electrical]

Concerning the main electrical system of a motor vehicle or internal combustion engine. Consider using [tag:electronics] for radios and other such systems. Use [tag:electric-vehicle] for questions about electrical powered vehicles and their unique systems.

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41
votes
3answers
20k views

Jump starting a dead battery: Connect black wire to negative pole of battery or grounded metal?

Most of the advice I've seen for jump starting cars instructs to connect the black wire to a bare piece of metal on the car with the dead battery. However, I've always just hooked up both poles to the ...
30
votes
6answers
459k views

What causes battery terminal corrosion?

I put a new battery in my car about 8 months ago. After a problem starting a couple days ago, I found that there was massive corrosion under the battery terminals, so I cleaned them out and ...
23
votes
4answers
12k views

How do I test my car battery?

My car still starts fine but when I turn off the car (just the motor . . the key is still in and "on") I noticed the headlights dim to almost off. It's and older car and the headlights don't turn off ...
23
votes
8answers
10k views

Static electric shock as I leave the car

Now this has started to "interfere with concentration". It is happening when i am getting out and trying to close the door. I feel a static shock as i touch the metal part of the door as my foot ...
22
votes
4answers
2k views

Are there requirements for building a car-PC and it's software?

I am currently rebuilding a car as a hobby. As a part of it I am planning on building in a car PC with custom software for some multimedia usage, navigation and some diagnose usage. I know there are ...
21
votes
9answers
93k views

Battery drains by itself when vehicle is parked (parasitic draw)

A 1998 Jeep Grand Cherokee has gone through 3 batteries in the last 3 months. While they have all been replaced by warranties, it'd be nice to get the problem solved permanently. I've tested the ...
21
votes
4answers
5k views

Replace car batteries with capacitors?

I recently watched this video on YouTube which basically shows the guy replacing a larger capacitors with some smaller capacitors which he had bought. The larger capacitors were actually in place of a ...
20
votes
3answers
6k views

Should I replace fuses as a part of regular maintenance?

I've been having a few problems that might be electrical in my car. Seeing as mechanics always want to replace parts first, I'm having to diagnose this problem myself. It seems like replacing all ...
20
votes
4answers
54k views

Can a weak battery destroy an alternator?

I've heard a story that a weak vehicle battery can destroy an alternator or cause an alternator to fail early. Is this true, or is it largely fiction?
19
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6answers
25k views

Adding a additional battery to car

I have purchased a brand new Toyota Innova. I need to install a a mac mini, 2 laptops and make this car a mobile office. I need to know if I can install another car battery in parallel, and will ...
18
votes
4answers
5k views

What can I do to combat wire embrittlement?

I live in a very hot climate where temperatures regularly touch 45 deg C and the heat in the engine bay area means that under-hood wires, especially the thinner ones, endure high levels of thermal ...
18
votes
7answers
10k views

2000 Jetta runs rough, shudders on cold start only on wet days.

This is an issue I've had off and on for, embarrassingly, at least a year: On misty or wet mornings, everything starts out fine but, a few minutes into the drive (like clockwork. I even know the ...
16
votes
7answers
62k views

Should negative trickle charger clips be attached to the battery negative terminal, or ground?

I'm trickle-charging a car using direct connections to the battery. I thought this couldn't be simpler: ventilate, unhook the battery, connect the positive first, then the negative, then turn on the ...
16
votes
4answers
11k views

350z cranks won't start

2003 350z cranks but won't start VQ35DE / FIXED * partially [ Stock / DC intake / Straight pipes ] (11/11/2016) My Cousin is a certified mechanic and took over the repair! -Car idle rough and ...
15
votes
8answers
8k views

Why don't I get shocked constantly?

Noobie question here; NOTE: I don't understand electrics much. If a car's electrical system grounds to the bodywork (usually to the negative terminal) so that the electricity flows through the metal ...
15
votes
3answers
1k views

Multimeter - Basic Functionality and Howto

Multimeters I'm looking for some responses regarding multimeter basics for the site tag-wiki to point OP's at when we want them to use one. The question is; What are the basic functions of a ...
14
votes
2answers
4k views

Why put copper in between battery contacts and clamps?

We have bought a used Toyota Yaris. Yesterday I allowed my kids to play in the car, and they discharged the battery... So I went to take it out to charge it up and I found pieces of a copper and ...
14
votes
6answers
21k views

Can I jump start one car with two other cars in parallel?

If I'm in a pinch, and I have a small car that can't put out enough cranking amps to start a bigger one, could I connect two cars in parallel to start the bigger one? Will it mess up the alternators ...
14
votes
5answers
9k views

Why is a 12V outlet that provides 120W protected by a 20A fuse in my 2015 Forester?

In my 2015 Subaru Forester, the 12V power outlet in the center console says that it is designed to supply loads that draw a max of 120W. To me, this would mean that there should be a max of 10 amps ...
14
votes
5answers
858 views

How do you test analogue electrical circuits?

When trying to diagnose problems with conventional analogue electrical circuits, such as lights, speakers, heated rear windows, etc, as well as short-circuits and unexplained current draws, it can be ...
14
votes
4answers
103k views

What is the BCM (Body Control Module) in a car?

I own a Fiat Grande Punto. Recently I was told by the authorized auto workshop that the BCM in my car has failed and needs to be fixed. So I have two questions regarding this: What is the BCM and ...
14
votes
1answer
73k views

Do I have to rely on wire color to correctly wire up an O2 sensor?

It seems that everyone and their grandmother has a different color-code convention for 4-wire O2 sensors, which complicates matters when one is trying to wire up a replacement "universal" O2 sensor. ...
14
votes
1answer
675 views

How can I tell which parts of my car are “By Wire”?

I've recently purchased a manual transmission 1.5 litre Honda Mobilio. It is claimed to be a drive by wire vehicle and I assume it really is, but I don't know how to tell if a car is drive by wire. I ...
14
votes
2answers
2k views

How to determine exactly what's wrong with my alternator?

My 98 Mazda 626 GF 2L uses an 80 amp fp34 A2TB0191 alternator with an internal voltage regulator. I did a little test where it I turned on the bright lights, AC, radio, rear defogger and opened the ...
13
votes
5answers
210k views

How do I determine what type of jumper cable I should carry?

I recently bought a used car, and it didn't come with any jumper cables, so I'm going to buy some. I briefly looked around at a store and online, and there seems to be a wide variety of prices and ...
13
votes
5answers
32k views

'09 Chevy Malibu - No Crank, No Start - Heavy Troubleshooting Already Completed

Answer: Turns out the computer was shot, entirely non-functional. Swapped one out and the car started right up. For future readers: The computer is a likely cause if the vehicle has power, yet ...
13
votes
1answer
39k views

Why do the lights flicker when I accelerate?

I have a 2003 Ford Focus. Recently, I've noticed that when I accelerate (step on the gas), all the lights on the car flicker. This happens to both the dash lights in the car and the headlights ...
13
votes
2answers
5k views

Car stalls/dies suddenly while driving and is not starting again

I own a Indian Make TATA INDICA Ev2 (CR4) Turbo Engine car. I did rebore recently and the mileage was 130,000 KMs. After rebore first service of 3000 km is successfully completed and now I'm facing a ...
12
votes
3answers
14k views

Car won't start, horn won't honk, headlights won't come on, what could cause this?

Vehicle: 2005 Honda Accord LX 2.4L FI DOHC 4cyl Symptoms Car wouldn't start today. In the past had occasionally had it hiccup before starting but that was the only indicator of problems. No ...
12
votes
2answers
17k views

How do you remove or even get to the car battery on a 2012 Honda Odyssey?

Summary How do you get to the battery on a 2012 Honda Odyssey, given that it is blocked by some type of intake tube**? **Edit: this used to say exhaust but I changed it to intake tube, given the ...
12
votes
4answers
2k views

Is 60/40 solder fine for splicing wires that have to endure hot engine bay temps?

I need to splice the pigtail connectors from my old O2 sensors onto the new O2 sensors since the new connectors have a different shape. As the sensor is right behind the engine and will experience ...
12
votes
6answers
60k views

What are the tradeoffs for positive vs. negative ground?

I just got a classic Ford 8N tractor running again. Someone trying to be helpful flipped the battery around, connecting negative to ground. This made the engine crank backwards! So I had spark, ...
12
votes
2answers
507 views

Peculiar Interior Lighting Issue

Recently a friend of mine was driving a VW Fox (not new, I'm not sure what year but it was certainly 5+ years old) home in the dark with the lights on. Strangely, after a minute or two of driving all ...
11
votes
7answers
37k views

Fuse box above battery melting

I have a 2001 VW Beetle which has a nasty habit of melting the above battery high voltage fuse box. I've replaced it three times already and replaced the alternator as well, but I'm at a complete loss ...
11
votes
3answers
21k views

When should I disconnect the battery to stay safe during repairs?

I am planning to do some car fixes and want to know what precautions I must follow in order to make it safely. Specifically, I'd like to know is for what kind of work, the battery should be unplugged. ...
11
votes
3answers
8k views

How to upgrade a motorcycle battery to a bigger AH battery?

My motorcycle (honda CBF150) came with a 12V 3AH battery. I want to change the stock 35w headlight to a higher power one and connect them directly to the battery (the stock ones are not, and they ...
11
votes
3answers
307 views

How do I make all of this work together?

I have a friend with 1988 Jeep YJ. I'm not sure if this question is more appropriate for here or for Electrical Engineering. We want to mount this blender with an AC motor in it. I think it's 110 ...
11
votes
2answers
3k views

2007 Hyundai Elantra - Car beep when I lock the door no longer working

I got in a minor accident the other day. Cosmetically my hood was a little crumpled and the grill cracked. Functionally the only thing not working is the wireless lock beeping feature. Is this ...
11
votes
4answers
25k views

How to assess battery charge level and alternator performance?

What diagnostics can be done to to assess battery charge level? I'm interested both in one-off tests like can be done in car service and also continuous monitoring during normal use. Car panels ...
11
votes
1answer
896 views

Locked out of my accord

My 2013 Honda Accord EXL the battery died the key fob won't open the door and neither will the manual key what can I do
10
votes
5answers
11k views

How stable is voltage in a 12V car outlet?

I want to use a Mini-ITX PC board in a car. I plan to use the 12V "cigar" outlet or take the 12V elsewhere, but from the same 12V source that is dedicated to be used for user devices within a car's ...
10
votes
5answers
47k views

How can a fuse drain a car battery?

My car battery drained itself after a week of not being used. I was researching how to identify the cause, and saw a comment under this article saying: What if I am not detecting a reading but the ...
10
votes
5answers
7k views

Low voltage at reversing light socket - is it the switch? What else could it be?

The car has a single reversing light in the bumper. The bulb doesn't light at all (tested, also tried spares). Measuring the voltage at the socket I get around 9V with no bulb in the circuit (with ...
10
votes
4answers
6k views

Do cars ever use electric water pumps?

I saw this question in the cue recently. I know of no cars that are in production that use electric water pumps. I am assuming that it's continuity issue related to failure rates and engine damage ...
10
votes
2answers
79k views

Lots of sparks and heat when jump starting a car

I just tried to jump start a friend's car. When I connected the jumper cables, there were a lot of sparks. They were connected for nearly 30 seconds and I noticed a lot of heat and smoke coming from ...
10
votes
3answers
1k views

Why do attempts to charge a flat car battery with an electronic battery pack give results as if there's a short circuit?

I'm not having a good weekend - car wouldn't start, even when jump started using a conveniently placed 12v generator battery (almost identical to this question, I suspect dodgy cabling to the starter)....
10
votes
3answers
8k views

Car Battery Dying Overnight - Disconnected

I have been having trouble starting my car (needed to jump it twice, once in the morning, and once in the afternoon). Sometimes it would make a clicking noise when trying to start or it would be ...
10
votes
2answers
7k views

2003 Suzuki Katana GSX600F - No Start Issue

So I recently purchased this motorcycle from a third party. 2 days ago it would start up fine and you could ride it. The guy I brought it from said the battery was acting cranky so you should change ...
10
votes
1answer
1k views

Motorcycle Headlight Conversion

I've decided to install a new headlight on my bike. The current setup is two bulbs, one is on for low beam and both on for high beam, with two wires going out of each (h11?). Here is a short video of ...
10
votes
2answers
2k views

Suzuku Katana does not start after an accident

I have a Suzuki Katana GSX600F. After an accident I was in, I rode the bike home and all was fine except a little cosmetic damage. In rainstorm it tipped over and after picking it up and trying to ...