Concerning the main electrical system of a motor vehicle or internal combustion engine. Consider a different tag for radios and other such systems.

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18
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9answers
49k 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 While they have all been replaced by warranties, it'd be nice to get the problem solved permanently.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 ...
18
votes
3answers
2k 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 ...
16
votes
5answers
70k 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 ...
15
votes
6answers
6k 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 ...
13
votes
4answers
252 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?
13
votes
1answer
87 views

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

I've recently purchases a manual transmission 1.5 Honda Mobilio. Which 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 am a ...
12
votes
4answers
30k 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 ...
12
votes
1answer
10k 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. ...
11
votes
3answers
178 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 ...
10
votes
3answers
539 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 ...
10
votes
2answers
492 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 ...
10
votes
2answers
110 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
3answers
853 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 ...
10
votes
1answer
184 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 ...
10
votes
1answer
271 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
1answer
227 views

Are there downsides to making an accessory socket always live, if accessories are removed when not in use?

In some cars, the power line from the battery to the accessory outlet (aka cigarette lighter socket) is always live. In others, it's off until ignition. It seems pretty much random which cars are ...
10
votes
1answer
80 views

Engine starter just won't stop starting

I have a 98 Toyota privia and upon starting it the starter just keeps going. This only occurs in drive and neutral. The vehicle also starts in any gear. When I start in park the starter keeps spinning ...
10
votes
1answer
4k 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 ...
10
votes
2answers
73 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 ...
10
votes
1answer
161 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 ...
9
votes
6answers
9k views

Noise in stereo that changes pitch with engine RPM

This is a question of curiosity. I have a '98 Acura Integra, a cheap car stereo with a 3.5mm aux in, a cheap inverter and a smart phone. If I have the smart phone audio hooked up to the car stereo and ...
9
votes
3answers
271 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 ...
9
votes
1answer
204 views

Is it possible to repair an intermittent or flaky turn signal flasher relay?

Ouch, a new turn signal flasher relay is $65 at the local parts shop. Is it possible to DIY a repair of such a flasher relay?
9
votes
4answers
9k 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 ...
9
votes
1answer
71 views

2000 Suzuki Grand Vitara 4x4 flashing

Whenever i engage my 4x4, the 4x4 light flashes. It didn't used to do this. Its annoying watching it flash. Any ideas what could be causing it to flash?
9
votes
1answer
127 views

What is this extra light on my headlights?

I own a 2006 Mazda 6 Luxury Sport in Australia, and the front headlights have 4 lights on them: It also has a fog light, which is not featured in this photo (but will be visible in later photos). ...
9
votes
1answer
372 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
9
votes
1answer
320 views

A most intriguing cold-start misfire mystery

I'm trying to help a friend out with a CEL on his 2009 Merc GLK 280. Hooked it up to an OBD2 reader and retrieved a single code: P0300 - 'Random/Multiple Cylinder Misfire Detected', via the 'OBD ...
9
votes
1answer
58 views

Why is one of my interior components electrified?

I have a 2007 Nissan 350Z and there is a trim bar inside of my car that feels electrified. I even touched my tongue to it (please, I know) and I can feel electricity. It's similar to if you have ...
8
votes
5answers
1k 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 ...
8
votes
3answers
594 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)....
8
votes
3answers
297 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 ...
8
votes
2answers
192 views

Shutting off fans at highway speeds

On my vehicle (92 Civic) and most others I've seen, the condenser fan comes on whenever the A/C clutch is engaged. This seems like a waste of electricity (and thus fuel) when cruising at 60-75 mph, ...
8
votes
2answers
412 views

Will a ground to the frame work properly if the bolt is powder-coated?

Would there be any electrical issues if a grounding point had a bolt welded and powder-coated or is it better to drill a hole, weld a nut to the frame and then powder-coated?
8
votes
3answers
520 views

Driving electric cars through large pools of water

The state of California is expected to be hit by a large storm in the coming days and there are frequently clogged drains in my town. I have an electric vehicle that seemed to handle driving through ...
8
votes
4answers
323 views

Standard mounting screw for vehicle relay

I have a MAH-112-C-4 relay that is supposed to be capable of working as a relay for fog light, head light, battery control, oil pumb control, fan control, air conditioner, harness. There is a ...
8
votes
2answers
147 views

Old starter clicked, wont turn over engine. New starter wont even click - no noise at all

My old starter would click, but not turn the engine over. I got a brand new starter and installed it. The only two wires connected to the starter are completely different and can only be fit in the ...
8
votes
2answers
81 views

Two Fuel Pumps died

Already having replaced 2 fuel pumps, both died. Seems to have a problem in somewhere (alternator, battery, electricity) or I have no luck for fuel pumps. The last one, last 6 months, before died ...
8
votes
1answer
73 views

Testing specific wires in harness cable

I want to do some electrical mods like adding a push/pull switch to my truck' tailgate to wire into my door ajar light to let me know if it is open along with splicing an electrical tailgate lock into ...
8
votes
3answers
716 views

2007 BMW Z4 won't start when my phone is plugged into the cigarette lighter plug

Sometimes when my cell phone is on charge in my 2007 BMW Z4 before I start it, nothing happens when I turn the key. The car is acting like it, as if I did not have the clutch pushed in - the key ...
8
votes
4answers
20k 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, ...
8
votes
1answer
80 views

Suzuki 2004 sv650s wiring

I got a 2004 sv650s Suzuki when I turn the key on the fuel pump does not come on and the CHECK light comes on on the dash. All the lights come on and the starter button does not work.All the fuses are ...
8
votes
3answers
233 views

Good car for full electric conversion

I am just going into my final year of mechatronics engineering, and as a project for my spare time I am looking to convert a car to fully electric drive. At the moment I am also toying with the idea ...
8
votes
1answer
157 views

Why does my new tail light keep blowing the fuse?

I have a 1972 Honda CB350F and I got the new tail light from DimeCity. I think it was called the Buffalo style Medium tail light. The tail light turns on and works fine when I switch on the headlight, ...
8
votes
1answer
262 views

Finding And Fixing A Short

Make: Chevy Model: Cavalier Year: 1993 (old I know) Symptoms Turn signal no longer works. The lights do not come on, and there is no "ticking" sound. New Fuse for signal blows as soon as the car ...
8
votes
1answer
150 views

Disconnected wires near battery in BMW e46

I noticed a disconnected wire dangling next to the battery in the trunk of my 2005 BMW 330ci. It was actually a red and blue wire that veered off from the thick red one in the middle of the image. ...
8
votes
1answer
321 views

Battery Light Won't Go Off Since Changing Battery

I just changed the battery on my 98 Mazda 626 and now the battery light comes on and stays on after starting the car. I checked the battery and it's reading 12.8v with the engine off, and 13.8 with ...
8
votes
1answer
53 views

No power but battery, alternator, and connection are good

This involves a company truck, 08 Chevy Silverado. I am not a mechanic or DIY nor do I play one on TV. The problem I am having is that every 2 or 3 months this truck will not start and completely ...
7
votes
3answers
165 views

What are some typical maintenance things that every owner should do regularily?

Right now I just get a car wash every month, and my oil changed and whatever is included in that. Usually just a quick "inspection". Is there anything else I should be doing for my car? Or also, is ...
7
votes
4answers
2k 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 ...