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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15
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8answers
42k 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 While they have all been replaced by warranties, it'd be nice to get the problem solved permanently.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 ...
14
votes
5answers
40k 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 ...
10
votes
3answers
24k 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 ...
9
votes
2answers
308 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 ...
9
votes
3answers
804 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 ...
9
votes
1answer
46 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 ...
9
votes
1answer
175 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 ...
9
votes
1answer
3k 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 ...
9
votes
4answers
5k views

2000 Jetta runs rough, shutters 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 ...
9
votes
1answer
191 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 ...
8
votes
1answer
146 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 ...
8
votes
4answers
7k 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 ...
8
votes
3answers
194 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
256 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 ...
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 ...
7
votes
2answers
208 views

2004 VW Passat B5 Cigarette Lighter Broken - Common Problem

The problem I have been having with my VW Passat was that my cigarette lighter was not working in the car. It is the only one in the main part of the car (there is another one in the boot) and it ...
7
votes
2answers
700 views

My mazda milenia wont rev past 2500 rpm

So I just recently bought a 2000 Mazda Milenia s Millennium edition,and on my first day out with it, I experienced a very unusual problem. After about 20 minutes of driving the car wouldn't rev past ...
7
votes
2answers
5k views

Can an engine stop from a bad battery?

The car is a 2005 Toyota Corolla CE. Its engine is the 1ZZ-FE, a 1.8L straight four that runs on gas, not diesel. The alternator is stock, and tests out just fine on the multimeter in both voltage ...
7
votes
5answers
1k views

Can hooking up jumper cables incorrectly damage the electrical system of the receiving vehicle?

Our Jeep was having problems turning over, so we called a tow truck driver. He connected the jumper cables incorrectly, starting a small fire on the battery box. After the fire was out, the Jeep no ...
7
votes
1answer
42 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 ...
7
votes
1answer
136 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, ...
7
votes
3answers
3k views

Does idle RPM increase when there is heavy load on the electrical system?

I am thinking about installing a 500w halogen (HDX brand) on the roll bar in my jeep as the dome light because often I work in the back when it is dark or when I would like more light. The 500w light ...
7
votes
2answers
87 views

Why do the batteries on some cars need to be hot-swapped?

By "hot-swap" I mean ensuring that the new battery is connected in parallel to the old battery while the old battery is removed and the new one is installed in its place. The idea is to ensure that ...
7
votes
4answers
15k 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, ...
7
votes
3answers
46 views

2005 Toyota Corolla intermittant battery drain when not running

I have a 2005 Corolla CE with manual transmission. About one month ago the car would not start, and the battery was discharged to about 8.5V. Car had been not running for a couple of days but nothing ...
7
votes
1answer
139 views

Diode selection or “Engine Running Only” electrical source on 1965 Mustang?

I am working with a 1965 mustang and have added heated seats. The seat heater wiring does not have a latching circuit and is controlled by a SPDT Hi/off/Low switch. In an effort to only allow the ...
7
votes
2answers
34 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 ...
7
votes
1answer
246 views

GPS dashboard mount replacement?

When I bought my car, they were doing a promo and shipping a Garmin GPS with it. Thing is, the GPS came with a nice mount, fixed to the dashboard. This was great, because it meant no wires going ...
6
votes
5answers
245 views

Charging circuit

I have a motorhome and tow my car behind. Since I have to leave the car in accessory mode so the steering wheel is unlocked, the battery doesn't last a long time. I want to run a DS line from the ...
6
votes
5answers
6k 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 ...
6
votes
3answers
157 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 ...
6
votes
5answers
40k views

Car won't start or stay running after a jump

I have a 2004 Kia Spectra 1.8, I have replaced the spark plugs, the alternator, and my battery is only about two months old. The car will start after a jump but it has to sit for about 10 minutes ...
6
votes
4answers
3k views

Why does my car scream on cold start?

My 1988 Subaru XT6 2.7L engine screams at me on a cold start then it will stop and then do it again when I take it out of park, but then it stops. Also, my car is losing antifreeze. Any ideas why?
6
votes
3answers
3k views

How to amplify car speakers without stereo?

I have a 1980 VW Dasher with its original speakers but no radio. It has an unusual (erroneous?) electrical configuration where most accessories (e.g. lights, cabin fan, etc) still run even with the ...
6
votes
2answers
7k 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 ...
6
votes
2answers
2k views

Why are my wires melting together?

I'm currently neck deep in an eletrical shortage issue with my BMW 316i. I found the wires that are blowing my fuses, and it's bad. Like at least 5ft of 8 or more wires fused together behind my ...
6
votes
1answer
35 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?
6
votes
2answers
77 views

Battery and Alternator Pass Test - 2003 Mustang GT

I have a 2003 Ford Mustang GT, I had the battery tested and it will take a jump and start up so naturally I am thinking the alternator is bad. I take the alternator out and have it tested 3 times and ...
6
votes
1answer
8k views

Why would my electrical systems cut out when I brake?

So I told this little story to the dealership service department, and they were baffled. Never heard of anything like it in ten years, said they'd have to examine it very closely. Here's what ...
6
votes
2answers
576 views

How to detect a failing car alternator..?

Is there some way we can predict that the car alternator is about to fail in order to avoid a discharged battery situation on the road.. Although it will slow the sound of horn and will dim the ...
6
votes
1answer
3k views

What current is “normal” for constant battery drain (not parasitic)

I'm having some problems with battery going dead sometimes, and I noticed that there are some small sparks after disconnecting the battery for a few seconds and then reconnecting again. It is not big ...
6
votes
1answer
52 views

Help with Strange Intermittent yet predictable parasitic battery drain?

I'm having an issue where while testing circuits for the offending drain, I will see NO drain for about 30 seconds and then a 6-9 amp drain for about 10; rinse and repeat. Anybody have an idea what ...
6
votes
1answer
44 views

Can I Mount auxiliary lights for Hero Honda Passion 2002 bike?

I am having a Hero Honda Passion 2002 model bike. The head light is very low and it works on engine power not on the battery, due to this riding bike in no light area with lots of ups and downs are ...
6
votes
2answers
1k views

Bmw E46: strange problems with automatically closing windows and broken light warning

I have had a couple of strange problems and I can't really make sense of it. When I parked the car, I locked the doors as always with the windows closed (I am absolutely sure about this; it was ...
6
votes
1answer
43 views

Battery light on after new alternator

Car: 2003 Honda Civic Si G1Wh dash cam, 400w amp, 4300k HIDs My alternator failed badly (stereo cutting off), no battery light. Replaced it with a reman Duralast, battery light is on. It shows 14.5v ...
6
votes
3answers
3k views

AC blower won't turn on after replacing battery

I have a U.S. 2011 Volkswagen GTI. After the car wouldn't start (starter would crank but engine would not turn on) I decided it's probably time to replace the battery, and did. Car starts fine, but ...
6
votes
0answers
38 views

Fiat Siena EL 2001 was starting but jerking very bad whist running

Fiat Siena EL 2001 model It has a starting problem, I'm really desperate to get it running again, please help. The car was starting and running but was jerking very bad when in 2nd gear. The ...
6
votes
0answers
542 views

How to reach the fuse box from Mk1 Golf Cabriolet?

On an 91 Golf Cabriolet (Mk1), the fuse box is hidden behind the knee bar, and has no access hatch. I need to have a look at the top of the fuse box to see if fuse 19 (indicators) is broken. Is there ...
5
votes
2answers
76 views

Removing a car battery - order of wires explanation

Q1: When one removes a car battery, why does one start with the minus wire? Is it because if we remove the plus wire first it may touch the body of the car and close the circuit, causing a ...
5
votes
4answers
334 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 ...