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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12
votes
6answers
29k 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 While they have all been replaced by warranties, it'd be nice to get the problem solved permanently.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 ...
9
votes
2answers
17k views

What is 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 that - What is a BCM and ...
9
votes
3answers
708 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
4answers
3k 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 ...
8
votes
4answers
4k 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 ...
7
votes
2answers
584 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
1answer
123 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
2k 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
1answer
235 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
1answer
79 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 ...
6
votes
5answers
27k 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
2k 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
674 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 ...
6
votes
2answers
5k 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
1k 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
5k 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
467 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
4answers
9k 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, ...
6
votes
2answers
854 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
3answers
344 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 ...
5
votes
3answers
2k 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 ...
5
votes
2answers
1k views

Have tow ball but not electricity for a trailer

I have a Toyota Camry 2004. When I just bought it, I have noticed that it has a tow ball. I didn't really intend to use it but now it could really help me to move few things around with a trailer I ...
5
votes
3answers
873 views

How do I diagnose opened door indicator problem on a Honda Civic 1.8Vti Aerodeck

The opened door light indicator flashes at random rate when I drive. This also randomly triggers the alarm system that I had to disconnect. I have removed every door switches. No differences. ...
5
votes
2answers
3k 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 ...
5
votes
3answers
4k views

2007 Nissan Armada power window fuse location

According to the fuse block diagram, there is not a dedicated fuse for the power windows. Anyone know if the power windows are on another fuse? Front drivers side window will not go down and switch ...
5
votes
3answers
565 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 would if I did not have the clutch pushed in - the key ...
5
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 ...
5
votes
1answer
535 views

Should I disconnect the battery when working on my instrument cluster

I am going to be changing a few bulbs on my Opel Astra's instrument cluster. Part of the process involves disconnecting the entire cluster from the wiring harness and obviously replacing it when done. ...
5
votes
1answer
2k views

How can I diagnose gradual electric power loss in a VW Golf Mk5?

I'm experiencing loss of electrical power to my Mk5 Golf. It seems to happen mostly when the car hasn't been run for two or three days. We changed the battery a few months ago. More recently, there ...
5
votes
3answers
509 views

93 Nissan Sentra SE-R, replaced alternator voltage still low

My car died while I was driving it, but I can put the battery on a charger (or from another car, with jumper cables) and get it running albeit for a short period of time. I put a multimeter on the ...
5
votes
2answers
4k views

Manual horn switch

what are the pitfalls or things to look out for when manually wiring a switch from the battery to the horn? Some background: I just moved to texas where they require vehicle inspections. My horn ...
5
votes
2answers
2k views

Daytime running light failure — one side only

I have a 1991 Miata. It's a Canadian vehicle, and so is equipped with daytime running lights. Recently, I've noticed that the passenger side light is not working as a DRL. The driver's side light ...
5
votes
1answer
194 views

Should I replace this stator? (2007, Suzuki, DL1000)

I opened my stator case to inspect what I thought was a bad stator. I discovered the following issues with my magnets: Broken Magnets: Cracked Magnets: Not sure if I need to replace stator ...
5
votes
2answers
2k views

Chronic ignition problems with 1996 Suburban, replacing distributor cap makes it go away

I'm trying to diagnose an ongoing ignition problem with a 1996 Chevy Suburban. Sometimes it won't start, and the previous owner said this happens regularly, and every time the problem occurred, ...
5
votes
1answer
100 views

No spark on my new motorcycle

I recently purchased an 81 Suzuki GS450L, my very first bike. I'm not getting a spark. When it dies, it does so silently. No backfire, sputtering, etc. My first thought was that it had aftermarket ...
5
votes
4answers
410 views

Can an O2 sensor cause faulty spark plugs on driver side only when the spark plugs were just changed?

I took my truck (2006 chevy silverado 5.3l v8) to chevrolet dealership due to the fact that it kept sputtering then dying. The check engine light was on the whole 9 yards. The fuel pump has been ...
5
votes
1answer
76 views

Knock sensor ground and dieletric grease

The knock sensor for my 2001 Subaru Outback grounds through the engine block. I've seen various advice about whether to put dielectric grease on the underside (where the grounding takes place). Some ...
5
votes
1answer
196 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 ...
4
votes
4answers
6k views

What is the best overall ODB2 scan tool?

There are a number of different ODB2 scan tools out there, some PC based, some standalone units, some more for tuning and some more for diagnosing problems. What are the different features that these ...
4
votes
5answers
10k views

Charger doesn't stay put in cigarette lighter outlet

The cigarette lighter outlet was never designed to be an electrical outlet the way it's commonly used today. Even so, I've yet to find a plug for charging USB devices that fits and doesn't fall out. ...
4
votes
5answers
11k views

Keeping radio/stereo unit powered to save pre-set preferences?

In my previous cars I could save certain radio stations, volume levels, etc. on my stereo and they would stay saved (unless the battery went dead). I'm using the same stereo head unit in my latest ...
4
votes
2answers
648 views

Upgrade to HID lights in a Jeep Wrangler

I would like to upgrade to HID lights in my 2008 Jeep Wrangler. The stock lights aren't bright at all. My question is, since this would be an aftermarket upgrade, what am I looking at here? Is it ...
4
votes
1answer
3k views

When I set the air flow to Defrost, it turns on the A/C?

On a 2001 Honda Civic. Having the temp dial to HOT. When I turn the air flow dial from FRONT to Defrost (windshield), it turns on the A/C button and the A/C motor kicks in also. It just started doing ...
4
votes
2answers
2k views

12v Acc/Switched vs 12v Always On

I am currently designing a part that should always be on when the key is turned to On/Acc, and only sometimes on when the key is set to Off, or removed. My car is a 99 Camry, but I have a good ...
4
votes
1answer
121 views

Is it necessary to have the good car's engine running when jumpstarting

When jump-starting a vehicle, one first connects the positive and negative terminals between the two cars: positive to positive and negative (good battery) to a bolt head on the vehicle with the dead ...
4
votes
2answers
5k views

Can cold weather cause TPMS sensors to malfunction?

I just bought a new 2011 Honda Fit and while driving it home from the dealer, I noticed that a little light on the dashboard was on that said "TPMS". When I got home, I consulted the owner's manual ...
4
votes
1answer
260 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. ...
4
votes
2answers
55 views

Low beam headlights failing every 3-4 weeks

I have Volvo XC90 2006 and for the past few months every 3 - 4 weeks changing low beam light. Last time even did not last 5 days. Any recommendations why this light is failing?
4
votes
1answer
49 views

Wires Coming Out Of Center Console

I bought a 2011 Ram 1500 about 6 months ago. I removed the rubber liner for a small compartment in my center console. When I tried putting it back I realized it would not go down all the way and found ...
4
votes
3answers
8k views

OBD-II reader/scan tool that can also diagnose air bag light

Is there an OBD-II reader/scan tool that can also diagnose air bag warning light? My 2004 Honda Element EX has a red air bag warning light that recently has turned on. The nearest Honda dealer wants ...