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
votes
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 While they have all been replaced by warranties, it'd be nice to get the problem solved permanently.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 ...
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 ...
5
votes
1answer
8k views

How should the lights for a trailer be hooked up?

I have a tent trailer and the lights don't work right. It has a 4 wire connector to my car but one of the wires on the trailer connector was worn out and probably not working. So I got a new 4 prong ...
9
votes
3answers
180 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 ...
4
votes
3answers
14k views

Low beam headlights don't work, High beam headlights do

The vehicle is a 2003 Chevrolet Trailblazer. The low beams aren't working. High beams are. The fuse is perfectly fine (tested and swapped out). The bulbs are fine too. A mechanic told me it could be ...
3
votes
2answers
495 views

Writing CAN Messages

I want to know what should I write with the CAN ID to send it to ECU. I am using ELM327 and Raspberry Pi with all connections to OBD-ii. initially for sending general PIDs to the ECU through ELM327 ...
9
votes
1answer
192 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 ...
4
votes
2answers
717 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 ...
2
votes
1answer
46 views

electric windows broken

Can anyone help just got home and have gone to do my electric windows up and non of them will go up I had an issue with the passenger side switch not doing the window up but would do it down but now ...
2
votes
2answers
112 views

1987 Yamaha FZ700 headlights not working

I recently bought a 1987 Yamaha fz700, and the owner said the headlights didn't work, and I can't figure out what's wrong. We checked some of the wiring out, and the bulb connectors have no power ...
1
vote
1answer
403 views

'99 Audi A4 seat belt warning sign

I've had this seat belt warning light on my dash for a few weeks now. My dealer says the wiring to my driver seat is gone and replacing it could cost close to 800 USD. Is there a better option?
5
votes
1answer
4k 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. ...
5
votes
1answer
3k 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 ...
4
votes
2answers
64 views

Start a circuit or device when you insert key in car ignition

I want to start a circuit in my car when I insert my key in car ignition and let it turn off when the key gets removed. I have Honda Civic 2007. Can someone just help me out as to from where do I take ...
4
votes
1answer
145 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 ...
3
votes
6answers
7k views

2006 Kia Sedona intermittently not starting

What could be causing my (non-)starting issues? Occasionally (once every two weeks or so) when the keys are inserted and turned to the start position, nothing happens. No noise, no dome lights dimming ...
2
votes
3answers
324 views

Is my mechanic ripping me off?

My 2002 ford focus (built after may 23) died and the AAA and tow guy both said that it needs a new fuel pump. Anyway I went to the mechanic and he said it'll be 350 for the pump and 200 for labor. I ...
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 ...
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, ...
5
votes
2answers
6k 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 ...
4
votes
1answer
528 views

Is this repair estimate for misfiring and fuel trim on a '98 Mercedes reasonable?

Just got a '98 Benz ml320 and two days later it cut off on me, twice, within about 5 minutes. I took it for a diagnostic. I'm wondering how overpriced this estimate is and possible ideas of best ...
4
votes
2answers
182 views

If I were to convert a gas powered automobile to an electric car, would a difference in specs possibly damage the car?

I would like to convert a Mazda Miata into an electric car, I plan to remove the engine and the gearbox, and have the car be a direct drive. The motor I intend to use has twice the torque of a ...
4
votes
1answer
1k views

Windshield wipers worked intermittently then quit altogether

The wipers on my 2000 Mazda Protege recently quit working. It wasn't an all-of-a-sudden thing, though. Every so often over the last few weeks they would stop for a few seconds, then start again. ...
4
votes
6answers
18k 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
2answers
1k views

Suzuki GSXR600 (K7) - Burned regulator/rectifier

I have managed to completely fry regulator/rectifier on my Suzuki GSXR600 (K7). I suspect that it happened when I blindly splashed into a big water pond, so some water probably got on connector. Thing ...
3
votes
1answer
214 views

VW Golf 2001 Mk4 Diesel ASR Engine Problem

I've spent a crazy amount of money on my car lately and I still have the same problem. I've replaced the: Catalyst Converter Radiator Starter Motor EGR Valve Track Rod ends & Wheel Bearings ...
3
votes
0answers
180 views

06 scion Tc turns over then shuts off in two seconds

My fiancé drove the car with no problems this morning. After work she realized she left an interior light on which killed the battery. She got a jump from a car and charged the battery up a bit. The ...
3
votes
2answers
2k views

Ford Focus - bad starter?

Car 1.6L Ford Focus estate, made in 2000. It is right hand drive, although I doubt that matters. Issue When the ignition key is turned from "On" to "Start", there is a click (sounds like a relay ...
3
votes
1answer
215 views

89 jeep cherokee will run but when i turn it off and try to restart it the battery is dead

The battery is still good and the motor will keep running when you disconnect a terminal. Can my alternator be bad? If not I'm also thinking a dead short? What is the best way to find out?
3
votes
7answers
38k views

Unable to start the vehicle depending on how long it has previously been driven

I have a Citroen C3 which is giving me a headache. The problem is a recent one, and is basically that I can't start the car. The strange thing is that the problem only surfaces when I've been driving ...
2
votes
1answer
629 views

Series of troubling electrical problems in my '07 Mazda 3. Any ideas?

I'm having a series of what I will call electrical problems with my Mazda 3. I'm not sure if they are interrelated and wanted to get some advice or ideas from you guys. Apologies in advance for the ...
1
vote
0answers
34 views

Merdeces stalls after 30sec-1min, and battery warning light is on [duplicate]

I've got an old but low mileage Mercedes and This problem puzzles me. The car stalls after a short time(30 seconds to 1 minute) after start up and the battery warning light on the dash lights up. I ...
1
vote
1answer
145 views

Battery high voltage

I measured my "cigar socket / outlet" with a multimeter. Instead of 12v it had 19v. Is this normal? Is it my voltage regulator, alternator, battery that has problems? Car: Peugeot 307, 2.0 XSI 2003 ...
0
votes
1answer
46 views

Calculate car battery life using OBD parameters

I want to calculate the battery life of a car based upon OBD2 parameters like engine load, distance traveled, Control Module voltage etc. Can anyone please guide me as to how to do this? If ...
0
votes
2answers
2k views

2001 katana won't start

2001 Suzuki Katana. Here is the story, after winter it fired up fine, just had a lag on the throttle. Pulled out air filter bike sounded like it loaded up and just died. I left it for a week. I went ...