Hot answers tagged electrical
9
The Body Control Module is a computer which controls many things in your car not directly related to the engine. Instead of large wiring looms en relais and circuits all over the car all the buttons connect to a single computer which in turn turns on the headlights, open the windows, control the central door locking, etc. A good example is the VAGCOM system ...
9
Standard digital multimeters can measure current and help you identify what in your vehicle is consuming your battery's juice. Get an electrical diagram of your vehicle and try to narrow it down by doing current measurements in the various major paths of flow. When your car is off, no (or only trace) current should be flowing. Every time the path of ...
8
Xenon headlights require different electronics to drive them, but they also need different reflectors and also a light leveling system to prevent blinding the drivers of other cars, because the HID lights are so much brighter than traditional lights.
If you look closely at a car with HID lights, with the lights shining on something in front of them, you ...
7
Apparently, this is the Mazda limp home mode. If you check that link, two common causes are:
Vacuum leaks
Bad ABV solenoids
In discussing with your mechanic, I would suggest first having them scan for codes to see what is triggering the limp mode.
7
If the battery dies whilst driving, but you can jump it off another car, you want to look at the alternator first (possibly followed by the battery, the wiring and any large loads, because either your battery is not charging or something is draining it faster than the alternator can charge it)
An alternator should give somewhere over 13 volts (often 14.5) ...
6
Sure enough, you've got a damaged wire that is shorting out the entire electrical system. So think about what happens when you press on the brake pedal, it sends power to your brake lights at the back of the car, so if one of those wires were shorting, you would only notice it when you tap the brakes.
The weird thing is, this doesn't happen very often, ...
6
I'm sure you could manage to measure the amount of energy wasted by your condenser fan, but I promise you it's statistically insignificant. If you're trying to save an amp or two or power, it would make more sense to make sure you don't have any lights on or that you're not carrying any heavy objects you don't need in your trunk.
That said, the most ...
5
Measuring the state-of-charge of a lead-acid battery is non-trivial.
The easiest way is to use a voltmeter. You'll need a digital meter with 3 1/2 digits of precision. Let the battery rest, disconnected, for 24 hours. Then measure the voltage across the terminals. According to http://www.phrannie.org/battery.html, anything over 12.60V is at least 85% ...
5
I'd check the ground strap/contact to ground from the blinker to the chassis first. Chances are there's a problem with it an it "grounds" via another bulb when you also apply the brake.
Using a multimeter, check the resistance from the ground on the bulb holder against the chassis first, then check blinker ground against both contacts for the brake light. ...
5
Most water pumps are designed with a weep hole.This is a small hole that leaks a small amount of antifreeze just before the water pump fails.Most of the time the leak is just above the crankshaft pulley.When you shut off the car the pressure in the cooling system forces some coolant out this hole and it drips onto the pulley and is transfered to the ...
5
As Bob says, formal servicing should always follow the manufacturer's schedule - Make sure to take into account any variations suggested for your location/climate/usage pattern. This should include routine things like oil and filter changes, as well as more major, but less frequent things such as timing belts.
In terms of more general checks and ...
5
If you are not familiar with the electrical system I would get a referal to a good shop familiar with BMW's. They may have seen it before or at least recognize what caused it. This a case where it must be determined if your melted wires were the cause or the result of another problem. Just installing another harness may result in the same melted wires. The ...
5
It sounds to me like a dead battery.
Depending on how accurate your voltmeter is, what you see as 12V may be 11.9V or lower. To give you an idea, an open circuit battery terminal voltage of 11.7V indicates a completely uncharged battery.
What you are describing happened to me once with a Volvo car, due to a faulty switch in the glove-box; the glove-box ...
5
You should be able to sneak a clamp on to the positive terminal, and there's an auxiliary negative (ground) terminal lug nut to clamp onto right in front of the coolant fill tube and power steering fluid reservoir.
Otherwise if you really want more room, you need to remove the intake tube (nothing to do with exhaust) by disconnecting it at the rubber ...
5
Probably not, but maybe in some circumstances. I've had 4 alternator failures in my life.
1) Toyota MR2 - Alternator diode blew up (big bang and smoke) while driving on the expressway. No prior warning. Just BANG! and was suddenly on battery.
2) Toyota MR2 - Alternator casing broke causing the alternator to bind up and jam (with loud scraping and ...
4
There are only a few parts in play here. The reverse light switch in/on the transmission, the wiring to the rear of the vehicle, the tail lamp assembly, and the lightbulb itself.
I would check the bulb first. If the filament is broken in just the right way, it can cause the flashing symptoms that you're experiencing. The part number for the bulb is 3156 ...
4
I don't know if it's common for them to malfunction, but assuming there are no leaks in your tire the pressure at 25F is about 10% lower than at 70F which is probably enough to trip the sensor.
I have a BMW with TPMS and any time the temperatures drop quickly the light comes on my dash. If the temperature drop is temporary and things warm back up later in ...
4
Here is a diagram for the basic 4 wire trailer.
Yellow - Left Stop/Turn (the big filament as you described in the left bulb)
Green - Right Stop/Turn (the big filament as you described in the right bulb)
Brown - Parking/Marker lights (the small filament as you described in both the right and left side bulbs)
White - Ground
They all hook to the ...
4
In addition to an unexpected electrical load, as covered by Captain Claptrap, there are other things to check.
The two biggest killers of lead/acid batteries are overcharging and vibration. Unless you
have the equipment and the skills to use it properly (in which case you probably wouldn't be asking) I suggest you get the charging system checked by an ...
4
First off I can say that I have done something like this, but with the ignition and not the horn - my friends ignition switch broke so we wired a bright red push button directly from the battery (well - actually a fused 12v line inside the car) to the starter motor coil - it has since worked like a champ for nearly two years.
First off - DO NOT wire ...
4
If you're looking for personal use and already have access to a laptop computer, I'd highly recommend getting a PC (or Mac, if that's what you have)-based one. You buy the hardware, generally for $100 or less (I recommend the units from ScanTool.net - the less expensive ones are fine). The biggest advantage is that you can start out with the free software ...
4
My immediate thought there was the flasher relay. Pull this out and either test it outside the car or swap it for a known-good one.
If that is not the fault, then as you rightly point out, you need to make sense of the wiring diagram... The key thing here is the wire colours. Most cars have two-colour wiring, with a main colour and a trace colour (i.e. the ...
4
http://www.wedophones.com/Manuals/Nissan/2003-Nissan-Xterra.pdf
That should help ;)
Not sure where you can find a universal wiring kit though. The aftermarket headunit should have a small diagram on it as well.
4
As your father says, car batteries are designed for a burst of power (the high-current starter motor), not a steady stream. If you're going to use a battery a a general power supply, you need to get a "deep-discharge" battery, as designed for caravans/marine etc usage.
Constantly discharging/charging a normal car battery will reduce it's life significantly, ...
4
It is partly a matter of convention and standards, and partly because positive earth encourages galvanic corrosion* of the surrounding bodywork - whearas with negative earth is is the much-easier-to-replace electrical contacts that corrode.
*Think back to school physics lessons with anodes and cathodes...
4
The first thing to check are the grounds anytime you have seemingly unrelated systems not working, working sporadically, or as I like to call it, any time you have gremlins running around in the electrical system.
Looking at the ground distribution for G202 pictured below you can see that Instrument panel cluster, and the daytime running lamp module share ...
4
This sounds most likely to be a fault in the switch in the indicator stalk - normally you have a physical linkage which keeps the turn indicator flashing while you turn a corner, then it releases as the steering wheel straightens.
I can imagine a couple of ways this could fail and allow the spring in that mechanical return to perhaps trigger the right ...
4
First, check your weep hole as per mike's answer. I'm a bit doubtful, though, because if it's leaking enough to be wet in the morning I would expect a puddle of some kind. I would also expect a squeal on hot starts.
Squealing on a cold start on older cars is usually an accessory belt that has lost tension, especially if it momentarily comes back when the ...
4
The short answer is that you should always be guided by the maintenance schedule by the calendar set forth in your owner's manual. It will have a detailed calendar based on your usage profile and setting forth major items based on miles or dates, depending on what's most appropriate. Using my car as an example, there's a moderately major service required ...
4
Most of the time a ground loop is the cause of this problem. This problem is common especially if your stereos speakers are amplified, and can be fixed my making sure that your stereo unit and/or amplifier have a good ground connection. This can be done by either finding a more direct ground connection to the cars frame, sanding the area around your ground ...
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