Electrical newb question

[Bennylava]

I thought I would ask because collectively, this board knows everything. I'm at the stage of electrical newbness, where I think I'm getting over the hump. That place where you go from fearing and loathing dealing with wiring and electrical gremlins, to finally gaining some confidence in your diagnostic ability. At least I hope that's what's happening.

Anyway I have this idea in my head that if every wire is properly labeled, diagnosis would always be a lot easier. Maybe not easy, but definitely easier. And as such, anytime I work on one of my vehicle's (frequent) electrical problems, I should label every wire as I learn what it is. So is this idea good, bad, or ugly? Any tips to go from newb to amateur would be appreciated.

 

[LopezBart]

Get the wiring diagrams for your vehicle. I don't know how old a vehicle you're dealing with, but modern stuff is really complex, and one needs the factory diagrams w/ color codes for the wires, pin-outs for the plugs, etc. If you're working on a 1965 Suburban, not so much.

 

[Stuart in MN]

A wiring diagram is good, but labeling the wires sure can't hurt. It can be as simple as a piece of tape with the ID written on it, but if you want to get fancy there are heat shrink labels you can run through a label maker.

 

[theoldwizard1]

Are we talking home wiring or vehicle wiring ?

For vehicle wiring, there are hundreds, possibly over 1000 different wires in a modern vehicle. You should be thankful they are different colors as in some application they are all one color.

In the US, all vehicle manufacturers are required to provide access to (SELL) vehicle wiring diagrams. Page and pages and pages !

 

[Burt Shaver]

Following as I would like to become better at diagnosing electrical issues as well.

 

[mm08822]

X2 on the wiring diagram. They can show wire colors, numbers, pin/socket position, pin/socket location. It's easier to review the diagram BEFORE you start trying to follow all sorts of inaccessible paths for things that don't even belong to your "wiring concern". You can use it to figure out if connections are good/bad, reseat them and back-stab them for voltage all before climbing under the dash with your feet needing to stick through the sunroof.

Certainly a tool for working smart.......before you start.

Computer modules add the next level of complexity........but start with the wiring.

 

[Bennylava]

Computer modules add the next level of complexity........but start with the wiring.

Now those I just send off for testing if I ever have a suspicion. Generally I could diagnose them myself but there's almost as many software versions and hack tools and new chips and updates and... on and on forever.

As for the wiring diagrams, the best ones I've seen were made by some forum member and were color coded for the wires. A lot of them appear to just be black and white. Maybe reading them easily is something else you have to get good at. I have not memorized all the electrical symbols.

 

[Chuckster in NJ]

 

[mm08822]

Now those I just send off for testing if I ever have a suspicion. Generally I could diagnose them myself but there's almost as many software versions and hack tools and new chips and updates and... on and on forever.

As for the wiring diagrams, the best ones I've seen were made by some forum member and were color coded for the wires. A lot of them appear to just be black and white. Maybe reading them easily is something else you have to get good at. I have not memorized all the electrical symbols.

Many wiring diagrams (older ones for certain) will be black and white and use text to denote color and a tracer stripe when present.

Newer vintage can be much easier to follow when color is used.

Ask before you purchase.

 

[bornbadbob]

Diagrams are available online too. Generally for a subscription price though

 

[dave*99]

Anyway I have this idea in my head that if every wire is properly labeled, diagnosis would always be a lot easier. Maybe not easy, but definitely easier. And as such, anytime I work on one of my vehicle's (frequent) electrical problems, I should label every wire as I learn what it is. So is this idea good, bad, or ugly? Any tips to go from newb to amateur would be appreciated.

One thought - if I were looking at purchasing a used vehicle and I saw labeling of wires (non OEM labeling) I'd probably lose interest.

 

[Chuckster in NJ]

One thought - if I were looking at purchasing a used vehicle and I saw labeling of wires (non OEM labeling) I'd probably lose interest.

Lose interest?………. I would run!
Electrical issues and hacked wiring is the worst thing that could happen on a modern car.

I collected pinball machines and "IF" I saw ANY hacked wiring or hokey repairs I would run away. These machines had bundles of wires and a lot of solder connections……. Talk about wiring diagrams and following wire colors!

TIP! Wanna "get into" following wiring diagrams and electrical troubleshooting?……… Buy an old pinball machine. Don’t be afraid because there is a lot info and help on troubleshooting and repairing these machines. The nicest thing about these machines is that you can walk away from them if you get frustrated and then come back a day or two later PLUS they don’t take up too much room.

 

[dave*99]

Lose interest?………. I would run!
Electrical issues and hacked wiring is the worst thing that could happen on a modern car.

I was being kind. I'd run too.

 

[Chuckster in NJ]

A friend of mine HAD a 2023 Nissan Frontier pick up that had a issue with the electric drivers seat moving while parked overnight and the dealer could not figure it out, so after repeated trips to the stealership he decided to sell it because he was so disgusted. This was an obvious electrical issue that plagues these trucks and the dealership will try convince owners that nothing is wrong because they bump into the seat adjustment button while exiting the vehicle.……. Moral of the story is make sure you investigate potential issues on Internet forums PRIOR to purchasing any vehicle.

 

[Bennylava]

Many wiring diagrams (older ones for certain) will be black and white and use text to denote color and a tracer stripe when present.

Newer vintage can be much easier to follow when color is used.

Ask before you purchase.

Yeah if they all looked like this, I wouldn't have any problems. Color coding does seem to be a big help. Those older ones you're talking about are just.. hard on the eyes somehow. Like your brain just doesn't want to focus on the information and find what you're looking for.

 

[75gmck25]

Another important change in many modern vehicles is that they use a Controller Area Network (CAN) bus that is (more or less) similar to a computer network at home. Older vehicles used an individual wire to each device, so you would have one wire each for temp, oil pressure, etc. When they started requiring more sensors and a computer to manage them, the number of wires needed took up too much space and weight, and was too expensive.

CAN bus has an address for each sensor and device, and the computer "talks" to the sensors and devices. For example, the temp sensor sends a message to the computer - "temp reading is 200 degrees", and then the computer sends a message to the gauge - "use the stepper motor to bring the gauge needle up to 200". This means you can no longer troubleshoot by simply following the wire from gauge to sensor, temporarily replacing sensors with a known resistance for testing, etc.

 

[dcg9381]

I should label every wire as I learn what it is. So is this idea good, bad, or ugly? Any tips to go from newb to amateur would be appreciated.

For me it depends. If I have a good FSM, there really isn't a reason for me to in and label wires. They're already documented.

When I do "custom EFI" and build harnesses, I'm very particular about making sure every wire has a different color code (impacts costs and storage) as well as drawing the diagram for what I'm building.. Because I'm 100% sure a year later, I'll be "WTF did I do"....

In data centers, I tag every single wire, port gets a label in the switch software, and if you do it wrong I'm gonna kill you.

 

[LopezBart]

For me it depends. If I have a good FSM, there really isn't a reason for me to in and label wires. They're already documented.

I read this as the "Flying Spaghetti Monster" initially... which somehow seems appropriate .

 

[dscheidt]

Another important change in many modern vehicles is that they use a Controller Area Network (CAN) bus that is (more or less) similar to a computer network at home. Older vehicles used an individual wire to each device, so you would have one wire each for temp, oil pressure, etc. When they started requiring more sensors and a computer to manage them, the number of wires needed took up too much space and weight, and was too expensive.

CAN bus has an address for each sensor and device, and the computer "talks" to the sensors and devices. For example, the temp sensor sends a message to the computer - "temp reading is 200 degrees", and then the computer sends a message to the gauge - "use the stepper motor to bring the gauge needle up to 200". This means you can no longer troubleshoot by simply following the wire from gauge to sensor, temporarily replacing sensors with a known resistance for testing, etc.

CAN creates a bunch of problems— a bad module can kill the whole mbus, so you get stupid **** like a broken backup camera causing a no start, and you need to know a fair bit to troubleshoot stuff, both basic theory of operation, but also the topology of the car.

It also does make a bunch of other things possible. because the endpoints are computer controlled (makes remote start, locking, etc just a software feature). It also usually reduces the number of wires going to banks of switches, which means fewer wires to get damaged going to the driver’s door, or through the steering column.

 

[dcg9381]

CAN creates a bunch of problems— a bad module can kill the whole mbus, so you get stupid **** like a broken backup camera causing a no start, and you need to know a fair bit to troubleshoot stuff, both basic theory of operation, but also the topology of the car.

So this is the thing that's causing all the digital signal drama when I simply try to connect to 12V at the 7-pin for internet...

 

[dscheidt]

So this is the thing that's causing all the digital signal drama when I simply try to connect to 12V at the 7-pin for internet...

The seven pins aren’t on the can bus, but what ever is controlling it probably is, if it is a factory tow package.

 

[dcg9381]

The seven pins aren’t on the can bus, but what ever is controlling it probably is, if it is a factory tow package.

I'm kidding a bit, but something is pumping digital signals in there according to my oscilloscope. Won't make a difference on brake lights, but cameras and other devices don't like it as a DC source. You know, the stuff it wasn't built for...

 

[inphx]

if you have a project, you can use the officemax/staples for blueprint size printing if you have an electronic wire diagram. Makes it easier to mark up debugging notes.

 

[Wrench97]

A 1978 White truck had black wires and white wires, white wires were - black wire carried current and were numbered I don't recall any over 2 digits, #36 went to the low beam headlights, by 2001 White had evolved to Volvos and it was not uncommon to have 4 digit wire numbers some followed by a letter to denote branch circuits.