Learn Electrical Troubleshooting!

[MrMoMo]

Hey fellow 40 series folks... I posted this over in the 80 series forum, but didn't want to leave all my 40 friends out of the loop, (and I filmed the first 3 on the back of my 40!) - so for those who don't venture into the 80 series forum, I'll put it here as well...


I see a lot of people posting questions here and on Facebook looking for help on electrical issues. Ive decided to create a mini series starting with the basics - to help people learn HOW to find the problem.

In the beginning, I'm starting with the very basics, and will work through how basic circuits work and how to find the problem. Later I will get into specific circuits (using cruisers as examples) and how to locate and repair issues (permanently or temporarily to get home).

If you feel you have zero electrical knowledge and want to learn, have some knowledge but want more, or even feel pretty comfortable but want to learn some tricks, follow along through the series, and you might be surprised at what you pick up. If you have questions or requests - post them in the video comments section, as others may have the same questions.

I have tried to keep the videos short so you only have a bit to retain each time - my hope is that it can help someone, at some point.

So - if you have 4 minutes and want to gain a better understanding - here are links to Episodes 1, 2, and 3;

The Basics:


Open vs. Short

 

[MrMoMo]

Episode 3:
Common points

 

[Ajimenez]

I have a mess here, I am trying to sort out this electrical wiring done to this truck. I was checking all of the wires and found that the wire coming from the ignition to the ignition coil has continuity with the - terminal of the battery or any other ground. I am no electrician but I think this tells me there is a short somewhere, am I right?
Please help

This all started with the charging system overcharging, based on a friend who says to know what he was doing, apparently not we did the following.
My fj has an aftermarket 4 terminal Napa vr440 regulator and a not oem alternator with B E N F terminals. We connected F from alt to F on VR, E on alt to S in VR, and a wire from the + terminal in the ignition coil to A in the regulator.

It seemed to work, I checked the voltage at battery and reading 13.5v at around 2000 rpm. I took for a spin, I started to notice dash light was very dim, then the headlights stop working, when I got home the truck stopped. I immediately disconnected the battery, the VR was super hot, I took all of the wires out, charged the battery and the fj started as usual...

 

[MrMoMo]

I have a mess here, I am trying to sort out this electrical wiring done to this truck.

Exactly what truck are you working on?

I was checking all of the wires and found that the wire coming from the ignition to the ignition coil has continuity with the - terminal of the battery or any other ground. I am no electrician but I think this tells me there is a short somewhere, am I right?
Please help

Is this being measured with the ignition switch on or off? It's normal that some wires that see 12V with the ignition on, will go to ground with it off. Note that if your truck runs, the coil is getting 12V.

This all started with the charging system overcharging,

- this would suggest an issue with the regulator -

based on a friend who says to know what he was doing, apparently not we did the following.
My fj has an aftermarket 4 terminal Napa vr440 regulator and a not oem alternator with B E N F terminals.

Was this alternator installed prior to this issue coming up, or as a fix to the overcharging issue?

BJ40Green has a great thread that should be able to answer any regulator questions, I suggest you take a look here for a good explanation: Voltage Regulator (ext.) / How it works

It seemed to work, I checked the voltage at battery and reading 13.5v at around 2000 rpm. I took for a spin, I started to notice dash light was very dim, then the headlights stop working, when I got home the truck stopped. I immediately disconnected the battery, the VR was super hot, I took all of the wires out, charged the battery and the fj started as usual...

. Charging the battery externally will allow the truck to start normally even if the charging system is not working properly.

I would suggest going through the thread linked above to see if everything on your VR matches. Your regulator may be having internal issues which is putting too much voltage to the alternator field, causing the alternator to over or under charge.

 

[CenTXFJ60]

Man...what a great thread. This is one of those areas I’ve struggled with self educating myself. Tough to learn electrical via trial and error . Looking forward to the upcoming videos.

 

[CenTXFJ60]

Man...what a great thread. This is one of those areas I’ve struggled with self educating myself. Tough to learn electrical via trial and error . Looking forward to the upcoming videos.

 

[CenTXFJ60]

Not sure why this post duplicated. Sorry about that

 

[bj40green]

OL = Open Loop.

 

[MrMoMo]

OL = Open Loop.

Yeah, it's funny how many variations there are of what O/L gets called. I've never heard open loop but I like that - completely makes sense in a circuit. I used to tell people "it's not over load" and I still don't like that, but I gave up arguing. :cD.

I suppose "open line" comes from
when measuring a wire, like a phone line, or power line - that has a break. (?) The key point is to get people understanding that O/L and 0-ohms are opposite, I find a lot of people confuse that... "I checked that - It's no good, it read zero".

 

[MrMoMo]

HAPPY FRIDAY!

Just uploaded episode 4 - using a test light to find problems. Also a sneak shot of my current progress on the 40!

 

[tlaporte]

HAPPY FRIDAY!

Just uploaded episode 4 - using a test light to find problems. Also a sneak shot of my current progress on the 40!

@MrMoMo This is great, clear, concise stuff. Thanks so much for sharing.

 

[bj40green]

TIP: you can also use your jumper cable(s).

 

[MrMoMo]

TIP: you can also use your jumper cable(s).

Very handy!

 

[MrMoMo]

Ok, let's get into Voltage, and hopefully this video helps explain it without confusing people further!

 

[bulldog77]

This thread is much appreciated!

Thank you Bruce!

 

[Rigger]

This thread is great.

Thanks @MrMoMo

 

[MrMoMo]

Thanks guys - hopefully I don't confuse people more!

 

[JuanJ]

Thanks guys - hopefully I don't confuse people more!

Hello,

Your definitions are simple and straight to the point. Two must-have attributes for a good explanation. You got them right.

Keep up the good work.





Juan

 

[todt]

I've been avoiding electrical and carb rebuilding for years. Just rebuilt my carb last week and feeling pretty good about it so this will be perfect. Thanks a bunch for doing this.

 

[MrMoMo]

Well folks, it's been a long week but I put together a quick episode 6, resistance and current...