Where to test voltage?

[haydenfox]

Im troubleshooting my navigation lights, again. Neither work and the stern light is a plug-in type. Where exactly would I test using a voltage meter to see if they are getting juice? Thanks

 

[Silvertip]

Re: Where to test voltage?

You start at one end of the system and follow the voltage until you lose it. So start at the input to the NAV/ANC light switch. If there is voltage there, you move to the output (load) side of the switch. If no voltage, the switch is bad. If there is voltage move to the hot pin at the light. If there is voltage there, check for a bad ground. Check resistance to ground -- not voltage. A good ground will show continuity. An open will show infinite resistance. You did check the bulbs? If there is no voltage at the lights but there is at the switch, you have a wiring issue.

 

[haydenfox]

Re: Where to test voltage?

You start at one end of the system and follow the voltage until you lose it. So start at the input to the NAV/ANC light switch. If there is voltage there, you move to the output (load) side of the switch. If no voltage, the switch is bad. If there is voltage move to the hot pin at the light. If there is voltage there, check for a bad ground. Check resistance to ground -- not voltage. A good ground will show continuity. An open will show infinite resistance. You did check the bulbs? If there is no voltage at the lights but there is at the switch, you have a wiring issue.

Ok, but where exactly am I touching in each spot to get a reading? Am I going into the wire? And your saying I should have my multi-meter set to resistance? Most of what I've tried to read in the way of info has suggested a test light, so I just assumed. What type of wiring issue?

Forgive my ignorance, Im spankin' new at this! Thanks

 

[Don S]

Re: Where to test voltage?

First thing you need to do is read the instructions that came with your meter. There are some many different types of meters it's impossible to explain how to use your meter or how to even set it.

Here is a thread from the sticky at the top of this forum that may help. http://forums.iboats.com/electrical...rs/no-power-helm-how-test-voltage-583456.html

 

[haydenfox]

Re: Where to test voltage?

First thing you need to do is read the instructions that came with your meter. There are some many different types of meters it's impossible to explain how to use your meter or how to even set it.

Here is a thread from the sticky at the top of this forum that may help. http://forums.iboats.com/electrical...rs/no-power-helm-how-test-voltage-583456.html

Thanks. I have read the info in that sticky, which is one of the reasons I was confused when resistance was mentioned. I always read the instructions of my meter before using it and I understand the settings. But when to check volts, resistance, amps, etc is another story.

 

[gm280]

Re: Where to test voltage?

Okay let me see if I can help you out here. If you are going to check to see if a wire is connected up from one end to the other with no power on, you use the OHMS setting (that would be the resistance scale). If you are checking a place to see if you are getting voltage you would use the voltage scale. Other than that you have to understand what you are trying to confirm before selecting which scale to set your meter to. Most of the time if there is no power applied you would use the OHMs settings (R X 1, R X 10, R X 100 etc). If you are trying to see if you are getting voltage to a certain place then you use the voltage scales and for boat that would be the DC voltage scales as well. If you read zero OHMs on a point then that is closed or shorted. Could be a switch or checking a fuse to see if it is still good. If you read 12 volts at a point that mean there is voltage getting to that point. Could be a starter solenoid or light bulb contact. Once you start using and understand what a good meter can tell you, it becomes your best tool for troubleshooting most anything. But it does take some time and understanding to be able to use such a great tool... There is no one on here that can make you a technician over night.

 

[Don S]

Re: Where to test voltage?

If you want to troubleshoot or work on your electrical system, you have to understand a little bit about what you are working on.

Here are a couple of books that are great for learning the basics of marine electrical without going overboard on all the details and formulas.

THIS ONE may say sailboats, but it has all the information you need and probably the best for the first timers.

THIS ONE is good too, there is a newer version but I haven't seen it and really can't say if it's better or not.

And then there is This One Not near as fancy or as new (It's 30 years old), but the information is correct for basic electrical systems on boats. Plus, you can download it free from HERE

 

[haydenfox]

Re: Where to test voltage?

Agreed, and I'm more than eager to learn as much as I can. S thanks for the resources and replies! But does that mean ya'll aren't gonna' tell me exactly what I need to do to check my lights? lol

 

[Don S]

Re: Where to test voltage?

Post a picture of the wiring side of your nav light switch/s. Since there are many different switches and ways to wire them it's impossible to tell you where exactly to test.

 

[blackhawk180]

Re: Where to test voltage?

No offense to all our great members and their expertise but when it comes to electrical problems/solutions, I scroll down to see what Don S has to say and take it to the bank. Thanks for all your valuable input, Don. You are appreciated.

 

[Todd4]

Re: Where to test voltage?

Haydenfox,

You say you know nothing, so.......:

You have to understand the way a basic electrical circuit works, first, in order to be able to troubleshoot it - or you'll just confuse yourself more with your test results. Then you need to learn how to use your tools. Think of an electrical system as a closed-loop water hose system (water must continuously pump around in a circle).

Battery = pump
wire = hose
switch = valve
light = water wheel (spins as water flows past)
wire connection = (hose joint that can potentialy clog at the joint connection)

If you have water pumping into one end of a hose (wire reads 12V at battery end) and nothing comming out the other end of that hose (no voltage in wire) you either have a break in the hose (wire broken) or a clog at a joint (wire connection corroded).

Just remember you must have water flowing from the pump all the way around the circuit and returning back to your pump at all times (no watering the grass allowed) in order to keep it moving (no extra water supply reserviour is provided). So, if your return hose breaks near the battery - you immediately run out of water to pump = no water flow (no 12V voltage).

So, if your water pump is running (battery is charged) start working your way around each piece of hose (wire) in the circuit looking for breaks or clogs. Only difference is you cannot see an electrical break in a wire like you can see a water break in a hose. Use your V/A meter.

Also, if your water wheel is stuck (light bulb is burnt out) it won't work - so don't forget to check that. Every single component in your circuit is a potential failure point (every wire switch connection bulb, etc) - systematically check everything (each wire, each connection, each switch, each bulb, ect). Start at one end and work your way around the entire circuit, til there is no more voltage.

If you are out of water (battery disconnected) and want to check if a particular hose (wire) has a leak (break) you can use the OHM setting on your V/A meter as a short cut tool.

OK, so before everyone jumps me - electronics are MUCH more complicated than this (I didn't take into account water pressure, check valves, etc), but my analogy above describes the very most basic concept to get you started on understanding your problem - light won't shine.

Also, the books recommended by Don S are VERY good to learn more from - I have one (somewhere), so don't discount them even if you don't understand everything in the beginning - you'll pick it up in no time.

Good luck.

Todd