Multi meter

[Newboy]

I'm trying to re-wire the trailer board which is part of the trailer. It had never work from the day I had it, both light clusters were well corroded.

 

I've since replaced the clusters but still have no luck, I wasn't even sure if power is getting thru!

 

I have now bought a multi meter, the instructions are very clear on what I mustn't do with it, but a little short on how to use it.

 

There are 5 groups of selections;

1) 'Omega': (symbol) Rx10, Rx1k

2) ACV: 500,250,50,10

3) Batt: 1.5v,9v

4) DCA:500uA,10mA,250mA

5) DCV:500,250,50,10,2.5

 

I know 1) is for testing a circuit isn't broken and 3) battery tester. I'm totally lost as to the rest.

 

Can anyone shed somelight to using a multi meter please?

 

Thanks

[duncan]

2. Alternating current (AC) measuring voltage

4. Direct Current (as in 12v electrics on boat and car) measuring Amperes

5. Direct Current measuring Voltage

 

2 is measured between Live and Neutral

4 & 5 measured between Positive and Negative (live and earth)

[Barry]

As Duncan said, but for what your trying to do I would have just gone for a simple circuit tester from you local car spares place. It'll be easier to use as the ground side has a crocodile clip leaving one hand free.

 

What is also slightly baffling is that the trailerboard is part of the trailer? Is your trailer a european/uk spec or an american import? Yank trailers are notoriously bad when it comes to electrics. Dunking them in the water when launching probably doesn't help.

[Newboy]

The trailer board has no structural function on the trailer, it's made from the same galvanised metal as the trailer and it clips onto 2 metal claws at the rear. The trailer board has a socket for the 7 core cable to be pluged in just like the elec point next to the tow bar. So all I do at launch is remove the board but leave the cable on the trailer as it's threaded thru the frame.

 

The reason I want it sorted, is at the moment, I have to hang a plastic trailerboard over the outboard and it isn't very tidy.

 

The trailer is made by Satallite, Italian I believe.

[Barry]

Ah right. I know someoneelse thats got that set up. The prob is more than likely, I'll put money on it, in the plug that goes into the trailer board. Probably coroded like like crazy.

I'd bin that set up and use a cable you can take off the trailer.

[Adam F]

Id ditto Barrys comments Kam - a completely seperate set up is far easier to keep in good condition, the ones that are in-built are notorious for corroding...

 

Adam

[Paul D]

Duncan,

 

I am sure you realise this but just in case Kam doesn't DO NOT connect the multimeter when switched to measure current ( DCA:500uA,10mA,250mA ) between the postive terminal and ground/earth/negative. If you do expect something spectacular to happen

 

To measure current the multimeter will need to be connected inline with the power lead ( ie. One lead of the multimeter connected to the power lead of the equipment which has been disconnected from the switch and the other end to the point where the equipment power lead was disconnected ).

 

To check that you have power at the trailer board switch the multimeter to measure DCV ( 50V range ) and then measure between the two terminals feeding each side of the bulb you expect to light - ie. earth and 12V

[Newboy]

Thanks everyone, will give it a go this weekend, when and if the snow melts.....

[Paul D]

No snow down here Kam.

[Newboy]

We have a bit here yesterday and a little today, but it can't quite decide if it wants to stay or no

 

My kids will live a few inches if the white stuff.

[Barry]

I went to the boat today with the intension of pulling it round to the house for a once over before going out over the weekend. I didn't even get to pull it out. Even with the Rangey with the diff locks on I still couldn't get any traction.

No fishing for me this weekend then!

[Coddy]

I'm trying to re-wire the trailer board which is part of the trailer. It had never work from the day I had it, both light clusters were well corroded.

 

I've since replaced the clusters but still have no luck, I wasn't even sure if power is getting thru!

 

I have now bought a multi meter, the instructions are very clear on what I mustn't do with it, but a little short on how to use it.

 

There are 5 groups of selections;

1) 'Omega': (symbol) Rx10, Rx1k

2) ACV: 500,250,50,10

3) Batt: 1.5v,9v

4) DCA:500uA,10mA,250mA

5) DCV:500,250,50,10,2.5

 

I know 1) is for testing a circuit isn't broken and 3) battery tester. I'm totally lost as to the rest.

 

Can anyone shed somelight to using a multi meter please?

 

Thanks

Hi Kam

 

Sorry to be piccy but some points you should be aware of;

 

 

1 'Omega': (symbol) Rx10, Rx1k is for testing the resistance NOT for checking continuity as you may have components which could give you a false reading. For continuity checking use a simple light and two croc clips or a purpose made circuit tester.

 

2 ACV: 500,250,50,10 is for checking voltage of AC or Alternating Current at various voltages, always use one range higher than the voltage you are testing.

 

3 Batt: 1.5v,9v Not seen this one before but could it be for checking the meter's internal battery?

 

4 DCA:500uA,10mA,250mA As Paul said this is for checking the current from a DC or Direct Current supply. The range on your meter is swmall so be VERY careful if using this function. Your current range is 10 to 20 miliamps. DC current is more dangerous than AC and I have seen more elecrical fires started due to short circuits and burt fingers/hands than I care to recall.

 

5 DCV:500,250,50,10,2.5 This can be used for checking the voltages of batteries or a supply which is DC or Direct Current. i.e. checking your battery voltage, again make sure you select the correct range for the battery or supply you are testing.

 

I expect this is as clear as mud now

 

If you have any problems give me a call.

 

Regards

 

Coddy

[Newboy]

I'm a little confused with the Omega thingy, if I make the 2 probes touch, or any metal objects, i.e., shorting them, the needle moves up. So if it's not testing a circuit, what is it measuring, the resistance of the metal objects?

 

To re-cap;

I want to 'see' that power is coming from the car tow bar, to do this, I stick the black from the meter to the white cable (centre one I believe) on the plug and red thru the remaining 6 cables, each one should gives a reading (provided the lights are switched on) if I use DCV 50, right?

 

Am I still making sense?

[Paul D]

Spot on Kam in both cases.

 

You are indeed measuring the resistance ( and it should be well small if it is a metal object ). Dont try this with power applied to whatever you are measuring though

 

The way to check for power applied ( with lights on / brakes lit etc. ) is exactly as you state.

 

[Newboy]

You mean I can't stick the probes into any old 240v wall sockets? Well that's half the fun down the drain.

 

Just went and had a look at the wiring, I unplugged the righthand side light cluster and conducted the test between the socket and the 7 connecters. Here are the results which show a resistance, i.e., the needles moves up the scale.

 

Blue wire to no 1 and no 2 at socket

White wire to 1,2,3,6 and 7

Red wire to 1,2,3,6 and 7

Plus all coloured wire to their respectives at the socket.

 

1=yellow, 2=blue, 3= white, 4= green, 5= brown, 6= red and 7= black.

 

I am sure there should be no reading between blue wire and no 1(yellow), white wire to 1,2,6 or 7, nor red wire to 1,2,3 or 7.

 

Am I correct at saying somewhere inside the socket the terminals are mostly shorted out?

[duncan]

no

[Guest Guest]

I think your making things hard for yourself which is why I suggested a simple circuit tester.

The white wire should go to ground or negative. The yellow and green wires are for indicators the red for brake lights, black and brown side lights and the blue for fogs.

The most common cause for faults is the earth return on the white wire. Often shows up as sides pulsing when indicator is on,.... that sort of thing

 

If your getting readings between thew various feeds then I'd check the back of the socket for corrosion. Also worth checking the plugs on the lead, especially the one at the car end that often gets the wire pulled!

 

Best to strip back to clean wire and make new connections in the plugs sockets working logically back from the car socket. Not unknown for the car socket to be at fault. Its in spray blast from wheels and gets the occasional dunking when launching!

 

I find it best to have minimal connections in the way of plugs/sockets as each one is a potential problem area. A good dose of anti corrosive spray helps keep things conducting too.

[Barry]

^^^^ sorry that was me!

[Newboy]

The cable and plugs on the trailer are brand new (well 2 months ago).

I'd suspected it's the socket cos it's the only thing I can't take apart and it's the only thing I haven't renew. The socket is riveted to the board and I might drill it out over the w/e.

 

Thank Barry, and everyone who chipped in.