Hopefully this will be a simple one for the tech guys to answer.

My car has an additional gauges fitted in the space below the stereo. Two of the gauges are for amps and volts, neither was working and on inspection found neither to be connected except the lights. I assume that to get the volt gauge working all I need is an ignition fed live and an earth (correct me if I’m wrong). I’m not sure where to get the feed for the amp gauge though, can I connect into the existing loom behind the panel or will I need to run new wires.

 

Thanks.

 

Steve

 

New wires I reckon steve - and just to be sure the volt meter reads true I would run a new wire to the +ve terminal as well

 

CheerZ,

 

Andy

Volts are directly proportional to amps...OHMS Law me thinks just connect the same wires as would with Voltmeter the gauge should do the rest.....

 

Regardz

Thanks guys.

 

A voltmeter is a useful thing but doesn't really tell the full story. It does indicate whether a battery is charging or discharging, but not much more. On the upside it's very easy to install.

 

An ammeter is a very useful thing because it tells you how much current is being drawn or supplied by the alternator and therefore indicates the efficiency of the alternator and the battery. However, it has to be wired INLINE as opposed to in parrallel with the battery. This means thick wires as all current flows through it. Personally I wouldn't bother as in computing terms I'd call it an SPoF (Single Point of Failure), and we already have more than enough of those. Having looked into the PTU I can vouch for just how fragile some of those are !

Thanks Andy.

Just connected the volt meter and it shot off the end of the scale and then blew a fuse, now Iknow why it was not connected.New one required I guess.

As for the amp meter, can I break into any thick supply wire? If not where should I connect it?

 

Thanks

 

Steve

Steve - DO NOT wire that ammeter across the battery or you will end up having your bonfire night early

As Andy said you need to insert it INLINE with the positive feed - ie cut the wire and use the meter to rejoin.....

 

CheerZ,

 

Andy

Understood.

So a 12v supply run throught the amp meter and terminating at the volt meter with ground at volt meter.

Last point, can I pick up the supply from any ignition fed positive feed?

 

Thanks again

Steve

OK so I'm crap at explaining myself

 

The ammeter must be installed in the main circuit of the car - basically in the +ve wire to the battery - this will take some work unless you want the meter under the bonnet You will need to chop the big thick +ve wire then extend it to the point where the meter is, and then run a wire back into the engine bay for the feed to the engine.... This cable MUST be AT LEAST the the same thickness as the main +ve wire otherwise you'll have a meltdown.

 

The Volmeter is much easier cos it isn't drawing much current so can use almost any thickness of wire All you need to do for the volt meter it to run one wire to the +ve terminal of the battery and use the car body for the earth.

 

Hope this is better explained

 

CheerZ,

 

Andy

The voltmeter maybe faulty or perhaps the ballast resistor is missing, can't think of any other reason why it should go off the scale (which end did it go off ?)

 

To be honest if you don't really know what you're doing then don't connect up the ammeter. I do know (pretty much) and I wouldn't really want an ammeter on my car for the reasons I stated earlier.

 

If you connect the voltmeter then it should be on a switched output, unless you want it on all the time. I know the drain is bugger all, but it is bad practice. So take the -ve to a good earth (the body earth for the battery would be best) and the +ve to a switched output, say off the ignition circuit.

 

Incidentally, the ECU already has a voltmeter, built in somewhere, as it displays on my Techtom.

Thanks for the replies.

I connected the volt meter to the radio supply(nice and close).The needle shot past the 16v mark befor blowing the radio fuse, my multi-meter showed 11.somthing volts.

As for the Amp meter, not really botherd about it so I think I will go down Halfords and look for somthing less dangerous to fit in the hole.

I would have simply removed the gauge panel but it has an extra boost gauge reading bar and a vacum pipe dissapearing to who knows where, don't want to get into removal of that.

 

Thanks for your help

 

steve.

If it blew the radio fuse I'd guess there is a short somewhere.