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Discussion Starter · #1 ·
Ok, I went and got a little multi meter thingy... at the terminals where the gauge fuse goes, it's reading 11.7 volts, 30.5 amps... what's this mean? That slot calls for a 10 amp fuse! Is something broken somewhere? Something not doing it's job? I'm about to pull it all and re-run everything myself! You know, everything else is great... but there's always gotta be one tiny little thing wrong - nothing major, just enough to continuously irritate the living crap outta me!!

Thanks for your help yet again!

Shayne
 

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30 amps are way to high. That’s more than the wattage of three 100-watt light bulbs.
What size fuse is used in this slot by the way?
I would not increase the value of this fuse to solve the problem under any circumstance.
If this is a short it may be a fire hazard, and if it’s pulling 30 amps that’s **** close to a short someplace. You need to take time and find it. Can someone jump in here this looks like Shayne needs more help then I can provide. What I can say is disco that circuit until you find the problem.

Madeline Michele
Hollywood, FL
 

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I have a feeling that you don't really know how to read the multimeter. Please excuse me if I'm wrong. Most "little" multimeters won't even read 30amps, so it might be 30 milliamps (30mA) or 30 thousandths of an amp.

The other possibility is that you are trying to read volts and amps at the same time??? Is it a meter with a needle with different volts and amps scales? You can't read both volts and amps at the same time. If you have the meter set on Volts, then thats what you are reading. To measure amps, you have to disconnect something and put the meter in series with the circuit.

Dave
 

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Without placing the ammeter in line, or using a clamp-on attachment you don't know how many amps you are drawing. Don't use a bigger fuse. Run a new wire if necessary. A short, and consequential fire is a very real possibility.
 

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Discussion Starter · #6 ·
Maybe I am reading this thing wrong...Mmmkay, lets see here... Ok, the meter I have has three settings for amps. 200m, 20m and 2m. It's the digital kind. If I am reading it wrong, which I'm guessing I must be, what do I do to read it right, and to get a proper reading? I had it set on the 20m setting when I read it through the fuse terminals and it came up 30.5. It didn't come with a little book, I got the meter from a friend of mine.

I appreciate the help

Shayne
 

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Did you remove one end of the fuse from the fuse box to get these readings or is your reading across the fuse? Current, amps(A)/milliamps(mA) are typically made in series with probes, especially through a low resistance device like a fuse.

What type of meter is it? Make and Model number.

RLS30
 

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With no fuse in the slot, you are measuring the current correctly. But I would think you'd get an over range indication on the meter if you were truly measuring 30.5 amps on the 20mA range setting. Check the decimal place on your reading. I have a feeling that you've blown the fuse on your meter if you are on the 20mA setting and you are blowing 20A fuses in your car.

What is the maximum current your meter can measure - 10A? Anything above this value will blow the meter fuse and possibly the meter itself. When you change from measuring voltage to current are you also changing the position of one of the test probe connections on the meter?

RLS30
 

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Method

First off, if it's a multimeter that a friend let you borrow it's probably a cheap one. The standard high current measure for most meters is 10 Amps which is beside the point since you're using the meter wrong. If the circuit is blowing fuses then measuring that current that's blowing fuses must be more than 10-20 amps right? So quantifing a current value that's completely off the scale doesn't help does it? You're time would be better spent pulling the dash and checking for fried wires since you've been poping fuses like Chiklets. But I would guess the actual problem is in one of the meter assemblies, or a pinched wire around the air ducts behind the center controls.

With a FSM in hand it would be easy to narrow down the branch of the Gauge power that has the short. First I would pull the fuse box off and check for damage on the backside. Then I would take a good brake light bulb and solder wires to it and to a already blown fuse. Being careful to not short these wires to ground, plug this into the Gauge fuse. I'm sure it will burn nice and bright, this is bad. Now disconnect various gauges until the light goes dim or off. These would be: Tach, Water/Oil, Volt/Fuel, Brake Warning Lamp (Speedo). If none of these have any effect then you have a short internal to your wiring harness.

As an aside: You can't test for continuity to ground (resistance between the Gauge fuse and ground) because the gauges use bimetalic strip heaters which will always look like a short until they heat up.

ConorP
 

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Discussion Starter · #11 ·
Re: Method

Yep, I'm obviously reading this thing wrong. I do believe the highest it will read is 10 amps. I did put the positive lead in the other hole when (trying) to read the amps. I did the unplugging of the gauges and I checked the fuse box and cleaned it up real good. I guess I'll just have to go wire by wire until I figure out where the short is. I guess I've got to find it eventually... there's only so many wires in there. Thank you all for your input and help.

Shayne
 

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K.I.S.S.

Keep It Simple Stupid

Not trying to be offensive, but this principle applies here.

You can trouble shoot most of the wiring problems with a simple meter. Voltage, Resistance and Continuity will give you the indications to fix most of this. Whether the current is 10 amp or 30 amp in a circuit is irrelevant if that circuit is supposed to be dead / null at that point.

I suggest that you address the fuse you know to be going bad. Look it up on the wiring schematic and trace where it connects to per the schematic. Do a simple continuity check to those known points. If they check out all right, then the next step is to address those points that it definitely shouldn't have contact to. As soon as you find one of these, you have your first indication of where your short lies.

If you don't have the schematic, let me know whether your 260 is Automatic or Manual and I'll scan in the schematic and send it to you via e-mail.

Personally, I like the method Conor stated, pull the dash, and start checking the wiring harness for obvious melted wires. If that's totally unacceptable, then at least look at the obvious places that a wire could become loose / frayed or come in contact with stuff it shouldn't come in contact with.

Forget that multimeter, next someone is going to suggest you get a scope and a magnetic resonator and before long you'll be so deep into extraneous BS that you'll forget what you were originally going to do.

When you're up to your ass in alligators, all trying to bite you in the ass, it's really hard to keep in mind that the original reason for stepping into the water was to pull the plug to drain the swamp!
 

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Discussion Starter · #13 ·
Re: K.I.S.S.

Thanks escanlon, I was trying to keep it simple... then all these other ideas were thrown... gets a bit confusing. Anyway, I decided to go digging for the problem... I still haven't found exactly where the problem lies but I did decide to put a fuse in the slot to see what happened... it's fine. Hasn't blown for about 3 days or so. Sounds strange to me, but I aint complaining!!

Shayne
 

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Re: K.I.S.S.

Great, it is now intermittent!

I'll respectfully disagree with a few points in the previous posts. You could be searching all day for fried wires in a circuit/wires that may handle a 15 or 20 amp impulse all day without visibly melting wires (before the fuse melts). Sometimes analog meters have better applications where digital meters don't. Analog needles bounce at real time, digital meters sample and wait.

Wouldn't it be tickling if you quantified the current and then realized afterwards those fuses you were positively sure were 10A and 20A fuses really are 1.0A and 2.0A fuses? Not likely!

Next time the problem shows up I like ConnorP's idea of limiting the current in the circuit to 2 amps with a brake bulb. You then could walk down to the metrology lab pick up a Hall Effect sensor and put Quantum Mechanics to work for you by "sniffing" out the short to its exact location! Sorry escanlon. ;-)

If it does happen again start "popping" open connectors in the circuit until you verify what it is and isn't. Don't hesitate to ask any other questions. Do all of your gauges work now?

Good luck.

RLS30
 
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