Digital Multi Meter-blown fuse question and need help.

[Loose Ctrl]

I have a digital multi meter I use for auto diagnostics. Today, I blew the fuse while doing a parasitic draw test. My meter explicitly says on the DC side "MAX 10 AMP FUSED". While performing the parasitic draw test, I hit one fuse that was pulling 1.89 amps, and the fuse blew. It took me a few minutes to realize what happened. When I pulled the fuse out of the multi meter, the designation on the mini glass fuse was "F02AL250V". It's a 2 amp fuse. I looked it up to make sure. Why would my multi meter have a 2 amp fast blow fuse when it clearly states it has a 10 amp fuse? I want to make sure I am not going to screw up my meter by installing an actual fast blow 10 amp fuse.

 

[Olafur]

Some meters have dual amp circuits, one for low current measurement - perhaps up to few hundred milliamps. And another that goes to 10A and thus - two fuses.

What kind of meter are you using?

 

[DHCrocks]

hmmm.. maybe the fuze was the wrong type? I have not seen a glass fuse in a multimeter, it usually has the solid ceramic type.

 

[dogdog]

I once just plug the multimeter directly to the +\- terminal forgot that I was on AMP setting instead of volt/ohm plugin to the wrong hole too.

DUnno what you got, but mine Extech 470 or aka Craftsman professional one from 10+ years ago is like that. It does have dual fuse and it is a PITA to change...

read the fine manual from your meter manufacture if that is a concern on type of fuse used.

 

[richfinn]

It sounds like the meter has the wrong fuse installed unless it has dual amp Jack's.

My meter has a 400mA and a 10A jack and two separate positions on the dial

I'm more confused about how your doing the parasitic drain test to be honest??

Did you have the meter in series between the battery terminal and post when it blew or were you shorting fuse terminals or something??

I just use the millivolt scale on the meter to measure volt drop across the fuses to find the offending circuit usually after letting the car go to sleep for half an hour or so

 

[Loose Ctrl]

It's a single fuse. Single amp jack. I have it apart. It's a no name unit, but has served me well until yesterday. I got it as a birthday gift several years ago. A Fluke knock off. Most everything I use it for is less than one amp at 12 volts DC. I had it set up properly to do a parasitic draw test. Usually I am looking at anything drawing 0.05 amp to 1 amp. Yesterday was the first time I broke 1 amp doing this test. I had it connected between the ground wire and the ground terminal on the battery. I pulled the fuse that was drawing 1.89 amps, and it popped the fuse. I feel that my multi meter should have not had any issues with it. Sorry for the abbreviated response. It's a holiday weekend and we're out the door for the day.

 

[billford]

A little off topic but, on all my multimeter test leads, I solder in a inline fuse holder that is a little under the multimeters internal fuse rating. If any fuse is going to blow, its my easily replaceable inline fuse not the internal multimeter fuse.

 

[Wrench97]

I have several meters with 2 fuses a small one like you pulled on the volt/ohm ports and 10 amp on the amp port.
I will second the suggestion on adding a inline fuse to the leads for amp draw tests, I use a 8 amp fuse.

 

[Wrench97]

It sounds like the meter has the wrong fuse installed unless it has dual amp Jack's.

My meter has a 400mA and a 10A jack and two separate positions on the dial

I'm more confused about how your doing the parasitic drain test to be honest??

Did you have the meter in series between the battery terminal and post when it blew or were you shorting fuse terminals or something??

I just use the millivolt scale on the meter to measure volt drop across the fuses to find the offending circuit usually after letting the car go to sleep for half an hour or so

Voltage drop across the fuses works well when you can get to all of them, the j case fuses can be a pain to jet the top caps off as can the new mini fuses with no test slots. And then there is finding all the fuses for the owner added accessories........................................

 

[richfinn]

Voltage drop across the fuses works well when you can get to all of them, the j case fuses can be a pain to jet the top caps off as can the new mini fuses with no test slots. And then there is finding all the fuses for the owner added accessories........................................

I've got a j-case fuse loop and a cool set of fuse adaptors (I think there are six different variations in the kit I've got/made in Canada). I try never to pull fuses doing a parasitic as it wakes stuff up on the network sometimes.

Those fuses without test ports are the work of the devil, I would love to bump into the bast*rd that thought that was a good idea (in Europe the French love to use them)

 

[Loose Ctrl]

My fuse location on my Cavalier is on the side of the dash where the door opens. I was running my ground lead to the cars ground wire and the positive to the battery ground. I had the meter set on the 10a 20v DC setting. I was getting 1.89 amps after the car sat all night and I put a fully charged battery in it. I pulled fuses on the dash side fuse block until the draw went away. When I pulled the fuse that was pulling 1.89 amps, the multi meter fuse blew. I don't know why this happened. Once I get the new, possibly correct, fuse I'll try again. I'm considering buying an Amp Hound or Cen-Tech's version from Harbor Freight. Good idea on adding the fuse. I'll do that when I try to do any more parasitic drain tests. I have the necessary parts in my electrical stores.

Amp Hound on Amazon

https://www.amazon.com/dp/B01N0LR29B/?tag=atomicindus08-20

 

[Wrench97]

My fuse location on my Cavalier is on the side of the dash where the door opens. I was running my ground lead to the cars ground wire and the positive to the battery ground. I had the meter set on the 10a 20v DC setting. I was getting 1.89 amps after the car sat all night and I put a fully charged battery in it. I pulled fuses on the dash side fuse block until the draw went away. When I pulled the fuse that was pulling 1.89 amps, the multi meter fuse blew. I don't know why this happened. Once I get the new, possibly correct, fuse I'll try again. I'm considering buying an Amp Hound or Cen-Tech's version from Harbor Freight. Good idea on adding the fuse. I'll do that when I try to do any more parasitic drain tests. I have the necessary parts in my electrical stores.

Amp Hound on Amazon

https://www.amazon.com/dp/B01N0LR29B/?tag=atomicindus08-20

The problem with pulling fuses is, if it is connected to a module you may wake up the module and it can take up to 45 minutes for it to go back to "sleep".

 

[richfinn]

My fuse location on my Cavalier is on the side of the dash where the door opens. I was running my ground lead to the cars ground wire and the positive to the battery ground. I had the meter set on the 10a 20v DC setting. I was getting 1.89 amps after the car sat all night and I put a fully charged battery in it. I pulled fuses on the dash side fuse block until the draw went away. When I pulled the fuse that was pulling 1.89 amps, the multi meter fuse blew. I don't know why this happened. Once I get the new, possibly correct, fuse I'll try again. I'm considering buying an Amp Hound or Cen-Tech's version from Harbor Freight. Good idea on adding the fuse. I'll do that when I try to do any more parasitic drain tests. I have the necessary parts in my electrical stores.

Amp Hound on Amazon

https://www.amazon.com/dp/B01N0LR29B/?tag=atomicindus08-20

Don't waste any money on an amp-hound I'll post up a copy of the chart, you can just use a regular multimeter and it does exactly the same thing, all the amp hound really does is convert mV to Amps, the chart is extremely easy to use

 

[billford]

You can also measure amperage with a voltmeter and a shunt connected to the battery for higher current draws of 1 amp.

I have all the parts, going to try this in a few weeks to see if its usefull:

Another setup:

 

[Rabid Badger]

It's a single fuse. Single amp jack. I have it apart. It's a no name unit, but has served me well until yesterday. I got it as a birthday gift several years ago. A Fluke knock off. Most everything I use it for is less than one amp at 12 volts DC. I had it set up properly to do a parasitic draw test. Usually I am looking at anything drawing 0.05 amp to 1 amp. Yesterday was the first time I broke 1 amp doing this test. I had it connected between the ground wire and the ground terminal on the battery. I pulled the fuse that was drawing 1.89 amps, and it popped the fuse. I feel that my multi meter should have not had any issues with it. Sorry for the abbreviated response. It's a holiday weekend and we're out the door for the day.

Never trust a no-name meter to meet its claimed specs.

A Uni-T UT-210E is useful for checking current draw without breaking the circuit.

 

[tester19]

Yes get a clamp on DC ammeter and your life will be much simpler! Quick and fast as posted above. I hate trying to place the meter in the circuit. What a pain!
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[kbeefy]

This takes ATC fuses and they are super easy to change. I use one all the time.

Not sure how your draw could have increased when you pulled the fuse, but just because you were reading 1.89A before it blew doesn't mean it didn't get a lot higher draw to blow the fuse.

 

[Loose Ctrl]

My car is a base 98 Cavalier. It only has one module that controls the interior lights that auto dim and shut off about 30 seconds after the car is shut down and all the doors are closed.

 

[Loose Ctrl]

Don't waste any money on an amp-hound I'll post up a copy of the chart, you can just use a regular multimeter and it does exactly the same thing, all the amp hound really does is convert mV to Amps, the chart is extremely easy to use

I know the chart you're talking about. I have a small pocket size laminated version somewhere. I got back in the day when I was an ASE certified auto tech.

 

[Loose Ctrl]

Yes get a clamp on DC ammeter and your life will be much simpler! Quick and fast as posted above. I hate trying to place the meter in the circuit. What a pain!
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I agree. I've owned a Fluke meter with the optional clamp on ammeter. It cost me $800, IIRC, back in 1995 when I got serious about my job as an auto tech. When my boss retired, after her wife came down with cancer, I had no job prospects. A guy came in willing to buy me out, so I could payoff the tool guys I owed money too, I made the deal.

 

[Loose Ctrl]

This takes ATC fuses and they are super easy to change. I use one all the time.

Not sure how your draw could have increased when you pulled the fuse, but just because you were reading 1.89A before it blew doesn't mean it didn't get a lot higher draw to blow the fuse.

That is similar to an amp hound, except it measures across the top of the fuse on the contacts and can do all sizes of blade style fuses from minis to the huge maxi fuses.

 

[Loose Ctrl]

We have a great electronics shop down in the city, if they're still in business. I'm going to take my meter into them and have them check it out. I had nearly forgotten about them since I don't do electronic or auto work any more.

 

[kbeefy]

That is similar to an amp hound, except it measures across the top of the fuse on the contacts and can do all sizes of blade style fuses from minis to the huge maxi fuses.

An amp hound measures voltage drop. The fuse buddy goes inline just like your multimeter and measures current directly.
There are different models with different terminals to fit different size fuses, I usually just use it with aligator clips. I do have some fuse adapters if I want to measure a specific circuit, though I usually use a scope for that because digital will miss the in-rush current spike.

 

[Loose Ctrl]

Mystery solved! My meter did have the wrong fuse. The proper fuse was a 10 amp. The fuse type was supposed to be F10AL250V. These are small weird glass fuses. They are 3/16 inche by 3/4 inch or 5mm x 20mm. They're not like the tiny ones in Christmas lights or small appliance type. They're also a lot smaller than the automotive type us older fellows have dealt with in years gone by. I found them on Amazon.

https://www.amazon.com/gp/product/B095CWYG5Z/?tag=atomicindus08-20

This picture is for reference. I didn't buy the fuse listed in the chart. I bought the proper 250v 10 amp fast blow fuse for my meter.

 

[ycgoat]

I use an Ideal clamp on meter that measures DC amps, I think they tun about $125

 

[Loose Ctrl]

I use an Ideal clamp on meter that measures DC amps, I think they tun about $125

That's cool. I had a Fluke back in my auto tech days. Now, I'm just trying to get mine repaired, so I can get back on my project.