Help measuring resistance of fuse with this multimeter

[john2k]

I have a rather old multimeter. I've attached a photo. I am diagnosing an issue with my car. The user guide says to remove the fuse and measure resistance between the terminals and it asks:

Is the resistance vale 1 Ω ± 1 Ω?

Can anyone kindly guide me through how I can use my multimeter to answer that question? I'm not sure why both values are 1 ?

 

[kellys_eye]

It asks to measure the resistance that is any where between 0Ω and 2Ω. That's 1Ω PLUS (or MINUS) 1 ohm.

On your particular meter you would use the 400cCC range, short the two probes together and see if the display shows '0' - it probably won't but that's not a problem. Whatever your meter shows, you need to test and measure according to the instructions and the reading should lie 1Ω either side of whatever your meter shows when the probes are shorted together.

If your meter shows '5' when the probes are shorted then look for anything between 4 and 6 (most likely the higher number).

Since your meter has a continuity function you will hear a beep as you do this. If you hear a beep when measuring across the fuse then the fuse is ok.

 

[john2k]

by 400cCC do you mean like the one I illustrated in the following pic? and also, do I keep the probes connected as they are currently?

 

[kellys_eye]

Yes, the probes as shown and the meter on that range.

 

[HarryA]

The user guide says to remove the fuse and measure resistance between the terminals and it asks:

I have done a lot of automobile repair and never measured the value of a fuse. I have removed fuses and measured the resistance at the terminals that the fuse resides in on the automobile.

 

[kellys_eye]

I have removed fuses and measured the resistance at the terminals that the fuse resides in on the automobile.

What does that prove?

If the battery is connected you will be putting 12V across your meter (on the continuity range) if the load is shorted (the reason a fuse would blow) and if the battery is disconnected you won't measure anything - fault or not.

You can certainly check for 12V on one side of the fuse holder and for a potential short on the other side but 'across it'?

 

[dave9]

I am suspecting this is worded awkwardly and the test is just across the fuse blades to check whether it is blown instead of the instructions reading "continuity test it". The 400 Ohm setting, with speaker icon next to it which should indicate it's continuity mode, would do that.

However many fuses have an opening in the back that exposes contacts on both ends of the active fused element in the fuse body, so you don't even need to pull them out. If the circuit is supposed to be live you can just put one meter probe on any chassis ground point and the other meter probe on both sides (on either side, one after the other in turn) of the fuse through those openings on top. It should read around 12.6V on both sides.

If only one side reads that, the fuse is blown. If you don't get voltage on either side, the test is inconclusive, then you only know the circuit isn't live, not whether the fuse is good.

This also assumes your meter probes have tips small enough to fit in the fuse openings, and the fuse box is located where it's practical to do this instead of awkward and thus easier to just pull the fuse out.

 

[Bluejets]

Glass or blade fuses do corrode at times but it's usually visibly obvious. Original test might be referring to the fusable link which makes more sense.