Digital multimeter question

On my car i have a plug which melted now my car wont  turn on.  i jumped the plug and now it turns on.  My question is how do i use the dmm to accurately determine a proper fuse value for this wire (I believe that plug served its purpose in melting like a fuse would) the wire has no fuse. dmm is a ET955 madde by mac tools. im new to this please help

Hi Herald,

Before I could anwser your question, I would like to know what the wire is used for? The plug melted because of excessive heat. The excessive heat could have been caused by improper wire size or the electronics at the end of it or just location of the plug in the engine compartment. Just so you know, a plug and a fuse has two different functions. Give some more info and maybe I could help you diagnose your problem.

The connector could've been melted because there was a bad connection causing resistance=heat....enough heat to melt the connector.

I had this happen in my car once because the main engine ground was bad and the engine was pulling all of it's current through a small 12 gauge wire on the other side. Infact, finding that was what lead me to check the ground connection on the transaxle case. After I fixed that, it started right up and runs fine ever since.

If it is indeed a fuse, just look closely at the casing on the side, it will have a rating engraved into it: 40A 250V or something like that.

Just look at a wire gauge chart and use one that will allow max current through that wire.

kgerry wrote:

---

where exactly is this connector? any idea of it's function?  sounds like you might be describing a fusable link...if it comes right off the battery...if not, run out and buy a fire extinguisher just to keep in the car......

---

Connector is about 6in from battery. controlled ingnition,starter, interior lights, door locks and think everything inside the car. not the headlights. its about a 12ga wire. i do have an electric fan that poped the fuse at the same time im not sure if this caused that. this fan has a relay to make it turn on  .

DYohn] wrote:

---

f you melted a connector you have a problem.  Connectors are NOT designed to "melt like a fuse would."  A fuse is designed to blow to protect the wiring and connectors.  You have a fire waiting to happen.  How much load is running on the wiring that goes through this connector, and how large are the wires going through the connector?

---

if you mean current by by load not sure but it does control the stuff stated in previous post.

flynntech wrote:

---

The connector could've been melted because there was a bad connection causing resistance=heat....enough heat to melt the connector.

I had this happen in my car once because the main engine ground was bad and the engine was pulling all of it's current through a small 12 gauge wire on the other side. Infact, finding that was what lead me to check the ground connection on the transaxle case. After I fixed that, it started right up and runs fine ever since.

If it is indeed a fuse, just look closely at the casing on the side, it will have a rating engraved into it: 40A 250V or something like that.

Just look at a wire gauge chart and use one that will allow max current through that wire.

---

i dont know how to quote multiple authors  so i addressed each indiviualy. what am i lookin for when i check the main  ground? make sure its tight thats one, should i clean it with a brush and put silicone over it ? thanks for the help everyone