70SHEVELLE
May 20th, 08, 9:52 AM
:confused:Just a quick question I hope someone can shed some light on for me. With a fuse taken out, what should I see when I put a meter across that circuit right at the fuse block? I see a hard short on some positions, a med. short on others and nothing on some. The battery is disco'd. Please help. Thanks, Chad
Finally
May 21st, 08, 10:31 PM
With battery disconnected and fuse out you should see open/infinate resistance across the fuse holder. Only thing I can think of is maybe feeding through alternator diodes depending on which way you have the meter leads connected, not sure if that will even happen. What type of readings are you seeing, how many ohms?
vrooom3440
May 21st, 08, 11:24 PM
This one can really vary depending on what circuit you are working with. The resistance value can be a lot lower than you might think too. For example if you have a 20A fuse... the resistance could be as low as 14v/20A == 0.7 ohms. If you have electric motors on the circuit you should also expect much lower resistance since these loads are mostly inductive (they increase during operation).
Feedback between circuits, where present, can also make this interesting. So you have to look at how/where the circuits are switched and if they are fully independent or not (thinking headlights and parking lights here as an example).
Finally
May 22nd, 08, 1:27 PM
If the battery is disconnected and the fuse is pulled then battery side of the fuse holder should be open, not connected to anything. Unless it's feeding through alternator diodes I don't see how you measure anything but open.