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Need electrical training I need to check out my 32 for shorts. I have a fancy electrical meter but clueless as to how to work through the system and what to set the meter on.
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Re: Need electrical training Jim, I looked through all your pictures and I want to help, but I never saw any of those fancy shorts. What color were they, and did they have little hearts or polka dots? :confused:
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Re: Need electrical training Jim do you have a parasitic draw, is your battery going dead?, or do you have a light not working? To check for a draw you can use a bulb between one side of your battery terminal, if it glows you have a somewhere you just need to start unhooking things until it goes away, then address the problem. If you have a light that doesn't work, unhook the battery and use the ohm scale to check the wire to ground, work back from there. You don't really need expensive gear, just a test light and I use an analog multitester I bought years ago in the dollar store.
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Re: Need electrical training A Volt/Ohm or multi-meter generally has some instructions on how to set them up. Some have different plug sockets for the test leads depending on what type of check is being performed. Ground lead is usually common. When checking for voltage, you will need to use settings for DC voltage. When checking resistance, you will need settings that are in the range of Ohms that the component is rated for. Resistance checks have to be performed with the circuit to be tested isolated from power supplies to protect the meter. Circuits have to be under power to check system voltage.
They are handy to see if power is getting through a circuit with voltage checks. Ohms meter checks can isolate an open circuit due to a broken wire or a shorted circuit due to a bare wire touching the frame. They can do more checks but there is more to learn about DC circuits for a person who is just starting to get into the shocking subject of electricity. |
Re: Need electrical training If you are interested in general information on how to use the meter or perform different test, there are a lot of videos online.
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Re: Need electrical training the service bulletins for 1936 have a pretty complete electrical "course" that is flathead oriented
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Re: Need electrical training 2 Attachment(s)
Alan, if they were these electrical shorts I wouldn't be trying to get rid of them..... Oh wait yes I would.....LOL
This is my meter, instructions have long since disappeared. So what am I setting this on? |
Re: Need electrical training 1 Attachment(s)
For starters here is a wire layout diagram, I know it is not a schematic, but it is useful to newcomers to see where the wires are located on the car.
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Re: Need electrical training 1 Attachment(s)
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This is the battery voltage that you will test for consistently across all your connection. Send the shorts and the gal to my home for closer inspection. |
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Re: Need electrical training Once you click the setting to DC then test it by touching one probe to negative battery terminal and the other probe to positive batter terminal..to see that the meter reads 6 volts...I can read 6-6.5 volts or so.
Then leave the meter with this setting as you will only use this ONE setting for your entire troubleshooting for your short. |
Re: Need electrical training jim1932. I doubt that your car has a "short" in its electrical system. If it did have a short then it would more than likely be blowing a fuse or if no fuse in the circuit then it would be cooking and smoking up some wiring. Many people don't understand what the term "short" (for short circuit) really refers to. All our cars have electrical items which have a power supply delivered by the battery. If this power wire connects or rubs through to ground or the chassis/body before its connection to the electrical item it is meant to be powering then that is a short circuit because the circuit has been shortened. This short will cause a large current to flow to ground because of a reduced resistance in the line. That's why we have fuses fitted in the power supply to stop a burn up of the wiring or even a fire. The term "short" is often used incorrectly for just a failure of an electrical item to operate. Your new multi meter can be used for checking voltage , current and resistance in your cars wiring. The best way to find a short is with your eyes and a good flashlight and follow the wiring around until you find the trouble spot. A test light in series in the power supply of a shorted out wire can be helpful also. It will stay "on" until the short to chassis is corrected. Regards, Kevin.
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Re: Need electrical training Jim, keep in mind one of the most common problems on these 80 yr old cars is poor contacts to ground.
Go through your system methodically, and disconnect and clean each and every connection with a bit of sandpaper or steel wool. You may find your problem has gone away. |
Re: Need electrical training Another problem is the condition of "who knows how old" wiring. The old original stuff has a resin insulation with fabric woven covering that is highly prone to deterioration. New harnesses are available from sources such as Rhode Island Wire and others. As Kevin mentioned, this stuff is prone to short to ground where the insulation has flaked off or even short to other circuits due to multiple wires with severe deterioration.
The Omega symbol on your meter will check for continuity by placing a milli voltage through the wire to be checked and see if the meter indicates a near zero or at least a reading similar to just touching the two probes together. This is why the circuit has to be disconnected at each end or isolated to find the open or shorted wire. You can put one probe on a wire and the other on the ground and see it there is a short to ground due to a continuity indication on the meter. You can also put a probe on one wire then put the other on a wire next to it in a bundle and check for continuity or short between two wires in the same bundle. The multi-meter is a very good tool for checking complicated circuits. On simple one wire circuits you can use a test light probe unless it is continually blowing the circuit fuse. From there you either need to visually check the wire or run a continuity test to see if it will pass voltage through the line. Some wires get corrosion inside where you can't see it and that is where the Ohms meter is invaluable. |
Re: Need electrical training If you search on instruction book for your meter make and model, you might just find the booklet on line.
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Re: Need electrical training maybe youtube for a video instruction??.....good luck....Mike
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Re: Need electrical training Quote:
http://www.gardnerbender.com/en/reso...uction-manuals What you set it to - and how you hook it into the circuit - will depend upon what you're trying to test - continuity, voltage, amperage, resistance, etc. |
Re: Need electrical training Hi Everyone, I like to think of the multimeter as a device to confirm a prediction that I make.
For example when I test a 12v Battery, I predict I'll have 12.6V DC or more for a fully charged battery. Then to set the meter, for Volts DC, and a scale number ABOVE what I predict, in this case I'd select 20V DC. Then after the reading is taken I'll know if the prediction is accurate. I turn off the meter between readings to avoid setting the tool up incorrectly for the next test. Another example, if I were trying to verify a fuse is working, I'd predict to have very low resistance on a good fuse. Setting the meter to Ohms, I'd probe the two fuse ends/contacts and compare to the reading. Some meters will use OL to indicate an infinite amount of resistance, or a open circuit. |
Re: Need electrical training Quote:
If the fuse is blown, the meter will show (approximately) WHICHEVER voltage your battery is.......6v OR 12v......which is the voltage DIFFERENTIAL between the two sides of an open (bad) fuse. PLUS, it's safer to check for voltage FIRST, to preclude checking on the OHMS scale with voltage present. Many meters will either release "smoke", or hopefully only blow the meter's internal fuse if using the OHMS setting while voltage is applied. DD |
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