Help on getting an electronic tester

[CarZombie 25]

Got some electrical problems with my 1970 Mustang, but at this time not ready to ask for advice on the problems.  I need advice on what type of tester to get more fully ID the problems.  

 

1.   Any recommendations on what to look for someone who knows nothing about electrical stuff, other than it is 12 volts and is negative ground.  Seriously, I have a weak understanding of what I would need in a test unit and what the various tests show me.

2.  A recommendation of a specific unit?

3.  Some general pointers on how to use a test unit ?

4.  Finally some other sites, threads, or videos that might be helpful.  

 

Thanks in advance.

[69RavenConv 286]

A digital multimeter is the workhorse for electrical work. It's called a multimeter because you can measure voltages, currents and resistances (and usually a few other things) with it. For a beginner, something like this $29 unit would be a fine place to start.

 

http://www.autozone.com/test-scan-and-specialty-tools/multimeter/innova-auto-ranging-digital-multimeter/64472_0_0/

 

[1969_Mach1 333]

If you're curious about brands, Fluke is basically the top of the line for digital meters.  It may be overkill but most people that buy Fluke never need to replace it.  I've had my Fluke 77 digital multi meter since 1985.

[danno 128]

The one 69Raven showed is nice. What you will need is DC volts to 20, Ohms ( no maximum is important) and DC current to probably 10 amps.  The other nice feature the one he showed is the Auto turn off.  Mine does not have it, and every time I replace the battery (because I left it on), I wish it had it.  Another nice feature is a beeper to use when you are checking continuity. 

 

I have a cheap one I leave in my trunk, and a better one for in the shop.

[Rip Rock 13]

I have a fluke dmm and a fluke clamp meter. I basically retired my dmm. The clamp meter does everything I need and use it often.

 

http://www.fluke.com/fluke/caen/electrical-testers/clamp-meters/fluke-337.htm?PID=70328 This is the one I have. Discontinued, however there is better units than mine out there.

 

Clamping a wire is a nice feature. I did this the other day. Had a no start on an ls foxbody swap. Clamped the starter wire to find out the cable was too small for starting. With a dmm, I would never found this problem. I can still check for ohms, ac power and dc power ect.

[SA69mach 39]

As a novice I have managed to fix, or diagnose most of the electrical problems with my first Mustang, (a 70 coupe) and since then my second (a 69 Mach 1), using just a few tools.

The multimeter is the best tool, and as mentioned, get one with automatic shut-off, and audible continuity setting.  They are accurate, robust, and can help in many different ways.

The multimeter is perfect for wiring for lights, horns, indicators, anything that is powered, and has a switch to provide the power.  You can use it to test your battery, and your regulator. 

 

A quick and useful tool is the simple test light, which is like a sharp screwdriver with a ground wire hanging out of the handle.  Cheap, and when you clip the ground wire to a ground, (clean chassis metal, or negative battery terminal)  you can easily test your fuses (both ends), and any wire with 12 volt power. 

 

Many times you will need a way to put power into a test item, like a gauge, or a motor for a wiper, anything you have off the car.  For this you will have choice of a purpose built power supply (usually variable voltage)  or simply a good car battery with some big alligator clips on the terminals and small ones on the working ends.  You need to be careful with these ends.  Contacting them together will cause sparking and may damage your item with spikes and shorts.  Rubber coated or shrouded clips will help.  This will help with testing bulbs, especially the small instrument cluster bulbs and bulb holders, which always seem to be sketchy.  I went through about twenty holders and new bulbs to get solid, working sets in both Mustangs.  The 70 has the printed circuit board to power the instrument lights and gauges, for your information.  You also have the IVR - Instrument Voltage Regulator or also called CVR -Constant Voltage Regulator.  This unit breaks down the 12 volt feed to a 5 volt feed to power the gauges.  Remember that if working on gauges - don't use 12 volts direct.

 

For working on gauges and sending units, the Mustangs have a specific resistance range for both.  Ford use gauges and senders that show "full" at 10 ohms, and "empty" at 78 ohms.  Chevrolet use zero to 90 ohms, for reference.  Your temp, fuel and oil pressure gauges are all pretty much identical inside, and the senders are screwed in to the block, or in the gas tank, and are designed to vary their resistance according to changing temps. levels and pressures.  They can be tricky to understand at first, but once you realize how they work with the gauges, it starts to get easier, to diagnose and isolate the problem.

I made a cheap box with a variable ohms output, and two wires to 'simulate' the ohms output to help with my gauges on both cars.  Worked great and saved me time and frustration.

 

Not knowing what issues you are having, that is my list of helpful tools.  Whatever is wrong, it has probably been had before by someone on here, and you will likely find a solution.  Glad you are getting hands-on....post your questions when ready. 

 

 

 

 

[Brian Conway 264]

I suggest, item # 4 on your list, the first order of business would be a set of SHOP MANUALS.  One booklets deal exclusively with electrical.  Brian

[LiLMike 42]

_{The shop manuals are priceless. o are wiring diagrams. You can pick them up all over the internet. Try ebay first and o from there.}

[69volunteer 84]

I've been getting by with the red harbor freight one. Mostly for volts and resistance. They usually give them away every couple of months and I just pick up a new one. I also inherited some crimp on alligator clips that I fashioned into leads (only regret is not making them longer). These are great for running power from the battery directly to a wiper motor or making sure you have a good ground.