Equus Innova 3320 Auto-Ranging Digital Multimeter — Mini-Review

© 2011 Peter Free

 

16 March 2011

 

 

Not good for under dashboard, cramped space automobile use

 

Even at its $26 price, the Innova 3320 proved to be more trouble than it was worth under the following conditions.

 

The problems I ran into

 

Several problems surfaced in using the Innova multimeter under my Chevy pickup’s dashboard.

 

I was trying to bypass a faulty windshield washer switch and needed to locate a convenient power source that was hot only when the ignition switch was positioned at “accessory” or “run”.  I also hoped to confirm that the switch was faulty and that there was no interruption in the washer motor’s wire run.

 

My purpose in buying the multimeter was to avoid having to remove the truck’s steering wheel and much of the dashboard, so as to replace the combination wiper, cruise control, and turn signal switch that it is part of.

 

That laziness meant that I was working in a very confined space, often upside down, and was often able only to get one hand partially on what I was trying to test.

 

The Innova 3320 turned out to be the wrong tool for this job:

 

(1) The Innova’s probes are not sharp enough to easily penetrate the insulation on even 18 gauge wire, so it mangles small wires.

 

In confined places, where only one hand will fit, and when working on tightly compressed (but essentially unspupported) wiring bundles characteristic of automobile electrical routing, it is difficult to stabilize small wires enough to penetrate their insulation.

 

The Innova’s probes also easily slip off the intended wire and stick adjacent ones.

 

For me, under these conditions, the 3320 mangled more wires than it read.

 

(2) When turned on, the meter’s readout is always changing, even when the meter is not hooked to anything.  Consequently, it is difficult to know when one has successfully penetrated wire insulation.

 

The readout takes seemingly forever to stabilize and has a tendency to rise and fall erratically when trying to penetrate insulation.  So it is challenging to know whether a wire is dead, has reduced voltage, or one has completely missed making contact with the wire inside.

 

(3) The probes are too short to reach areas that your hands won’t fit.

 

(4) The unit lacks accessory alligator clips.  It is difficult to maintain contact with automotive ground at the same time that one is trying to pierce or maintain contact with a hot wire.

 

(5) There is no blatantly obvious distinction between volts and millivolts on the digital readout.  Under a car dashboard, one has to peer closely at the display to look for the symbol to change from its customary “mV” (millivolt) to “V” (volt).  Trying to hold the display so that I could actually see it would have required a third hand.

 

(6) The display is not illuminated, making it difficult to see in the darkness under dashboards.

 

(7) Unrelated to practical use — but an indication of less than ideal overall design — the unit’s probe-keepers are too loose to hold the probes for storage.

 

 

A cheap test lamp with a sharp probe worked better

 

A 3M brand 6 to 12-volt system test lamp had a significantly sharper probe, an alligator clip on its ground wire, and the lamp was either on or off, eliminating the auto-ranging multimeter’s confusion about whether the circuit was hot or not.

 

The test lamp was much easier for one-handed use.  And its probe mangled the wires less than the Innova’s comparatively dull probes.

 

 

Conclusion — evaluate your working conditions before you buy the Innova 3320

 

Under the cramped automotive conditions described above, the Innova 3320 bordered on worse than useless.

 

It probably works fine when one can bring two hands, firm support, and good light to bear on the project.  But I would not buy another one.  There are too many elements of poorly thought out design in it.