Looking For Variable Resistor(s) For Diagnostics

[Ruger77]

Anyone using variable resistors in their diagnostic work?

I have always used a couple of old fuel sending units that I made up with wires attached to help in diagnosing circuits, such as fuel gauges, etc. Although this works ok, I've always wanted something a little better, and maybe with a little more ohm range. I haven't ever seen one made by a tool company, and Radio Shack's looked too light duty.

The tool guys act like I'm nuts when I ask, so....... is it straitjacket time, or does anyone have any suggestions?

[Tim Martin]

Radio Shack is where we get ours. You can get a whole pack of a hundred or so for a couple dollars. Works great in diagnostics. We use them at times.

[steven kiser]

mmmmmmm, this is one thing that i really never put any thought into. i've alway's used a multi meter to test resistance and a jumper wire to test continuity. years ago i was able to purchase a resistor that was adjustable so i could adapt a fuel guage to work in a 54 ford pick up. i believe i purchased it at a hvac supply warehouse. it was a variable fan speed control switch. you could set it up to activate at a series of temps and as the temp increased the fan speed would. this could also be controlled by turning a screw. hope this helps. i tuner from an old transistor radio would work i think. makes sense, at least to me. what ever that's worth...............

[brianp87]

radio shack

[Tim Martin]

We also use resistors in tuning the diesel engines in some applications to alter the shift points for the transmission. Its interesting how some a that stuff works. Alot a fun can be had in these areas if yer willing to invest some time and understand what is being worked with.

[Ruger77]

I'll try Radio Shack again and I might try a fan switch or something along those lines. I have thought about a rheostat out of an old dryer, but I'm not sure what the resistance would be. I was just thinking out loud I guess.

[fortknoxx]

did you ever try to use a tps?

[ricmorin]

I have this tool...

OTC 3385 tester

3385 tester.jpg (7.95 KiB) Viewed 4876 times

Works great.

[Tim Martin]

Yea, I have one of those also. It really works good in testing gauges. The catch with them is the need for reliable and accurate information regarding the gauge and the ohms they operate by when hot, cold, full, or empty. So far, I have found Mitchell 1 to be just what I needed.

[Ruger77]

Thanks Ric, that is exactly what I had in mind! Also, thanks Tina, I have used a TPS at times, but just wanted a little more control and visibility. The OTC tool is what I had pictured in my mind. Thanks for this forum and the great help you all provide!

[crmeyers]

I've got the same tool as Ric. It does work great and I've used it plenty!

[Jeff @ Able Auto]

I have a 3 pin dash pot I got at Radio Shack. Soldered some leads on it..works great. Like Tim said just gotta know the starting point.

[Tim Martin]

Having done alot of electrical diagnostics in the last 15 years or so, I rely immensly on accurate diagnostic information. Especially this is true when diagnosing vehicle dash gauge functions and PCM circuitry. It is interesting what one can learn and observe while doing off job experimenting. There is where we get some of the ideas we incorporate on the job.

Many thanks to Mitchell 1 for a great, accurate, and reliable product!