Parasitic Drain - Pyrometer
 

Hey guys, I've been lurking for awhile and would like to poke and prod your brains finally.

I did some hunting and discovered I have two parasitic loads on separate circuits, one is on the interior lights/dome, which I have not had a chance to dive into yet, but I'm sure with patience I'll be able to find the source. Draw is about 110mA.

But the other is the pyrometer. The previous owner had done the install, and I am unfamiliar with the installation process, but I'm assuming its not normal for them to be causing a draw, or at least not as large of one I'm seeing. It draws roughly 120mA.

My gauge has two fuse taps, one for illumination, and one I'm assuming runs the thermocouple. Removing the lead for the illumination does nothing, so it's gotta be in the circuit for the thermocouple, as when I pull that out the drain goes away.

Any suggestions/thoughts?

I wired mine to an ignition hot source.

AFAIK, the thermocouple of a pyrometer in and of itself consumes no current. In fact, it creates current from heat to drive the meter. I would venture that you have some sort of ground fault that is using the pyrometer wire to complete another circuit.

I assume it's the typical 12v tap to run the gauge not the thermocouple.

The current from a thermocouple is relative to some reference point. Cheap (as built, isspro is one) meters just guess that the reference temp is about room temp, and display the difference expected. They don't even have a power connection to them.

Good ones have an artificial ice point reference (32°) and sensitive comparator/amplifier to drive the meter. That one has a power connection and draws a small amount of current. The power supply wire should be wired to an ignition switched source. Either the ignition or accessories circuit is fine.

hope it helps

What is a non "cheap" pyro? My ISSPro has a black box that takes power and ground that the gauge and thermocouple plug into...

I stand corrected. Mine isn't an ISSPro, just looks like the other gauges in the rack that are.

Yours is "non-cheap".

Anyway, now everybody knows how to tell the difference.