Head Temp Options

[hedfurst]

Rebuilding a track-car I haven't used for 10 years, it has 2 VDO head temp gauges and was set up for #s 1 and 3. I'd like to be able to watch all four.
Has anybody ever set any thing up for this before? I'd like a switch to change from 1 & 3 to 2 & 4?

[jd74914]

The less costly and more space saving way is to buy any double-pole, double-throw (DPDT) switch and wire each side of the TC to it's respective pole.

CAVEAT: IF YOU GO THIS WAY YOU NEED THE SWITCH TO BE NEAR THE GAUGE.

The reason is that by using a generic switch (without special Nickel-Chromium amd Nickel-Alumel wires, assuming you're using Type K), you introduce cold junction error which puts a bias on your measurement. As long as the switch and your gauge are at the same temperature you're good to go because the compensation is the same. (IMG:style_emoticons/default/smile.gif)

See the picture for a wiring example. For some reason you need to click on it, it's not displaying all of the test otherwise.