Help! Gauges, Gauges, Gauges!

[JeffB240z]

When I purchase my 240 about a year ago, the previous owner gave me a big box of extra parts. Included in the box was 2 clocks, 3 Amp/Fuel, and 3 Temp/Oil. It looks like there are a few from a 72' 240z and some from a 74' 260z. See picture.

I was looking for some assistance on what to do with them. The previous owner didn't think that they were working, but based on his overall lack of knowledge for the car, I think i'd like to test that theory for myself. Can someone give me some insight on how to go about testing these?

Secondly, what does demand look like for selling these? I see some on ebay ranging from $30 to $100, depending on the gauge and condition. If they aren't working, is it worth it to spend the money to fix them, then sell them? I'm not overly concerned with getting top dollar for them, they will likely just go back into the box if they aren't worth the time.

Summary

1. How do I test them?

2. Are any of them worth anything?

3. If they aren't working, is it worth it to have them repaired/refurbished?

Thank you!

[grannyknot]

Well they make nice nic nacs for your table  I'll bet most of them work perfectly except the clocks but the clocks are good for cores. The best way to test them is to install them in your dash with the wiring harness and test them under real conditions.

I don't think there is much of a market for them, I have at least as many as you and some tachs and speedos, I take them to Z swap meets and bring them all home again and I'm only asking $10-15. I think the the clocks are selling for about $90 as cores.

[JeffB240z]

Well that doesn't sound as promising as I would have hoped

Good idea on testing the gauges in the car but to pull my dash apart just to test them, seems like a lot of work!

Any other options for testing gauges? Maybe voltmeter, apply a charge to them, anything like that?

[Captain Obvious]

Clock can be tested just by connecting to 12V and see if it keeps time.

Voltmeter you can just hook directly up to a variable voltage source. Should read volts just like any other voltmeter.

Fuel gauge can be tested using a different resistor values or a potentiometer. Here's a thread with some additional info:
http://www.classiczcars.com/topic/55746-fuel-gauge-accuracy-1975-280z/#comment-499020

As for temp gauge and oil pressure gauges, I haven't tested them, but I assume they operate just like the fuel gauge and should be able to be tested in the same manner. Maybe different sender resistance values, but other than that, I expect it to be the same concept.

I have no experience with the ammeter, but if you have a variable voltage source with an adjustable current limit, you can crank the current limit way down and just start trying pins. If you keep the current low enough, you shouldn't hurt anything. Try configurations until you find one that works?

And it could probably go without saying, but on all these tests, make sure you get the polarity correct.

[charliekwin]

As far as value goes, they aren't worth much. I had a full set of gauges left over from a second dashboard I used to replace mine. The tach and speedo are the two most likely to sell for any money, and I only got about $60-70 for the pair. The clock sold for maybe $20 and I still have the others. So it's definitely not worth the effort to fix or refurb them with the intent to sell.

[Mark Maras]

 Store them away. They'll gain value just like all the other parts we used to think were near worthless. Radios, ashtrays, etc.