Bad Gauges?

dsiekman

Senior Chief Petty Officer
Joined
Jul 7, 2010
Messages
798
Okay, I may have committed a rookie mistake here. I rebuilt my dash over the winter and in doing so removed all of my gauges. I was very careful about labeling everything so it would go back without any issues. Now that it is back together, I have tested power and ground at the back of each gauge, but both temp gauges (twins), one oil pressure gauge, and one voltage gauge are not reading anything. What gives? In the interest of full disclosure, I did have to whack a few of the gauges to get them out after unbolting and cutting the 5200 they were sealed in with. Is it possible that by smacking 10 year old gauges I destroyed them? Is there any way to test the temp and pressure gauges to be sure I am getting signal?
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,758
Re: Bad Gauges?

Any gauge with a "send" signal can be tested by connecting +12 volts and ground and then jumping the "S" terminal to the ground terminal. That should peg the meter to the right. If it doesn't you either don't have +12 volts and ground or the meter is toast. Smacking a gauge is not recommended. Voltmeters do not have an "S" terminal and only require +12 volts and ground to operate because -- well -- its a voltmeter. To test the wire and sender on the oil pressure and temperature lines, disconnect those wires from the "S" terminal on the gauge. use an ohm meter to measure the resistance to ground. Both wires should measure about 240 ohms with the engine off and stone cold. At normal operating temperature the resistance should read about 110 ohms in both cases but that can vary significantly. The key factor is that the readings are different than when measured cold indicates the senders and wire are ok.
 

dsiekman

Senior Chief Petty Officer
Joined
Jul 7, 2010
Messages
798
Re: Bad Gauges?

Thanks, Silvertip. I am leaning towards the gauges being toast. I had 12v at each of the bad gauges. I guess they don't like to play rough...:facepalm:
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,758
Re: Bad Gauges?

You also need ground. Without it they don't work. They also need a send signal. Without it they don't workl. Did you do as I suggested about jumpering the "S" terminal to ground? If not, you may very well be replacing a good gauge with another good gauge that also doesn't work.
 

Art Bernard

Banned
Joined
May 4, 2011
Messages
333
Re: Bad Gauges?

InstrumentPanelWiring.jpg

This might help you. I believe I got on this forum and it helped me with my recent gage replacement. All credit to the artist though I can't remember who it was:)

Art
 

dsiekman

Senior Chief Petty Officer
Joined
Jul 7, 2010
Messages
798
Re: Bad Gauges?

Thanks, guys. I tested today as Silvertip suggested. Nothing. Guess they're shot.
 

burp

Petty Officer 1st Class
Joined
Aug 3, 2002
Messages
363
Re: Bad Gauges?

I think I'd go back over the wiring and recheck everything with a voltmeter/ohm meter. Verify each gauge has a good ground connection as well as power connection at each gauge. To me it would be too much of a coincidence to have 4 gauges to go out because of rough handling when you rewired the helm.
 
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