Instrument Panel Issues

[Briankinley2004]

Slowly chipping away at the punch list from the engine survey on my 55 Hatteras '85 Convertible. One of the remaining items is "make necessary repairs to instrument panel". Stbd tach doesn't work at all but the port coincides to what the surveyor had with his equipment. At the sea trial and another run the temp on both engines seemed to work. Now the port pegs to 220 degrees or so after a few minutes and the stb goes to 195 while the engine room mechanical gauges both read 145 at long idle and no evidence of overheating. I ran out today and they both read 180 underway and I thought all was well but apparently not. The port volt meter reads correctly but the starboard may slowly rise to 28 volts or so or not move at all. All the other gauges are sketchy except the mechanical ones in engine room which were spot on with what the surveyor measured during the sea trial. Also none of the instrument panel lights work. I don't want to go far from the dock until I get this corrected. Before I start yanking stuff and replacing it are there any common things to look for that would cause multiple instruments to fail but not all? I was thinking ground issues but also was curious as to how to test the various sending units. I know I can swap the one from port to stb on tach to check but on the stuff that neither works correctly I would like to know ohm readings, etc or proper test methods if anyone can provide. Thanks in advance for any input

 

[SEVEN]

Sounds like it’s time to get a new cluster. The ones in the engine room are usually correct. Check the ground. The bulbs can be purchased from Sams.

 

[Briankinley2004]

Thanks. I was thinking of grounding to start with. I have a bunch of bulbs that were on the boat. I haven't gotten under there but was thinking each gauge had its own bulb which would mean very odd that all were out. Maybe there is a bulb for each side? I will check that and start checking for power at switch to being with. Breaker is on in salon.

 

[bobk]

There may be some hidden wiring connections. I don't know the 55, but the 48MY's have three places with buss connections for wires leading to the bridge. If you have the wiring diagrams for the boat it will make the hunt easier.

Do the engine alarms work? If so, I would be inclined to make some local use of the boat while you correct the problems. Just do periodic engine room checks while under way.

Bobk

 

[Glory]

I would ,also, start with ground. If possible get a ground from the nav circuit, providing they work correctly.

The problem is several gauges ground and power are the the only possibilities.

The ground wires are daisy chained from gauge to gauge as power often is.

Good luck.

 

[SEVEN]

There is one bulb for each gage. When I bout mine all but two were burned out so it possible yours are also out. Good luck.

 

[Briankinley2004]

Well there were several bulbs out but shame on the surveyor and me. There is a dial that dims the lights that I found. It was turned down all the way. I checked the voltage on it as I rotated it and it would increase as I turned to the right. I replaced a couple of the bulbs but some were already good. I don't think the issue with gauges not working is the ground as the lights work and are grounded to the gauge case. Also since about half the gauges work and they are daisy chained Im ruling out ground for now. I checked voltage at the back of the inoperable volt meter and its 36V so that will need replacing. As for the tach and temp gauges Im still not sure if its the gauge or senders. I haven't been able to find a test method for either one. I did find info on checking my floscan gauges. They look awful and don't read. Following their instructions I am getting the proper voltage to gauges so I think they are toast. Going to start searching for replacements

 

[Bob Bradley]

Before I spent a lot of time and effort, I'd make up a wire with a couple alligator clips and hook it up as a redundant ground to a known good grounding point. Hook it to each gauge individually and go through the entire panel. Perhaps the lights will work with a crappy ground, but the instruments require a better quality ground. If they still don't work, I would start at the key switch checking for good + voltage going out to the gauges. Follow the + daisy chain.

 

[SEVEN]

Well there were several bulbs out but shame on the surveyor and me. There is a dial that dims the lights that I found. It was turned down all the way. I checked the voltage on it as I rotated it and it would increase as I turned to the right. I replaced a couple of the bulbs but some were already good. I don't think the issue with gauges not working is the ground as the lights work and are grounded to the gauge case. Also since about half the gauges work and they are daisy chained Im ruling out ground for now. I checked voltage at the back of the inoperable volt meter and its 36V so that will need replacing. As for the tach and temp gauges Im still not sure if its the gauge or senders. I haven't been able to find a test method for either one. I did find info on checking my floscan gauges. They look awful and don't read. Following their instructions I am getting the proper voltage to gauges so I think they are toast. Going to start searching for replacements

Don’t feel bad that’s the way you learn your boat. I have a question for you, after I replaced a number of bulbs two of the gauges came on really bright while the others are dull. They are the same bulbs. Are you finding the same issue with yours?

 

[Briankinley2004]

I did notice some of the bulbs a little dimmer although they appeared ok when I grounded to the case outside the housing. Maybe a little corrosion? I was thinking the same thing on alligator clips today except I was thinking of unhooking bad tach and alligatoring to the working tach to see if it read. That would tell me the verdict. I plan on doing tomorrow if it aint raining or too cold. I will try the ground suggestion with clips as well

 

[Boatsb]

All the gauges have a sender that is a known range. I have a few spare parts i use senders to test gauges and a few gauges i use to test senders.

I know not everyone has spare laying around but between that and a good volt ohm meter i can troubleshoot most gauges.

 

[Briankinley2004]

All the gauges have a sender that is a known range. I have a few spare parts i use senders to test gauges and a few gauges i use to test senders.

I know not everyone has spare laying around but between that and a good volt ohm meter i can troubleshoot most gauges.

Thats really the info I was looking for. What should ohm meter read on senders to verify they are OK. It was too cold to go up in the bridge today and swap stuff over but would have been a good day to check sending units in the engine room. I did change out all the corroded connections on the engines today and will see what that does next trip.

 

[Boatsb]

https://www.google.com/search?q=tel...=chrome-mobile&ie=UTF-8#imgrc=Kc7hLKf03fKz5M:


It's for 12 volt gauges but you should be able to work it out for your system.