tachometer and fuel guage quit working..

My tach and fuel gauge suddenly quit working. My batteries needed replacing as the engine was struggling to turn over. I have since replaced my batteries, but the tach and fuel gauges still don't work. The tach on the flying bridge works fine (no fuel gauge up there) and I took my alternator in and it tested ok. I can't find any disconnected wires and I'm thinking maybe a grounding problem?...I'm wondering what could have caused the cabin tach to go out and not the one on the flying bridge...any suggestions?

for both to go out at the same time...either 12v supply or ground may have disconnected for some reason...but without looking at the wiring behind them...it's all just a guess...

Yup. . . I've had that happen too. If you look at your gauge terminals. . . I'll bet they have daisy chained the grounds together. Find the bad contact and they'll both probably start working.

Thanks psneeld.
Well they both have 12 volts going to them, so I'm thinking a ground problem. It dosen't make much sense to me that one would work and not the other. But then I don't know much about how this boat is wired yet.

Yes I have looked at them and they certianly have daisy chained the grounds together.. actually looks like everything is daisy chained together! .. I guess it'll just be a process of elimination.. Oh well, another sunday spent tracing wires and figuring out the logic behind it all, twisted up like a pretzel!...haha..pretzel logic...a little Steely Dan humor for ya...I must be gettin old...

We're all getting old.

Get one of those long bus bars and every time you disconnect a ground run it to the bar. Give every wire it's own terminal and if you don't have a dry boat, use a touch of dielectric grease on the contact.

If you changed out the batts , you may have not grounded all the wires to the batt.the way they were.

Sadly even builders lay layer on layer of wiring , so on old boats to find a birds nest is common.

Same problem. Under the dash instruments I found a square, multi wire connector. pushing the wires together from both ends of the connector brought stuff back to life for a while.

koliver said:

Same problem. Under the dash instruments I found a square, multi wire connector. pushing the wires together from both ends of the connector brought stuff back to life for a while.

Click to expand...

Love the " for a while"! Yep. Sometimes that is good enough

thanks for the replies. Still looking...I may have some voltage leakage on my main bilge switch..on my start bank, and something else on my house bank seems to be drawing current when it shouldn't..but it's not the rear bilge switch..something apparently from the distribution pannel. Something tells me it has to do with the bilge pumps switches, but I'm not sure. If I had the money I'd throw it at it and make it go away, pain in the #!%

If you have a bird's nest at the battery terminals do your best to get rid of it. Get some H.D. buss bars and make all the connections to the rest of the boat at the busses. Then use one heavy battery wire to each buss bar as required. If you have parallel batteries for a bank then make each positive wire from each battery the same length as each other. Do the same for the negative wire. It does make a difference.

I did that many years ago and am glad I did. I had the potential of the following problem.

I have been helping a friend undo a mess. He has a birds nest at the battery terminals and during the the last battery changeout one lead got misconnected and he had 24V on part of his system. Part of the problem is nothing was labelled or colour coded so when one lead got out of place guess what, it was connected to the wrong polarity. Ruined his alternator controller,, seems to have damaged the battery charger, the inverter didn;'t like and it lost some smoke. Of course he is electrically challenged, hired stuff out, so wasn't really aware but regardless it can happen and one of the reasons is the 20 odd connections all over the place.
With the buss bars, once done, when the battery needs replacement there is only a single pos and neg wire to be undone. No other leads need be touched.
Of course colour code andlabell also but at the least the busses.