gauges not working

[iceman4hct]

no gauges work unless I unhook power/ground from front accessory panel switches and then hook up a power source to them. I've read a ton of forums saying that either a ground is faulty or if one of the gauges 12+volt supply is broke then none of them work. But why would they work when I back feed power/ground from the front?

 

[sw33ttooth]

Re: gauges not working

i would check connections between the first gauge ground startes with, down to the ground bust maybe your wire poped off so there is no 12v- going to the gauges.

 

[NYBo]

Re: gauges not working

Welcome to iboats!

Your post is somewhat confusing to me. Power for the gauges should be coming from the motor's wiring harness via one of the terminals on the ignition switch.

 

[iceman4hct]

Re: gauges not working

Welcome to iboats!

Your post is somewhat confusing to me. Power for the gauges should be coming from the motor's wiring harness via one of the terminals on the ignition switch.

you are correct, power for gauges does come from motor harness. but this all started when i noticed my fish finder up front wasn't working. I removed the panel to check wiring, and removed the power/ground wires(which the fish finder power is piggy backed into) going to the switches on the panel. I then hooked a seperate battery to those wires and both the finder and the gauges worked. I thought maybe the finder was causing the issue so i disconnected it completely and ran the power back to the panel and the gauges(without the finder piggybacking) and no gauges.

 

[Silvertip]

Re: gauges not working

Go to the stickies at the very top of this page and look at the "Generic Wiring Diagram". It details how the gauges are wired. The +12 volt feed for the instruments comes from the "A" terminal on the ignition switch. The switches on your boat are fed by the boat harness -- not the engine harness so they should have no bearing on the gauges. Just look at the +12 volt and ground connections.

 

[iceman4hct]

Re: gauges not working

Thanks for the info Silvertip. I haven't been back to test anything yet(been working too much). But the question that still keeps coming up is, why/how do the gauges work when there's +-12volt being backfed from the switches on the front panel. This tells me that all connections on the gauges are tight and functional, right? While backfeeding power from the front could that allow the gauges to work by providing enough power through the gauge lighting? This whole thing has been a nightmare to solve and I thank you for your guidance.

 

[NYBo]

Re: gauges not working

The short answer to your question about why the gauges work when the front switch panel is powered is that your gauged aren't wired correctly. Here's the diagram to which Silvertip referred:

 

[iceman4hct]

Re: gauges not working

Thanks NYBo, but I wish that were the case, I really do. The only thing different from last Fall when I put the boat away until now is, I put new batteries in the boat. And last Fall everything worked properly and always had. I don't understand how replacing batteries has caused my gauges to suddenly not work the way they had. One thing I didn't mention before though, when I turn the ignition switch on, the trim needle does move from one side of the gauge to the other and the fuel needle moves a smidge but that's it.
Does this indicate a +12 volt issue or a ground issue?

 

[NYBo]

Re: gauges not working

Start with the negative connection. The gauges likely share a daisy-chained connection that ultimately attaches to the negative busbar under the instrument panel.

 

[iceman4hct]

Re: gauges not working

New development- With main power connected to gauges(via ignition switch), there's 12volts coming out of the switch(purple wires-gauge +12v) but only 2.5v at each gauge when switch is "on". So, in an effort to eliminate the possibilities I unhooked the main power at the crank battery. Then hooked up the front panel +/- to a seperate battery(as I did early when I got the gauges to work properly) and once again the gauges all work as they should with the switch "on" with 12v at each gauge.

 

[Silvertip]

Re: gauges not working

This is not rocket science. If the original wiring is not allowing +12 volts to reach the gauges, you are losing voltage somewhere between the POS terminal of the battery, through the engine harness, out the ignition switch to the gauges. Simple as that. Bad connections, weak battery, or bad ground at the battery or wherever the ground point is for the gauges. Switches should have no bearing on the gauges unless you have beenj poking around and have cause some sort of wiring issue. You know the gauges work when backfed, therefore the problem is the +12 volt feed or a bad ground.

 

[iceman4hct]

Re: gauges not working

Trust me, I understand this is not rocket science but that is why it's so frustrating. Nothing adds up. There can't be an issue between the POS terminal of the battery, through the engine harness out to the ignition because there's 12v coming out of the switch(tested). But it's not reaching the gauges(as mentioned only 2.5v at each). But when backfed they are all getting 12v. All I can figure is the gauge lighting wire that is multi-stacked onto the 12+ post on the ignition switch is what's providing the power to make them work when it's backfed. If I had a bad ground somewhere between the battery and the switch, should I be able to start the motor, because the motor will start as well as the trim.

 

[Silvertip]

Re: gauges not working

But the gauges are separated from the ignition switch by about one foot of wire. Trace it. On many boats you don't even need to get under the console as you can undo the instrument panel and lay it in your lap.

 

[iceman4hct]

Re: gauges not working

Thanks for your patience and guidance. Problem has been solved. Through all the headaches and frustrations it all came down to the accessory harness running back to the batteries. When I installed the new batteries I had to relocate the crank battery and the accessory harness couldn't reach the new location so I had connected them to the deep cycle trolling motor battery. I never in a million years thought they would've had to be on the same battery, and it's still puzzling to me but hey the problem is corrected and now I know. Thanks again!!!