Some very interesting threads lately. So far everything has been running great. (knock on wood) But have had a weird eletrical problem pop up.
I'll describe it best I can, not to savy on eletrical stuff though, but can do the basics. Anyway instruments are working but the lights in the cluster and the port tach are not working. And when I pull the switch for the intstuments lights the gauges in the cluster for the starboard oil and temp go wacky. Starboard things only. Tach seems to work when running but is wacky when engine off. The only light that works is Port tach.
I took some multi meter readings and seem to be getting power from ground of the instruments and the block of the starboard engine when instrument light swith is pulled. And when I jumper the grounds of both tachs then the light in the pert tach works. Checked the gound connections and they seem good. So I am stumped.
The only thing I can guess at is there is a short somewhere in the cluster panel. And it has a ribbon harness to each side and foil board type connections in it. So it would seem like a short there would not be likely.
I have not messed with any wiring, so nothing to back track there. Sorry if this is hard to follow but I know just enough electical to know I don't know much. Anybody ever have this happen or have any ideas?
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Hi Bill, this probably won't be much help, but I had something similar happen on our Commander when I was trying to hook up the lights for the new electric tachometers I installed. When I hooked the ground up, the instruments went crazy. I checked between the instrument ground and engine block with a digital volt meter, and found about 6 volts. It should have been zero volts.
Sometimes ground systems get some circulating currents in them that can cause problems. I didn't take the time to trace down the problem because the old ground wire was in a place where I really couldn't reach it. I just dragged in a new ground wire from a spot where I knew I had a good ground, and that fixed the problem.
So, you might try fishing in a new ground that you know is good, and see if that fixes the problem.
Best wishes, Curt....
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1967 fiberglass 38' Chris Craft Commander Sportfisher with twin 427 CID 300 HP engines.
That sounds exactly like what I have. When you say you ran a new ground. Where was that too? The engine block or to the instument panel? I am worried that my problem is in the intrument cluster which is all integrated and has the ribbon wire type harness connetors. Which makes it hard to diagnos.
Bill, using my ohm meter I checked the resistance between the engine blocks and the ground bus in the fuse cabinet -- there was zero resistance, telling me that ground bus in the fuse cabinet is a good grounding point. So I just fished a new ground wire from the ground bus up to my tachs, which was only about 3 feet. I was doing this while at the blues festival, so didn't take the time to run down what was going on with the factory ground.
In any case, about half the time when electrical systems do weird things, there is a grounding problem involved. So that is always a good place to start.
Occasionally when you find voltage on a ground wire, it doesn't adversely affect many pieces of equipment (lights, pumps, etc) because the path where the voltage is leaking in from is high resistance, so no significant current really will be flowing in the ground circuit (your volt meter won't tell you that). But if the ground has voltage on it and you are using it on a delicate instrument like an electronic tach, even a very small amount of current can make the instrument go nuts.
If you wanted to trace down where voltage could be getting onto a ground wire, it may be easy or quite difficult. Normally someplace in the ground wire there will be a high-resistance connection (perhaps from a lose wire, or an oxidized connection). If the ground wire in your instrument circuit has a high resistance connection in it somewhere, voltage from the instrument light circuit can't flow back to the main boat ground, so some of it may go to other devices (like instruments) that are also hooked to that ground.
Wiring colors are funny. In residential and commercial building wiring, green is always ground, and white is always neutral (basically, also grounded back in your main panel). But in automotive wiring (and also RVs and boats) often white or black is the ground -- at least for your auxilliary equipment (lights, etc). But there is a real lack of standards. For example, on our bilge pump, black is ground and brown is hot. On some other devices, black is hot and white is ground. On our fuel pumps, red is hot and black is ground. I have been trying to consistently use green or while wires for ground runs on our boat. But the old owner used a lot of green wire for hot wires. It sure is confusing trying to sort all that mess of wiring out, but we are slowly getting it.
I hear you about ribbon cables -- makes it harder to track down what is happening.
Good luck -- that stuff can be frustrating.
Best wishes, Curt...
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1967 fiberglass 38' Chris Craft Commander Sportfisher with twin 427 CID 300 HP engines.
I think I've got some corrosion here and there in my boat, due to the fact that the wiring has been maintained and added onto by previous owners who probably didn't have a clue about the proper wire or techniques. Reading your note here, Curt, gives me the idea to spend some time in the electrical closet with a meter checking all the grounds, leads, etc. and probably doing some corrective wiring to avoid problems in the future. Good thoughts, thank for sharing them.
It's a 1975 aft cabin. Not sure if the tachs are original or not. They look like they could be.
I have not yet found the cause of the problem to many more important things to do first. When running at night this summer I had a little red lens flash to keep on eye on things when it was really dark.
I would have to look again to see which gauges did what and when. But the gauges would get twitchy or dead head one way or another when the intarument light switch was pulled.
Plus the voltage problem from the block to panel ground. It worked last year so I don’t know what changed, cursory look at connections and wires it looked OK. I still need to try Curts gound idea. But still would like to find the cause of the problem otherwise it eats at me.
Everything seems to work fine as long as that switch is off. Temp gauges read right on and oil pressure gauge right on as compared to oil pressure test gauge.
Like you Mark I figured I would work on it over the winter.
I have decided to pull the boat out this year and do a number of things to it. I plan on starting a thread like Paul did. Except mine will be over several months not 11 days!
Here is a list of things to do more or less in order of import.
Bottom Paint
Buff free board of hull
Rudder shaft packing
Check shaft hubs for divots
Shaft alignment
Check Strut bearings
New manifold / risers / hoses / (valve job?) starboard engine
Review electric service
Stanchion fittings
Exhaust hump hose
Rebuild outside deck benchs
Resurface formica counter tops
Install depth finder
I’ll be here all winter too. I think I have figured out a good way to tarp the boat on the cheap and easy too.
Bill what year is your boat? The reason I ask is that I have the same helm and your tachs look nothing like mine I am wondering if they are the originals? Mine are vintage 1975 and I have problems wiht my dash also but it is one of those things I need to get to. Maybe we can compare notes over the winter and figure out what our problems are. I know I do not get all the idiot lights to turn on when I first turn the keys on as they should to show that they are all working only the port alt light comes on the rest are dark.But my gauges all light up when I turn on the switch for instrument lights. Hey we can collaborate in misery together trying to fix some electrical glitches which im my opinion are the worst to diagnose and correct.
Due to ignition switch related issues that I believe have affected the drivability of the boat, I have actually removed accy functions from my ignition switches and I'm dedicating them to "ignition only" and to engine functions. As for all those lights inside the housing, etc., they're very tough to reach on my 38, I have to sit on the countertop and reach deep into the darkness. It was not easy getting to those ignition switches. After looking inside, I decided to keep it simple, and just go with the basics on the ignition switches, in the name of reilability.
This blade switch, for instance, has no business being in the ignition circuit becuase it's just one more thing along the way that could cause the boat to not run or run well. This one was causing my cabin light to flicker the other night and I discovered it was loose just from use, and I tightened it up accordingly.
By taking accessory functions off my ignition switches I know I might leave a device on that could drain down the battery by doing this, but my routine is to use the main battery switch for this function to assure all systems are off except the bilge pumps.
In addition, in the past I have had some very troublesome engine gremlins that were actually traced back to the ignition switch, and the fact that it had so many other wires on it, some of which someone had added, etc. I also noticed some of the wire was not tinned, as Roy recently mentioned, and he's right........non tinned wire will corrode within it's plastic covering, and it's downright dangerous if you are using it in any kind of a critical circuit like the ignition switch. If you lose power in front of an oncoming barge, even if it's a mile away, you may still not have a chance unless the barge is powering up stream. Looking at Bill Murray out on the Ohio River in the middle of all that traffic too, just shows one more time how important the critical functions on a boat are. To lose an engine or two in some of those situations, especially when there is a strong current, could be quite dangerous.
This cool season, in between refreshments on board of course, I plan to go over the electrical box and at least simplify and consolidate some of the extra wiring that has been added over the years for stereos, lights, depth gauges, whatever. I like soldering my connections becuase I hate those crimp connections and don't think they're corrosion proof.
At such time we get such a thing from any source, we'll scan it in pieces so it is readable and we'll post it here on The Forum so anyone and everyone can have access to it.
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