dome lights not working Where is ground buss located?

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Pipercubfan
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dome lights not working Where is ground buss located?

Postby Pipercubfan » Mon Jul 08, 2019 9:25 pm

Hi all my dome lights don't seem to work. I measured the voltage at the socket and switched the switch to the on position wow 12 volts I turned the switch off 12 volts gone. So I thought the bulb was bad even though the filament looked fine. I connected the bulb to a 12 source and wow the bulb lights . Now what. where is the ground buss. I looked behind the medicine cabinet and don't seem to find a buss for the ground. All the other running lights work fine. Any ideas?
Carrying a flashlight is getting old when you have to put the cockpit cover on in the dark.

Thanks Fred

Pipercubfan
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Re: dome lights not working Where is ground buss located?

Postby Pipercubfan » Mon Jul 08, 2019 9:27 pm

PS Also the horn does not work either . I carry a small air horn but that is not what I want to depend on.

Thanks

jralbert
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Re: dome lights not working Where is ground buss located?

Postby jralbert » Mon Jul 08, 2019 9:42 pm

A non-working horn makes the suggestion I'm about to make a bit off base because it's possible the two things are related. But is it possible the fixture itself is faulty somewhere?
Meanwhile, try measuring the voltage at the horn to see if the same thing occurs.
(by the way, adding some boat info stuff to your ID might assist in getting relevant info from people who have the same model - such as where the ground bus might be located. To that, in my 1988 FBS, it was either in the cabinet behind the helm or overhead, just inside the storage area where the cold water tank was located)
-joel-
former owner 1988 '32 FB Sedan
Chesapeake Bay
twin 318 / 240 hp
Potomac MD

Pipercubfan
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Re: dome lights not working Where is ground buss located?

Postby Pipercubfan » Tue Jul 09, 2019 2:34 pm

WELL THANKS BUT I CAN'T BELIEVE ALL THE FIXTURES ARE BAD ESPECIALLY WHEN I TESTED THE FIXTURE AND READ 12 VOLTS SWITCH ON AND ZERO VOLTS WITH SWITCH OFF .I STILL WOULD LIKE TO KNOW WHERE THE BUSS DC GROUND IS LOCATED. MY BOAT IS A 1973 MARINETTE 28 HARD TOP EXPRESS . ALL THE OTHER LIGHTS WORK .I FOUND THE PANEL BEHIND THE MEDICINE CABINET AND THE WIRE MARKED DOME LIGHT AND LOOSENED THE SCREW A FEW TIMES AND RETIGHTENED IT ,THINKING THE CONTACT MAY HAVE BEEN DIRTY OR CORRODED BUT THAT DID NOT FIX IT I ALSO CHECKED THE FUSE AND IT TESTED FINE ALSO. I MAY PULL THE DASH PANEL OFF AND SEE IF THERE IS SOMETHING IN THAT AREA FOR A GROUND BUSS.ANY OTHER 1973 BOAT OWNERS ON BOARD THAT CAN SHED LIGHT ON THIS ISSUE EXCUSE THE PUN
FRED GLMC

ddependo
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Re: dome lights not working Where is ground buss located?

Postby ddependo » Tue Jul 09, 2019 2:48 pm

My 73 express 32 ft had a cabinet door behind the helm, starboard side. All fuses and buss bar are located there. You could drop the ceiling panel and run a new ground wire to another ground connection or to to the buss bar. Run a jumper wire to a ground connection and that will tell you if that is the problem.
Wayne ( sometimes called sparky)
1973 32 express fly bridge
Chattanooga
"Southern Lady"

Pipercubfan
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Re: dome lights not working Where is ground buss located?

Postby Pipercubfan » Tue Jul 09, 2019 4:48 pm

THANKS WAYNE MY PANEL IS BEHIND THE HELM ALSO WITH ACCESS THROUGH THE MEDICINE CABINET IN THE HEAD. THAT PANEL IS THE BACK OF THE HELM STATION ALSO. I JUST DON'T SEE A BUSS BAR FOR ALL THE GROUND WIRES TO ATTACH TOO I JUST SEE THE FUSE PANEL. ARE THERE ANY WIRING DIAGRAMS AVAILABLE THROUGH THIS WEB SITE FOR THIS OLDER BOAT? ALL THE DOME LIGHTS IN THE BOAT DON'T WORK. I THINK IT IS A POOR GROUND SOMEPLACE ,IJUST DON'T KNOW WHERE THAT SOMEPLACE IS LOCATED..I GUESS I WILL BE USING THE OLD FLASH LIGHT FOR A WHILE.
FRED

carl
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Re: dome lights not working Where is ground buss located?

Postby carl » Tue Jul 09, 2019 5:37 pm

BigM
Last edited by carl on Wed Jul 10, 2019 11:29 am, edited 1 time in total.

jralbert
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Re: dome lights not working Where is ground buss located?

Postby jralbert » Tue Jul 09, 2019 9:39 pm

(sorry - you wrote dome lightS (plural) and I read dome light (singular)). Is it possible that there is one ground wire looping from fixture to fixture that's interrupted somewhere?
-joel-
former owner 1988 '32 FB Sedan
Chesapeake Bay
twin 318 / 240 hp
Potomac MD

ddependo
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Re: dome lights not working Where is ground buss located?

Postby ddependo » Wed Jul 10, 2019 7:37 am

Fred, My 73 doesn't have overhead panel. If you take your gauge panel lose and look behind it down and left of the fuses panel you should see the buss bar. Mine has a buss bar close to the fuse panel. It is hard to see from the other side in your cabinet. It makes sense to have it close tho the fuse panel so less wiring is needed.
Wayne
1973 32 express fly bridge
Chattanooga
"Southern Lady"

railrunner04
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Re: dome lights not working Where is ground buss located?

Postby railrunner04 » Wed Jul 10, 2019 8:47 am

Ok so I hope not to ruffle any feathers but from my experience with the wiring on these boats from the 70's to the 90's they are radically different I wouldn't say the newer m's are better but the wire colors are at least close to a standard practice for marine wiring

So in essence a owner that has a 89 marinette describing his electrical system to a guy with a 71 model it's like two completly different boats. I've done some extensive rewiring on my fathers 71 some of it was gutted completely or modified to work with newer components.

Basically on the 71's theres a main power buss that actually has glass buss fuses in it on the 12 volt positive side those wires are multiple colors with no rhyme or reason to them I believe the cabin interior lights are all yellow if memory serves the grounds are (gasp!) White! On the 71 express all the dc 12 volt ground wires are white they should be in a bundle of sorts and all attach to lugs on a aluminum plate behind the gauge panel on the lower helm one of those lugs could be loose the more likely culprit is the copper in the wire has contracted the green death from moisture because oh yeah the entire system incorporated copper wire so unless the previous owner had lots of spare time and money to replace all that with tin core the chances are a majority of the wire is old school copper hope this helps I know it can be frustrating to try and nail down these things!
Moby Rick
FYC grosse ile mich
32ft F/B express
1971
T/318 Chrysler marine