| Weird electrical problem [message #212007] |
Sun, 23 June 2013 20:55  |
lance
Messages: 190
Registered: December 2004
Location: Vancouver, WA
Karma: 0
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I have a 1974 Palm Beach with no lights in the bathroom and the porch light also does not work. Yes, I checked the bulbs and the grounds. The bottom fuse on the fuse panel says 'Floor lighting." That circuit has a short. As soon as I put a new fuse in, it blows. Strange that the floor lighting is actually on a fused circuit two or three fuses above because the floor lighting works. So, fused circuit number eight has a short to ground and all other fuses are hot. The switch by the door for the outdoor light shows no voltage. Everything else is functioning normally. Anyone have an idea? It also had a vacuum but it has been removed. That circuit is also dead, no power. These are red and white wires. They also seem to service the bathroom lights. The porch light is a black wire. Fuse number eight is a black wire. Where is the problem? Anyone?
1974 Palm Beach
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| Re: Weird electrical problem [message #212014 is a reply to message #212007] |
Sun, 23 June 2013 22:18  |
dpottebaum
Messages: 100
Registered: January 2013
Location: Bondurant, Iowa
Karma: 0
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I think that wire runs under the coach and has a tendency to get pinched between the body and the frame. That might not apply to all coaches, but I do know it was a problem for 1978 Royale models. It was a discussion topic in the GMC International Newsletter Summer 1983 (volume 1 issue 4). Good luck!
Dave Pottebaum
Bondurant, Iowa
1978 Royale
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| Re: Weird electrical problem [message #212026 is a reply to message #212007] |
Mon, 24 June 2013 03:49 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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First remove the fuses for the circuits in question and clean up both the fuses and the fuse holders. Scotchbrite works well for this. Reinstall the fuses and read the voltage on the connections to the the holders rather than at the fuses themselves.
If those connections were not oxidized and those connections and fuses were are good, then start with one device and meter from the fuse forward to the device looking for where you are loosing 12 volts. Keep in mind that the problem could be on the ground side rather than the +12 volt side of each device.
Also, sometime fuses will ohm meter good and still open up when a load is placed on them. Replacing the offending fuse(s) with a new one(s) might be in order as a test.
The short on the floor light is a different issue. I would pull each light and look for the problem. It is probably a shorted socket or bulb. Keep in mind that many of those floor lights got wired backwards with the socket and frame wired to +12 volts. It never hurt anything because they were mounted in wood.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: Weird electrical problem [message #212036 is a reply to message #212007] |
Mon, 24 June 2013 08:24 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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| lance wrote on Sun, 23 June 2013 21:55 |
I have a 1974 Palm Beach with no lights in the bathroom and the porch light also does not work. Yes, I checked the bulbs and the grounds. The bottom fuse on the fuse panel says 'Floor lighting." That circuit has a short. As soon as I put a new fuse in, it blows. Strange that the floor lighting is actually on a fused circuit two or three fuses above because the floor lighting works. So, fused circuit number eight has a short to ground and all other fuses are hot. The switch by the door for the outdoor light shows no voltage. Everything else is functioning normally. Anyone have an idea? It also had a vacuum but it has been removed. That circuit is also dead, no power. These are red and white wires. They also seem to service the bathroom lights. The porch light is a black wire. Fuse number eight is a black wire. Where is the problem? Anyone?
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Lance,
You have a trouble shooting nightmare on your hands....
My coach had both the clearance and the floor lights wired backwards. (Wasn't that fun when I changed them to LED!)
Once you have done everything that KenB suggested (and probably had some success) but still have not found the true shorts (shorts blow fuses, opens mean nothing happens at all), then it is time for stage two.....
Go get a line tracer (~20$ at Hazard Fright) set the transmitter at the fuse - one wire on the line that should be powered but blows the fuse and the other to a good ground. Now, follow the annoying signal. At some point it may chance (hope - hope) that could be where that line is shorted to ground.
I have had about 80% success rate with this method.
Good Luck
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: Weird electrical problem [message #212068 is a reply to message #212007] |
Mon, 24 June 2013 14:37 |
midlf
Messages: 2212
Registered: July 2007
Location: SE Wisc. (Palmyra)
Karma: 1
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| lance wrote on Sun, 23 June 2013 20:55 |
I have a 1974 Palm Beach with no lights in the bathroom and the porch light also does not work.
<SNIP
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I would check on a 75 living area wiring diagram to see it it matches what you are finding. I'm never sure what the factory did or when they made changes. Also in the maintenance manual are drawings of the 12 (&120) volt interior wiring that roughly show how the wiring was routed. Again no guarantee but it's a start. I don't have any of these materials at hand to take a better look for the problem. Also all this is only true previous to anything a PO did.
Steve Southworth
1974 Glacier TZE064V100150 (for workin on)
1975 Transmode TZE365V100394 (parts & spares)
Palmyra WI
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