| Wiring problem=time bomb? [message #130796] |
Sat, 18 June 2011 22:06  |
Don Walton
Messages: 50
Registered: September 2007
Karma: 0
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As I was looking under the hood of my coach today I noticed a wire connected to the left terminal on the (if I am right about this) magnetic switching solenoid. It is very brittle and the insulation is cracking off. It is a large wire about the same gauge as the starter cable and it runs off the solenoid across the front of the coach and then disappears into the dash. I have checked the wiring diagram in the manual but I am new to the wiring on these. I really need to replace this wire and I hope I can do it without having to tear half of the interior out. Could anyone offer guidance as to where this wire goes in the dash? I don't want to see the GMC melt down. I can post pictures if needed tomorrow. Thanks!!
Don Walton in NC,
75 Glenbrook,
too many MGs
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| Re: Wiring problem=time bomb? [message #130797 is a reply to message #130796] |
Sat, 18 June 2011 22:21  |
John Sharpe
Messages: 489
Registered: February 2006
Location: Texas
Karma: 1
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| Quote: |
...... I really need to replace this wire .....
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Don, what model and year is your coach? The wiring varies on year and whether it's a transmode or not.
It would be a good idea to just all it to you signature.
John Sharpe
Humble,TX
'78 Eleganza TBI
'89 Spectrum 2000 MPI V-10
'40 Ford Panel Delivery TPI
johnasharpe@gmail.com
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| Re: Wiring problem=time bomb? [message #130800 is a reply to message #130796] |
Sat, 18 June 2011 22:35 |
GMCNUSA
Messages: 283
Registered: August 2006
Location: Indianapolis, IN
Karma: 0
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| Don Walton wrote on Sat, 18 June 2011 23:06 |
As I was looking under the hood of my coach today I noticed a wire connected to the left terminal on the (if I am right about this) magnetic switching solenoid. It is very brittle and the insulation is cracking off. It is a large wire about the same gauge as the starter cable and it runs off the solenoid across the front of the coach and then disappears into the dash. I have checked the wiring diagram in the manual but I am new to the wiring on these. I really need to replace this wire and I hope I can do it without having to tear half of the interior out. Could anyone offer guidance as to where this wire goes in the dash? I don't want to see the GMC melt down. I can post pictures if needed tomorrow. Thanks!!
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If you have the "house battery or batteries" in the rear by the Onan generator that wire is probably the one that boosts the engine batteries with the house batteries. There has been problems with the cable shorting to the coach body. It is very deffently a potential big problem.
Larry Dilk
Indianapolis, IN
76 Eleganza II
Patterson 455,Turbo City TBI,
Just LOVE It!
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| Re: Wiring problem=time bomb? [message #130801 is a reply to message #130799] |
Sat, 18 June 2011 22:39 |
John Sharpe
Messages: 489
Registered: February 2006
Location: Texas
Karma: 1
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| Quote: |
.......I really need to replace this wire and I hope I can do it without having to tear half of the interior out.....
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Don, Look in the generator compartment and see if there is a magnetic relay in the battery compartment with a heavy wire the disappears into the coach. I would then think that's the wire. You could be sure by using a test light with it connected and then disconnected. That wire runs through the superstructure inside the walls of the coach. Replacing would involve removing the interior panels the entire length of the coach. Rerouting the replacement to the exterior might be a viable option. Take care to shield it from possible chaffing and use heat shields where needed.
John Sharpe
Humble,TX
'78 Eleganza TBI
'89 Spectrum 2000 MPI V-10
'40 Ford Panel Delivery TPI
johnasharpe@gmail.com
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| Re: Wiring problem=time bomb? [message #130804 is a reply to message #130800] |
Sun, 19 June 2011 00:06 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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I went along that wire and covered it with split loom tubing anywhere it crossed any corner or possibly sharp object. There is a 50 amp. circuit breaker on it in the rear but that does not help much if the short to ground is less that 50 amps. Also with the engine running the alternator can feed up to it's capacity through that cable to a partial short. If you decide to replace it be sure to disconnect both ends of the old one when you are finished. Unfortunately that cable runs through the coach walls to the rear, so a different external under the coach is probably to only practical way to get there. Split loom tubing is cheap. I would run it in split loom tubing down the driver's side of the coach to keep it away from the exhaust system.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: Wiring problem=time bomb? [message #130805 is a reply to message #130800] |
Sun, 19 June 2011 00:17 |
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mike miller
Messages: 3576
Registered: February 2004
Location: Hillsboro, Oregon
Karma: 0
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| GMCNUSA wrote on Sat, 18 June 2011 20:35 |
| Don Walton wrote on Sat, 18 June 2011 23:06 |
As I was looking under the hood of my coach today I noticed a wire connected to the left terminal on the (if I am right about this) magnetic switching solenoid. It is very brittle and the insulation is cracking off. It is a large wire about the same gauge as the starter cable ...
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If you have the "house battery or batteries" in the rear by the Onan generator that wire is probably the one that boosts the engine batteries with the house batteries. There has been problems with the cable shorting to the coach body. It is very deffently a potential big problem.
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You are correct, but this cable also carries the charging current from the engine alternator to the house batteries. (And if you have a combiner, it carries the charing current from your converter the other way....)
On 1975 and newer GM upfitted coaches (like this Glenbrook) the cable is protected my circuit breakers on each end... but the CB's get by-passed when using the boost switch.
I believe there was a tech bulletin on this cable shorting out. (Behind the couch IIRC.)
Unless you are doing a major remodel, I would replace it by running a new wire outside/underneath. (Coachman ran their cables that way.... just not always in the best routes.... draped over steering components and the like.)
Mike Miller -- Hillsboro, OR -- on the Black list
(#2)`78 23' Birchaven Rear Bath -- (#3)`77 23' Birchaven Side Bath
More Sidekicks than GMC's and a late model Malibu called 'Boo'
http://m000035.blogspot.com
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| Re: Wiring problem=time bomb? [message #130838 is a reply to message #130827] |
Sun, 19 June 2011 08:20 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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If you replace it, make sure you use heavy enough wire. That wire carries the current when boost starting the coach. The GMC wiring diagram shows that as 0 gauge wire. You might want to look for some welding stinger cable.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] Wiring problem=time bomb? [message #130841 is a reply to message #130839] |
Sun, 19 June 2011 08:48 |
Don Walton
Messages: 50
Registered: September 2007
Karma: 0
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I thought that wire had time bomb written all over it. Thanks for the link on the wire. I went out and disconnected the wire on both ends. Wire in the generator compartment looks fine and the wire in front looks terrible. I am wondering if there is a splice because wire in rear is black and front is red. Anybody have a nice color wiring diagram?
Don Walton in NC,
75 Glenbrook,
too many MGs
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| Re: [GMCnet] Wiring problem=time bomb? [message #130846 is a reply to message #130841] |
Sun, 19 June 2011 09:05 |
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mike miller
Messages: 3576
Registered: February 2004
Location: Hillsboro, Oregon
Karma: 0
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| Don Walton wrote on Sun, 19 June 2011 06:48 |
... I am wondering if there is a splice because wire in rear is black and front is red. Anybody have a nice color wiring diagram?
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You might be correct. (I do not have a model that has this cable, so I can not check.) Someone posted a picture of a terminal for 12v back behind the electrical cabinet. The pictures show the easist access was pulling the stove.
Mike Miller -- Hillsboro, OR -- on the Black list
(#2)`78 23' Birchaven Rear Bath -- (#3)`77 23' Birchaven Side Bath
More Sidekicks than GMC's and a late model Malibu called 'Boo'
http://m000035.blogspot.com
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| Re: Wiring problem=time bomb? [message #130847 is a reply to message #130796] |
Sun, 19 June 2011 09:06 |
Craig Lechowicz
Messages: 541
Registered: October 2006
Location: Waterford, MI
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Don,
There is a splice behind the wall of the cabinet with the power converter in it where it switches from black to red. It's a bakelite looking terminal mounted to the wall with the 2 large cables plus a smaller one that runs to the coach fuse panel on it.
Craig Lechowicz
'77 Kingsley, Waterford, MI
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| Re: Wiring problem=time bomb? [message #130855 is a reply to message #130847] |
Sun, 19 June 2011 10:20 |
Don Walton
Messages: 50
Registered: September 2007
Karma: 0
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Ok, the splice behind the inverter opens up a new topic in the saga. I was planning to run a new wire from front to back but if there is a junction which powers the fuse panel and I jump it then I am thinking the fuse panel won't have power. I must have an incomplete diagram or either I have not gone deep enough.
Don Walton in NC,
75 Glenbrook,
too many MGs
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| Re: [GMCnet] Wiring problem=time bomb? [message #130866 is a reply to message #130855] |
Sun, 19 June 2011 12:01 |
Dennis S
Messages: 3046
Registered: November 2005
Karma: 2
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Don,
Since you have received good replies about the wiring -- I feel less quilty about redirecting the thread --
TOO many MG's
Photos and an explanation --- please.
Dennis Sexton
73 GMC
1950 MGTD
75 and 76 MGB's
Germantown, TN
USA
-----Original Message-----
From: Don Walton <dhw@rtmc.net>
To: gmclist@temp.gmcnet.org
Sent: Sun, Jun 19, 2011 10:20 am
Subject: Re: [GMCnet] Wiring problem=time bomb?
Ok, the splice behind the inverter opens up a new topic in the saga. I was
lanning to run a new wire from front to back but if there is a junction which
owers the fuse panel and I jump it then I am thinking the fuse panel won't have
ower. I must have an incomplete diagram or either I have not gone deep enough.
-
on Walton in NC,
75 Glenbrook,
too many MGs
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Dennis S
73 Painted Desert 230
Memphis TN Metro
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| Re: [GMCnet] Wiring problem=time bomb? [message #130872 is a reply to message #130846] |
Sun, 19 June 2011 12:26 |
idrob
Messages: 645
Registered: January 2005
Location: Central Idaho
Karma: 0
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| Mike Miller wrote on Sun, 19 June 2011 07:05 |
| Don Walton wrote on Sun, 19 June 2011 06:48 |
... I am wondering if there is a splice because wire in rear is black and front is red. Anybody have a nice color wiring diagram?
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You might be correct. (I do not have a model that has this cable, so I can not check.) Someone posted a picture of a terminal for 12v back behind the electrical cabinet. The pictures show the easist access was pulling the stove.
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Here are the photos on the hidden junction block I have posted on the photo site:
http://www.gmcmhphotos.com/photos/showgallery.php?cat=3916
That block is the location that the power from the converter/charger and the main house fuse block is supplied, so if you bypass the entire wire, you will not have house power or converter charge power. If your large wire looks good at the generator, it will probably be ok to this junction block. From there to the front it goes through the ribs on the driver's side and out the front under the drivers window somehow. I recall that someone found deteriorated insulation there on a coach but my memory is fuzzy on this. You may be fine just re covering the original in the front, as has been mentioned by others, but check it carefully.
This photo shows the large cable in the wall.
http://www.gmcmhphotos.com/photos/showphoto.php?photo=10307&cat=3909
I am pretty sure it is the top one in the photo. I was adding new wires which is the one protected by the gray pipe, second down. The next photo (or previous one) shows the wall apart and where the wires are.
Hope this helps you some.
Rob Allen
former owner of '76 x-PB
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| Re: [GMCnet] Wiring problem=time bomb? [message #130919 is a reply to message #130866] |
Sun, 19 June 2011 17:45 |
Don Walton
Messages: 50
Registered: September 2007
Karma: 0
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Member |
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So Dennis, I see you have a TD and two RBB's. Another one with the addiction. I have a 74b which is my driver and another 74 that is ending up being a parts car. My 73B is on a rotisserie waiting for me to do something with it. I have two GTs that I swear I am going to put a V6 into one of them. Not to mention my 62 rust sculpture A and the junker in the field that used to be a 73 B but is now looking like scrap metal with a good steering rack. Oh yeah, the 64 Austin Mini hot rod. How did I get so mny of these things? Now I am about to tear into my GMC to replace this hidden wire. Now if I just had a whole bunch of time and ....oh yeah, money! I can try to put up some pictures if I can figure out how.
Thanks for the shots of the hidden connector.
Don Walton in NC,
75 Glenbrook,
too many MGs
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| Re: [GMCnet] Wiring problem=time bomb? [message #130920 is a reply to message #130919] |
Sun, 19 June 2011 17:56 |
Dennis S
Messages: 3046
Registered: November 2005
Karma: 2
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Senior Member |
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| Don Walton wrote on Sun, 19 June 2011 17:45 |
So Dennis, I see you have a TD and two RBB's. Another one with the addiction. I have a 74b which is my driver and another 74 that is ending up being a parts car. My 73B is on a rotisserie waiting for me to do something with it. I have two GTs that I swear I am going to put a V6 into one of them. Not to mention my 62 rust sculpture A and the junker in the field that used to be a 73 B but is now looking like scrap metal with a good steering rack. Oh yeah, the 64 Austin Mini hot rod. How did I get so mny of these things? Now I am about to tear into my GMC to replace this hidden wire. Now if I just had a whole bunch of time and ....oh yeah, money! I can try to put up some pictures if I can figure out how.
Thanks for the shots of the hidden connector.
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Don,
Nice gathering of MG's -- the Mini might be a very fun toad.
You have fallen in with a bad lot -- when it comes to auto addiction.
In addition to British cars, we have a Corvette group, a Porsche gang, hot rod section, motorcycle group, VW contingent and more.
If we could ever get one of each GMCers special interest cars in one place we would have a fabulous car show.
Dennis
Dennis S
73 Painted Desert 230
Memphis TN Metro
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| Re: [GMCnet] Wiring problem=time bomb? [message #130922 is a reply to message #130919] |
Sun, 19 June 2011 17:57 |
gmcrv1
Messages: 839
Registered: August 2007
Location: Memphis
Karma: -1
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Don,
If you can find an MGC - it will have the 6 cylinders - ask me how I know...
Tom Eckert N2VWN
73 Glacier
Oakland, TN
On Sun, Jun 19, 2011 at 5:45 PM, Don Walton <dhw@rtmc.net> wrote:
>
>
> So Dennis, I see you have a TD and two RBB's. Another one with the
> addiction. I have a 74b which is my driver and another 74 that is ending up
> being a parts car. My 73B is on a rotisserie waiting for me to do something
> with it. I have two GTs that I swear I am going to put a V6 into one of
> them. Not to mention my 62 rust sculpture A and the junker in the field
> that used to be a 73 B but is now looking like scrap metal with a good
> steering rack. Oh yeah, the 64 Austin Mini hot rod. How did I get so mny
> of these things? Now I am about to tear into my GMC to replace this hidden
> wire. Now if I just had a whole bunch of time and ....oh yeah, money! I
> can try to put up some pictures if I can figure out how.
>
> Thanks for the shots of the hidden connector.
> --
> Don Walton in NC,
>
> 75 Glenbrook,
>
> too many MGs
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
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