| Re: [GMCnet] starter wiring [message #229223] |
Sun, 10 November 2013 23:13  |
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hnielsen2
Messages: 1434
Registered: February 2004
Location: Alpine CA
Karma: 0
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Senior Member |
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Mike
Where in the back is the second solenoid located?
I have never seen one on ours. "74 Canyon Lands"
Thank You
Alpine Ca
74 Canyon Lands.
All is well with my Lord
> On Nov 10, 2013, at 17:40, Mike Miller <m000035@gmail.com> wrote:
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> Chris Tyler wrote on Sun, 10 November 2013 12:54
>> ...
>> Back to how I wired the boost switch, there were several SOB coaches that worked that way back in the day, and don't really see a downside to it.
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> I'll explain how the stock '75 and up GM coaches boost system was wired and a little on why. You'll need to figure out how the 3rd battery on yours was added and how it effects your systems.
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> GM noted that the separate generator starting batteries in the early coaches was often dead when owners wanted to start the gen-set. (From lack of generator use.) So they eliminated the third battery by moving the house battery to the rear so it could be used for double duty. As the house battery was charged both when driving and when plugged in, it would be more likely to have some charge when the gen-set needed to be started.
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> Fine so far, but to maintain the boost feature a large cable was needed from the house battery to the boost switch up front.
> This worked but it isn't that good a practice to have a large gauge cable connected directly to the battery without any over current protection. So they added a second solenoid in the back. (If the cable is shorted somewhere between the the operator will know it when he presses the boost switch and the solenoids will loose power. One reason for a momentary boost switch.)
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> Now they needed to get the charging current from the engine alternator to the batteries in the rear. So, why not use the big cable that is already there? A circuit breaker jumping the rear solenoid was all that was needed to provide a path for the charging current going into and the house power coming out of the battery.
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> One last thing is on a GM upfitted coach from 1975 on. There is also a connection lug mounted on the wall behind the converter in the hallway cabinets. This is a common connection from the rear solenoid, the front solenoid and the house fuse panel/converter. The cable from that point forward has been a problem on some coaches.
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> I suspect your PO has connected an additional battery in parallel with one of the two battery banks. While it does work, it is very hard to get balanced for any kind of battery life.
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> --
> Mike Miller -- Hillsboro, OR -- on the Black list
> (#1)'73 26' exPainted D. -- (#2)`78 23' Birchaven Rear Bath -- (#3)`77 23' Birchaven Side Bath
> http://m000035.blogspot.com
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| Re: [GMCnet] starter wiring [message #229229 is a reply to message #229223] |
Sun, 10 November 2013 23:36  |
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mike miller
Messages: 3576
Registered: February 2004
Location: Hillsboro, Oregon
Karma: 0
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Senior Member |
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1975 and up.
There were big changes in 1975. The battery/wiring changes where only one of many changes. Floors, interiors, windows, paint, rear boogies and frame also had changes.
| hnielsen2 wrote on Sun, 10 November 2013 21:13 |
Mike
Where in the back is the second solenoid located?
I have never seen one on ours. "74 Canyon Lands"
> On Nov 10, 2013, at 17:40, Mike Miller <m000035@gmail.com> wrote:
>
> I'll explain how the stock '75 and up GM coaches boost system was wired and a little on why.
|
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: [GMCnet] starter wiring [message #229256 is a reply to message #229223] |
Mon, 11 November 2013 07:33 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Senior Member |
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| hnielsen2 wrote on Mon, 11 November 2013 00:13 |
Mike
Where in the back is the second solenoid located?
I have never seen one on ours. "74 Canyon Lands"
Thank You
|
Howard,
Depending on the build number, you may not have one.
Was your house bank located in front and only an APU (genset) battery located in the rear? Then, you don't have one.
If you do it is back by the circuit breaker in the APU space. I have seen then in several places back there, but never paid attention to the location by build.
Easy to find if you have someone clicking the boost switch while you are hunting. They are kind of loud.
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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