| Confusing electrical issues [message #260970] |
Fri, 05 September 2014 09:53  |
lance
Messages: 190
Registered: December 2004
Location: Vancouver, WA
Karma: 0
|
Senior Member |
|
|
When I bought my 74 Palm Beach it had two 12 volt batteries in parallel running both the engine and the house. I decided to put it back the way it is supposed to be so I bought another battery, put the two 6 month old batteries on the driver side and the new battery on the passenger side for the engine. Then I tried to sort out the wiring, thinking it can't be that hard.
Well, it is that hard. The two PO's have done this and that and I don't know what is what. A wiring diagram does not help. Electrical troubleshooting is one thing I am not good at. So, what am I asking here? I don't know. I need someone to come and look at my coach. I don't suppose there is someone in the Portland, Vancouver area that is knowledgable and could help. The one local mobile RV repair guy does not do electrical and they referred me to some guy who does not answer his phone. Is there someone close with a 73 or 74 that I could come and look at? The 75 and newer coaches my be a bit different in this area. I'm not sure. Anyone?
Here's my two issues: With the engine battery charged I can start the engine. While relocating the coach five miles, half way there the alternator light came on for a minute then went out. I think the alternator is going. The second issue is that the house batteries do not charge on shore power. There is some suspicious wiring where the two systems intermingle at the isolator and boost switch solenoid.
This forum is so cool! You guys always come up with a solution and I enjoy when my experience can help someone as well. Thanks in advance.
1974 Palm Beach
|
|
|
|
|
|
| Re: Confusing electrical issues [message #261031 is a reply to message #260970] |
Fri, 05 September 2014 21:30  |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
|
Senior Member |
|
|
You have two separate systems there. Engine and house. the are only interconnected on two places. The boost relay / solenoid and the isolator.
I would troubleshoot one system at a time. I would disconnect the battery or batteries on the house side and then go work on the engine side. If something is still powered in the house with the house batteries disconnected, then you know something is cross connected.
Once you get everything working perfectly on the engine side that should be powered by the engine battery and alternator, then stop working on that side.
Reconnect the house battery(s) and disconnect the engine battery. Now start working on house side things like your converter that will not charge the house batteries. After everything is cleaned up on the house side, you can reconnect the engine batteries and work on getting the isolator and boost relay/solenoid working correctly.
While doing this work I would follow the original GMC wiring diagrams as much as possible. Any deviation from them will make it difficult for us or anyone locally to diagnose your existing or future problems.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
|
|
|
|
| Re: Confusing electrical issues [message #261069 is a reply to message #260970] |
Sat, 06 September 2014 11:54 |
lance
Messages: 190
Registered: December 2004
Location: Vancouver, WA
Karma: 0
|
Senior Member |
|
|
Good advice. Thank you. I'll give it a shot and see how far I get except it's supposed to be 92 degrees today. I might wait a bit.
1974 Palm Beach
|
|
|
|
| Re: Confusing electrical issues [message #261078 is a reply to message #261069] |
Sat, 06 September 2014 14:12 |
 |
Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
|
Senior Member |
|
|
lance wrote on Sat, 06 September 2014 12:54Good advice. Thank you. I'll give it a shot and see how far I get except it's supposed to be 92 degrees today. I might wait a bit.
Lance,
You will often find good advice here. That is the direct result of the years Wrong-decades- of experience that frequent these postings. When either Ken posts, I don't ever read with the interest of checking, but there are often is things to learn. In this case, I want to meld the Kens....
Before you get very far, download the wiring diagrams that are correct for your year and print them and put them on a clip board and make notes all over them. If you don't have a label printer, get one. As soon as you identify a something, label it. You may be working on reverse engineering what the POs have done for a while. Don't for one moment think you will remember that all. Your brain would have to be empty to start with just to have room.
Now, You have the diagram and the label printer. What do you do with the wire that you can't figure out where goes??
You put a number label on it and write that number on the wiring diagram where you found that wire connected. This always works, but the PO wiring cannot be expected to work or even make sense.
Matt's short story time
I still have a milk crate in my barn with just the wiring that I removed at did not reuse from one owners boat. I also keep that crate around to use as an example of bad practices. The two worse of these are: Hidden in-line fuses AND conductors that change description mid-run. (What was red at one end is blue at the other and there is a wire nut in the middle.)
Go for it guy. When you get it done, the work will have been well worth the effort.
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
|
|
|
|
|
|
|
|
|
|
| Re: Confusing electrical issues [message #261159 is a reply to message #261081] |
Sun, 07 September 2014 08:35 |
|
Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
|
Senior Member |
|
|
lance wrote on Sat, 06 September 2014 15:50Great advice Matt. Now just give me the link to download that wiring diagram.
Lance,
Sorry about the late response, we have been out of both power and internet here for two days and I can only work the poor old phone just so hard before it goes out and has to sit to recharge. This is worse than underway, there the charger can keep up with the phone being a hot spot and I usually have 4G on an interstate. I can only get 3G here.
Bookmark this:
http://www.bdub.net/GMCLinks.html
The wiring diagrams are here, you should collect the '73s. '73 & '74 were pretty close on most things.
http://www.bdub.net/wirediagrams/
If you have the chance, but the big ones. These can be blown up but they still are tough to follow sometimes.
Good Luck guy
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
|
|
|
|
GMCforum
Search
Help
Register
Login
Home
