I need a wiring diagram

[wbemis]

2017 Coachman 31BH Class C. With the 30 amp AC unplugged and the main breaker open, I read 12 VDC from the + DC buss to the AC Neutral buss. I energized my portable inverter (case grounded to chassis) and with the ground and hot legs not attached, the neutral is a hot-short when I touch it to the neutral AC buss. Doesn't make sense to me. Any clues where I can get an official wiring diagram? Thanks to all.

[TheWolfPaq82]

As far as a "Official" diagram for the trailer/coach layout...they don't make them. You'll find diagrams for your inverter, converter, but nothing for the rig itself.

[wbemis]

Originally Posted by TheWolfPaq82

As far as a "Official" diagram for the trailer/coach layout...they don't make them. You'll find diagrams for your inverter, converter, but nothing for the rig itself.

Thanks for the reply.

[ENGINEER]

I have a COMPLETE set of as built schematics for my 2017 Mirada. All you need to do is contact Coachmen customer service and provide Year, make, model and serial number. I received ours the same day via email..all OEMs are required by NTSB to maintain them.....some OEMs charge but Forest River did not, in our case. Good luck!...

Originally Posted by TheWolfPaq82

As far as a "Official" diagram for the trailer/coach layout...they don't make them. You'll find diagrams for your inverter, converter, but nothing for the rig itself.

[Photo Lab]

Part of your problem may well be a "non-problem". First, the incoming 120 volt power source must have the neutral (white) wire bonded to the chassis, and the ground wire (green or bare) must also be connected to the chassis. This is done in the breaker box, Although the ground wire may well be bonded to the chassis in multiple places, the neutral wire is bonded to ground only in the panel (breaker)box.

About the spark when you connect the inverter DC side to the negative 12 volt supply, this could easily be the sudden charging of capacitors inside the inverter. this is normal. To safely check for the possibility of a short circuit, connect one side of a fair sized 12 volt bulb to the ground (negative) lead you plan to connect the inverter to, and the other side of the lamp to the inverter negative input terminal. If the situation involves charging capacitors as mentioned above, the light will dim significantly after a short while. If there is something wrong in the inverter, it will stay bright. I use a regular old sealed beam headlight bulb...it is a good load, and easily connected.
On the other hand, if you have one side of the lamp connected to the negative wire you plan to connect the inverter to, and touch the other lead to ground(chassis) and the light lights, there i definitely something wrong! The negative wire should be at the same potential as the ground (chassis) connection.

This all might sound a bit complex, although it really is straight forward, and would be my first choice, minimal tools required, troubleshooting tool. A volt meter by the way, is really handy in general, but quite useless in this case, as it offers almost no load to the circuit under test, therefore in the instance of checking for the possibility of the capacitors charging, the reading (roughly 12 volts DC) would drop off pretty much never. In cases like this, a light bulb is the best tool, better even than a test light, as the test light draws typically about 1/4 amp or less.

[wbemis]

Excellent synopsis. I did connect the ground wire to the breaker box ground to establish ground reference to the neutral buss. With the hot lead disconnected, I have 120VAC potential difference from the inverter neutral to that neutral buss in the breaker box. With no load, the inverter buzzed loudly and tripped. The 12VDC I got from the DC feed to the AC neutral. Very disconcerting. Your thought of using a height resistive load (headlight) to establish the capacitive charge is a good one. I'll try that tomorrow.

[wbemis]

Originally Posted by ENGINEER

I have a COMPLETE set of as built schematics for my 2017 Mirada. All you need to do is contact Coachmen customer service and provide Year, make, model and serial number. I received ours the same day via email..all OEMs are required by NTSB to maintain them.....some OEMs charge but Forest River did not, in our case. Good luck!...

I will do exactly that, thanks for he insight. I'm really stuck until I can see their logic.

[ENGINEER]

Wbmeis....What problems are you experiencing? Photo lab's first sentence is more than likely correct. This, as described is a non problem, as if it was incorrectly wired you would be experiencing multiple 110V and inventor 12V battery issues. The schematic set from coachmen provides details of all 12VDC and 110VAC connections and interface points. It does not provide details on the OEM chassis...only terminations that were added by Coachmen.

[wbemis]

Not sure it's a non-prob but I see where you're coming from. I had a 3kv inverter wired in I that worked fine for several months. Then something changed and that inverter boss 4 internal fuses and did not restart after I opened it and replaced those fuses. I gave a more durable 2kw inverter that I'm using to troubleshoot the voltage variants but I'm trying to not take the entire system apart to test individual components. Thanks for your help.

[aquenichet]

Originally Posted by wbemis

2017 Coachman 31BH Class C. With the 30 amp AC unplugged and the main breaker open, I read 12 VDC from the + DC buss to the AC Neutral buss. I energized my portable inverter (case grounded to chassis) and with the ground and hot legs not attached, the neutral is a hot-short when I touch it to the neutral AC buss. Doesn't make sense to me. Any clues where I can get an official wiring diagram? Thanks to all.

I was told by Forest River that there was no way they were sending me a wiring diagram. It would be nice if we could all get an education from someone like photolab so we could fix our RVs. does any body know of a good manual that teaches this stuff w/illustrations. Hate not knowing.

[cavie]

call a licensed electrician.

[wbemis]

Originally Posted by aquenichet

I was told by Forest River that there was no way they were sending me a wiring diagram. It would be nice if we could all get an education from someone like photolab so we could fix our RVs. does any body know of a good manual that teaches this stuff w/illustrations. Hate not knowing.

I agree completely

[wbemis]

Originally Posted by cavie

call a licensed electrician.

Your thought is valid, but I retired as the General Supervisor over electrical planning and implementation in a Nuclear Generating Station with over 30 years as a journeyman electrician. I also hold certs in control circuitry and I'm accredited technical writer. I'm not sure who I'd call. I would just like to have proper circuit diagrams in my hands so I could troubleshoot with a plan. I will share whatever I learn from this adventure.

[ENGINEER]

Don't understand that. I sent an email with model and VIN and they sent me an 80 page schematic set....what model do you own?

[bikendan]

Originally Posted by aquenichet

I was told by Forest River that there was no way they were sending me a wiring diagram.

Remember, Forest River Inc. is a Corporation. It has different divisions, many were acquisitions that can operate somewhat independent from FR Inc.

Coachmen is one of these, along with Palomino, Shasta, Primetime, Shasta and Dynamx.
They probably chose to keep diagrams and share with customers, before FR acquired them. So they can continue that practice.

[wbemis]

I hope you're right. Thanks

[wbemis]

Got an excellent troubleshooting suggestion to wire in a light bulb between the inverter and the nuetral buss to see it that 120VAC potential bleeds off under a resistive load. That 100 watt incandescent bulb is shining brightly for an hour, no dimming at all. No other wires landed anywhere from that inverter. I grounded the inverter lead to the ground buss in the breaker box and got the same result. Getting stumped.
Result

[wahoonc]

I emailed Coachmen for a copy of the electrical schematic for my Concord 300DS and they promptly emailed me a copy. Six pages total, 2 for the chassis plan, 2 for the 120v and 2 for the 12v. I printed them on 11x17 sized pages for easier reference and markup. As far as getting a regular electrician involved, I would take that one with a grain of salt. Most residential type electricians I know are not well versed in the RV dual voltage systems. In fact if you follow the forums a fair number seem to have problems differentiating between a 30 amp 120v system and a 220v, based on the number of reports of people blowing converters and other equipment due to a mis-wired 30 amp plug added to their house.

Aaron

[wbemis]

Originally Posted by wahoonc

I emailed Coachmen for a copy of the electrical schematic for my Concord 300DS and they promptly emailed me a copy. Six pages total, 2 for the chassis plan, 2 for the 120v and 2 for the 12v. I printed them on 11x17 sized pages for easier reference and markup. As far as getting a regular electrician involved, I would take that one with a grain of salt. Most residential type electricians I know are not well versed in the RV dual voltage systems. In fact if you follow the forums a fair number seem to have problems differentiating between a 30 amp 120v system and a 220v, based on the number of reports of people blowing converters and other equipment due to a mis-wired 30 amp plug added to their house.



Aaron

Solid answer and great suggestions. Thanks.

[wbemis]

Solid answer and great suggestions. Thanks