PO did a terrible rewire (and other wiring questions)--Viking Deluxe 180

Discussion in 'Wiring' started by PopUpLarge, Jul 26, 2019.

  1. PopUpLarge

    PopUpLarge Member

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    Okay everybody, I need your help.

    I have a 1991 Viking 180. I have a few issues that I think are adding up to a pretty major overhaul of the 12v wiring, but with no wiring diagrams available from the manufacturer (too old) I need any help you folks can offer. Please note my electrical knowledge is pretty limited (I have a couple friends who know what they're doing teaching me). The only 12v we had when we got it was the two ceiling lights and the outside light.

    Making things more complicated: the PO clearly did a rewire at some point (along with a lot of other questionable remodeling I've been correcting) and no wire colors match properly. For example, the connection to the battery is black: positive and white: negative.

    Issues:

    1) We recently installed a switch panel running 4 USB ports and 2 cig sockets. Connected into the 12v line coming out of the converter. My plan was to run a small (400W) inverter from one of the cig sockets just to power a box fan at night and other occasional AC needs. However, we aren't getting enough juice through the inverter to power the box fan. We then attached the inverter directly to the battery via alligator clips and got plenty of power. Attached it to the spot where we wired in the switch panel by the converter, very low juice again. DID NOT try to connect to the wiring before the converter.

    The current wiring is pretty thin wire. It looks 14 gauge or at max 12 to me. Could this issue be caused by insufficient wire capacity? Or could the converter somehow be impeding the flow of 12v?

    2) I have the fairly common issue of tail lights dimming when braking with TV headlights on. I know the common solution to this issue is a loose/dirty/bad ground, but is there some place specific I should start looking? I had the back end off and the PO made spaghetti back there with multiple connector clips between wires for no apparent reason.

    3) On the back of my converter where the 12v wiring comes out, there's a single wire (it's blue but no idea if that's original or not) that leads nowhere. Jut has a cap taped on it, not connected to anything. Any guesses as to what this is?

    I would really appreciate insight into my specific issues, any wiring diagrams either standard or brand/model specific, etc. If it comes to a full re-wire, I feel like I can't just recreate what the PO did with better gauge wire because I have no idea what they did/didn't bypass.

    Ideally I want to add a second battery in parallel, solar, and electric brakes, but I'm just not sure if the current wiring setup is good enough to do that.

    Thanks for the help.
     
  2. eoleson1

    eoleson1 Well-Known Member

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    So to start with, the black positive, with negative at the battery is actually correct. RV manufacturers do this on a regular basis. It's probably to to mimic 120 volt wiring, where black is hot and white is neutral.
    1) you need to measure voltage coming from the converter to see if you really do have 12 volts there. Then you should measure resistance from the ground side of the socket to the frame of the camper.

    2) start by looking at the main ground from the pigtail.

    3) might go to a non existent appliance - furnace, water pump, refrigerator, etc. Blue from the converter should be 12 volt positive.

    While I don't have a diagram for your Viking, I have one for an older starcraft which might get you in the ball park.
     
    Raycfe likes this.
  3. PopUpLarge

    PopUpLarge Member

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    Thanks for the quick response! (And keep them coming folks!)

    Yes, would definitely appreciate the older starcraft diagram. Forest River currently makes Vikings via the Coachman brand, but was not the manufacturer in 1991 (maybe that was coachman independently? I can't find on google right now).

    Interesting to know about the black/white thing! So maybe some of the wiring is original...it really gets confusing under the back cowl, as there's just random connectors/splicers for no apparent reason. That wire is red and white with some black (only leading to the license plate lights. And all of it is pretty small gauge. How thick are your battery wires?

    Follow-up question: if there's an issue with the main ground (#2) could that also be causing resistance issues and thus lower power (#1)?

    RE: #3--the only appliance we have is a fridge and I haven't figured out if it works yet or not, tried the pilot light a couple times and it didn't come on, I'll take a closer look. It might be that it's completely disconnected from 12v as well.
     
  4. SteveP

    SteveP Well-Known Member

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    A good start would be to identify the make and model of your converter and look for the installation instructions online, they will tell you what the wiring/circuits at the converter should be.

    There should be a ground connection on the driver side of the A frame near the tongue and at least 1, probably more, on the inside of the frame near the converter. I would expect the ground for the taillights to be on the inside of the frame near the driver side rear corner.

    The voltage drop at the converter may be due to undersized wire but more likely due to corroded connections due to the cheap Scotchlocks and wire nuts used in assembly or to a bad ground.

    12 gauge should be big enough for everything you've mentioned trying to run so far except maybe the inverter. Is there a reason that you're trying to run a fan off of an inverter rather than plugged in to a 120 vac receptacle?
     
  5. PopUpLarge

    PopUpLarge Member

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    SteveP: Sorry if I was unclear, just need the inverter for instances when we aren't on shore power. The inverter will not be used when shore power is available.
     
  6. PopUpLarge

    PopUpLarge Member

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    Oh also, are you saying that using 12g wire and tons of scotchlocks was standard in manufacture assembly?
     
  7. SteveP

    SteveP Well-Known Member

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    Seems to be. I was replacing my taillights a couple of days ago and did away with 6 of them. I don't think I really needed the new taillights, just the new connections. Seems like every time I touch the wiring I'm cutting out a scotchlock.
     
  8. eoleson1

    eoleson1 Well-Known Member

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  9. PopUpLarge

    PopUpLarge Member

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    Cool thanks!

    Any thoughts on whether finding my ground problem will clear up my power output to inverter problem?
     
  10. mpking

    mpking Well-Known Member

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    It probably won't. It's a wire gauge issue. A 400W inverter is probably going to need 8 gauge wire (or better). If you run the wire any distance, you'd probably need #2 or even #0.

    I know @rabird and @roybraddy known wiring better than I (Paging them). You'd need to figure out the power draw, and the distance you need to run the cable (Short the better) and then plug it in to a calculator.

    As for the Fan, Don't run the fan off the inverter. Get a 12Volt fan. Will save you alot of battery power.
     
  11. PopUpLarge

    PopUpLarge Member

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    So there's no wiring at all on the driver's side, everything is routed from the passenger side of the A frame and then along the inner frame support to the back. Still haven't found any ground to the frame at all.

    RE: inverter, I picked up a 12v fan so that settles that part of the problem. I also repurposed some heavier gauge wire for occasions when we'd actually need the inverter and I'm going to run it straight from the battery.
     
  12. Raycfe

    Raycfe Waterford Ct.

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    You can connect the ground wire any place(s) to the frame as you want. Usually there is one near the battery and one near the rear crossmember.
     
  13. PopUpLarge

    PopUpLarge Member

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    20190805211900.jpg Okay, here's an update on my ground issue:

    I put her up on jack stands and traced the wiring from the harness connector all the way down the line. I found two ground spots. One is a piece of hard copper wire running from the back of the converter to the frame, which I assume is the AC ground.

    The other is in the attached picture.

    Hit both spots with contact cleaner.

    From that mess I followed the wiring all the way to the rear passenger corner. I haven't pulled the cowl off again but I can say with confidence that the white wire that runs into the cowl doesn't lead back to the frame.

    Ideas?
     

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