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Lordraptor1 · 03-25-2023, 01:19 PM

ok so i have been racking my brain on this one as it does not make any sense whatsoever how this thing seems to be wired for the head, tail, dash, and clearance lights and im hoping someone might have an answer.

ok keep in mind this is going to be a long post with lots o reading while i try to be as accurate as possible LOL.

motorhome is an 1987 pace arrow eleganza on a john deere ( oshkosh/freightliner) chassis with ford 460.

ok, so i DO have turn signals, voltmeter needle move when key is turned on, blinker indicators work, and brake lights work, and it cranks and gets spark ( doesnt start but i suspect this is because there is only 10 gallons of fuel in it and it isnt enough for the external carter fuel pump to pick up out of the tank). nothing else regarding exterior lighting or dash lighting/radio.

so with the problem laid out, here is how this thing is/was wired.

black wire off load post of aux? chassis/coach latching relay through firewall connector turns into black/brown stripe with a spade connector on it which goes to a 40A normally open relay.

yellow wire off load post of aux? chassis/coach latching relay through firewall ( stays yellow) to the bus connected to the stop/haz, horn, and tail light fuses.

brown wire (connects/has continuity to multiple locations on through firewall plate and ignition switch) has spade clip to connect to 40A normally open relay.

green wire off dimmer switch has spade connector goes to 40A normally open relay

orange wire off rocker light switch which gets continuity on both switch on positions has spade connector goes to 40A normally open relay.

2x white wires has spade clips to go to 40A normally open relay

red wire with spade connector off headlight switch ( gets continuuity on one of the on positions of switch) goes to 40A normally open relay

red/black stripe goes to tail light fuse

red/yellow stripe (off floor dimmer switch) has spade connector goes to 40A normally open relay.

under the dash are 2x 40A normally open relays which is where the above wires are suppose to connect to.

so knowing the above i have 2x questions.

1. does anyone have any idea what wire connects to what pin on which of those under dash relays? ( want to make sure those connections are correct and if not fix them.)

2. does the motorhome need house batteries before the exterior and dash/horn/radio/emergency flasher work? at this point i am assuming that might be the case seeing as how the power lead to the tail,horn, and emergency flashers come off the load post of the aux? relay and the house bats are shot and the house bat cables are bad and disconnected.

yes i di have factory chassis schematic ( several for hte same vehicle in fact) but NONE of them are actually accurate as deviate from actual practice most notably the floor dimmer going through a realy under dash and only the instrument cluster dimmer is used on the stock ford light switch

any info would be helpful.

MrMark52 · 03-26-2023, 08:03 AM

Watching

astrnmrtom · 03-26-2023, 11:53 AM

Quote:

"2. does the motorhome need house batteries before the exterior and dash/horn/radio/emergency flasher work? at this point i am assuming that might be the case seeing as how the power lead to the tail,horn, and emergency flashers come off the load post of the aux? relay and the house bats are shot and the house bat cables are bad and disconnected."

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Easy enough to test. If you have a good starter battery - and it's the same voltage as the house battery - swap it with the dead house battery and see if that circuit comes alive, or use jumper cables to connect the house and starter battery cables together.

153stars · 03-26-2023, 11:58 PM

Some posts have too little info other it's hard to sort through .
GM for many years stacked pos cables on the starter and had a fusable link to smaller cable. Fixed so many GMs. Not sure if Ford did similarI would not attempt a hooking up a starter without sanding, wire brushing or scraping with a rock if I had to those two cables ,no mater how clean they looked. If not 50-50 you would get on tiny click and nothing. Crawled under a couple MHs got them running for same issue. Always suspect bad ground/s as well.
Also old MH hard to know if some hack did hacking grabbed a positive from house batts. Fix the cables put some 12v battery in there for now see what happens
Be on look out for self resetting can thermal fuses with studs and nuts. Old MHs used a lot of spade connectors to relays and lots of other stuff they get dirty and don't connect.

Joyce M · 03-27-2023, 02:10 AM

Good Luck!...The 12 volt system in my '88 P30 went tits up last August.
I have one chance left for a shop to fix it. At least he said he would do his best.
With the snow I have been dealing with next week will hopefully work out.
I lost high beams-markers-tail-brake-4 ways-charging and all dash items.Oil-fuel-charging etc.
Just keeping my fingers crossed, $5K in new stuff in the last 2 years, no way I can just trash a friend who has given me and my late wife such fun since 2006.
I'll be watching you and if My tech works out I'll give you his #.
I'll never buy any motorhome again..They will sell you one but no one will work on them.

153stars · 04-08-2023, 07:16 AM

How do tell a MH owner at a campground he's the walking around with tools in his hand.
EDIT Already in earlier post more applies to you as you have nothing basicly
Old GMs had main positive branched off the starter as well as a fuseable link there. So two or three cables on pos. on starter. I've crawled under many GMs to clean that stack of cable lugs to restore power.

Quote:

Originally Posted by Joyce M

Good Luck!...The 12 volt system in my '88 P30 went tits up last August.
I have one chance left for a shop to fix it. At least he said he would do his best.
With the snow I have been dealing with next week will hopefully work out.
I lost high beams-markers-tail-brake-4 ways-charging and all dash items.Oil-fuel-charging etc.
Just keeping my fingers crossed, $5K in new stuff in the last 2 years, no way I can just trash a friend who has given me and my late wife such fun since 2006.
I'll be watching you and if My tech works out I'll give you his #.
I'll never buy any motorhome again..They will sell you one but no one will work on them.