Just purchased, and have some wiring questions

Hi all

I am a new to me owner of a 1985 hi lo model 16 (?)

Just brought it home on thursday, and I am working through a few problems left over from the previous owner.

Besides having to get my truck set up with a 7 pin harness and brake controller, I also need to fix the wiring on the trailer.

The electrical that seems to be working is:

Power to pump - once I installed a battery, it raises and lowers with no issues.
12V water pump - when I turn the switch on, the pump runs
inverter - when I plug in 110V, I can hear it click and start to humm (haven't tested it any furthur than that)
All 110V interior plugs work - except fridge plug

The electrical that does not work that I need help with

All lights inside, except for the 2 lights right at the front of the trailer on the wall. I have not even checked the bulbs yet, but there's wiring problems I will show below that I want to tackle first

Exterior light at door inop
Bathroom fan inop
110V outlet for fridge (behind fridge through exterior access door) dead

I have stared at the wiring diagrams, and haven't been able to figure out why all the 110V plugs would work, but the one behind the fridge does not.

I can't get the fridge to come on, but it looks in very poor condition, and may just want to remove it completely and install a 110V bar fridge with inverter.

Other than the fridge, I need to tackle the spagetti of wiring up at the battery box. Below are a few pics of what I am dealing with. I can clean up and repair all the wiring that is still connected, however there are some wires just hanging there that aren't connected to anything, and I'm not sure where they should go.

I also have to make sure the electric brakes are working, I can't seem to locate the break away pin, unless it's the black thing that has a bunch of what looks like house wiring coming out of it.

I am confident in my wiring ability, just need help with the identification of the wires.

Thanks for any help. Below I am attaching a few pictures of what I am dealing with, and a video running through the battery box.







Here's a link to to the video, may be easier to see


‪Video 11 07 30 3 19 14 PM‬‏ - YouTube

Also, here are the pics of what I think is the break away for the brakes

That all looks like a helluva mess. First, go buy a new breakaway switch and get it mounted with the cable end pointing to the hitch. Start separating the wiring by starting with the seven wire cable from the TV cable. Get everything else out of the way and try to get everything properly connected at the terminal strip. There should not be any 110 volt wiring in the battery compartment. It looks like you have bad insulation on some wire, replace it, and get all that taped up stuff out of there. Make sure you have two circuit breakers in there somewhere, one for the lift pump and one for the house wiring. I believe the wiring diagrams give color coding so you will have to run with that.

After that, trace your 110 volt wiring into the trailer and locate the fuse/breaker box. It may be separate from the converter (not inverter) but will have wiring going to the converter for the 12 volt circuits and battery charging. Check all breakers and fuses. This is a good time to have a volt meter to check for energized circuits.

Just break things down to the simplest form and go circuit by circuit.

Check the outside compartment on the side or front for a cable that plugs in to the top half of the trailer. The newer trailers have a cable inside the bathroom that provides power for the various lights and bathroom fan. I'm not sure when they were brought inside but the older trailers have an outside cable, either under the front window shield or on the side. Some are alwatys connected and others need to be plugged in when you get to your destination.

Ya, I figured that was the best way to do stuff, just wondered if I was missing anything.

Started with the 7 pin wiring cleanup this afternoon.

Electric brakes are new to me (Upgrading from a bonair pop up tent trailer with no brakes)

Other than wiring it into the break away switch when I get one this week, is there any other wiring that it's supposed to be connected to?

The previous owner had this wiring all screwed up. Looks like he confused black with ground, and had the white and black connected together, and added the solid copper house wiring.

I obvously cut all the house copper out of the battery box, and rewired to a new 7 pin block, but there was another wire spliced into the blue wire too, was pushed beside the grommet out of the box and under the trailer.. I have to try to trace that tomorrow, definately doesn't look factory installed.

Just confirming, the blue wire from the 7 pin harness connects to the blue wire that travels up the coil wire with the rest of the wiring to the top of the unit correct?

This is where I'm at so far:

Normally, in today's wiring, the blue wire is the brake wire. I don't think it would go up to the top, rather it should head underneath and straight to the brakes. The breakaway switch hooks to the battery and to the brake wire.

I'm going to have to look at it closer tomorrow, as it was getting pretty dark.

Looking at the wiring diagram, the coiled harness going to the top section does not show a blue wire at all.

Maybe the previous owner pulled the other wires out of the lower harness to repair them and never put them back properly.

Anything is possible. One thing to check while you are at it is make sure the wires to the trailer plug are properly hooked up, according to standard wiring procedure, to make sure it matches the wiring on the tow vehicle socket.

Her is some good info on that: Trailer Wiring Diagrams | etrailer.com

So had to back track a bit, some of the colors in the wiring diagram don't match.

I do indeed have a blue wire heading up the coil to the top compartment, but I do not know what it's for.

I jumpered and applied 12V to it, and then checked everything inside.. It appears to do nothing.

I seperated the trailer wiring and all the other wiring into 2 seperate connectors, taped up all the wiring, as some of the insulation was deteriorated, but I did not have enough slack to cut it out, and will plan on replacing it down the road.

I located a blue and white wire headed to the brakes, crawled under and found a rats nest of cut/chopped wiring under there too. I will have to get it up on jack stands and pull the tires and repair that wiring at some point, so for now I left the brake wires disconnected, because when I tested them by applying 12V to the blue wire and ground to the white wire, it sparked pretty badly.

I put loom on all the exposed wires and secured it all to the bottom of the trailer.

Unfortunatly, the inside lights still do not work, I have now tested with a test light, and there is no power there, except for the 2 right at the front of the trailer, so I must have some additional issues inside the trailer.

I'm wondering if the blue wire in the coil at the front is the mysterious "stereo wire" that is referenced in the manual. It lists that wire as a yellow wire, but the only yellow wire in that harness was for the reverse lights, which it also lists, but as a different guage.

Anyhow, that's my update for today.

Thanks for the tips everyone.

Ok, so I've got everything finished, and working 100% (sort of)

All trailer lights work, I serviced the brakes, repacked the bearings, and then decided the rats nest of wiring to the brakes was too bad to bother to repair, so I ran new wiring up both sides of the trailer into the front battery box, installed a new break away switch, and all the brakes work perfectly.

Onto the interior lights.

I cannot find where the wiring for the light over the kitchen, the light in the bathroom, and 2 of the lights on the side, and the exterior door light run. I have come to the conclusion that they must run behind the walls somewhere, and I cannot locate them.

Anyone have any suggestions before I simply run new wiring on the inside of the walls and cover it with some kind of trim?

The 110V plug for the fridge is in behind the kitchen cabnets, and I'll have to get that rewired too, but I accessed the fridge from the rear compartment, and plugged the fridge directly into an extension cord. Set the dial to 110V and left it. The fridge is NOT working in 110V mode. Checked in 12V mode. Have voltage, but no workey either. I have not tried it in LP mode, because I want to have the LP system checked before I use it.

Am I safe to assume this fridge is dead (won't even run plugged directly in, bypassing the trailer completely)

I won't lose any sleep over pulling this fridge out and replacing it with a 110V model. I will install an inverter to run it while on the road, and I don't care about using LP.

Any thoughts on this fridge before I condemn it?

If the fridge is producing heat in the back but it is not cooling inside it has lost its charge of refrigerant, which is most likely ammonia. If so, you may as well go shopping for a new fridge. RV fridges have a short life as compared to normal in house ones.

The 110 volt inverter to run a 110 volt fridge will consume to much 12 volt power, it will run down the trailer battery in about an hour, or less, the tow vehicle wiring would have to be heavy and the alternator would have to be capable of supplying enough power, I think this idea would be a problem.
The electronics board in the fridge may be bad, the 110 and 12 volt coils could be burned out. There may be a fuse in the back of the fridge for 12 volts to the board that might be bad. Is the temperature control set to about 4?
Just saw RichR,s post and he is right check for heat at the vertical tube where the wires enter for heat. I for got this.

It doesn't do squat. Doesn't make a sound, doesn't make heat, doesn't get cold. It's as if it's not even turned on, but I've used a meter to check, it has voltage right into the back of the fridge. I haven't tried to disassemble the fridge it's self, but I'm not really interested in doing that. The inside of the fridge is in poor condition, the shelves are all rusty etc...

I run an inverter in the back of my truck and it will run a small cube fridge fine. I wired the truck with 8 guage stereo power wire to the back, and then 12 guage wiring through the harness connecter to the 12v supply in the battery box. I think I should be fine running a 600watt inverter onboard, as I run a 400watt in the back of my truck now when we're on road trips.

I'll have to swap the plug from the inverter to the converter when I get to the campground, but that's not a big deal to do.


Anyone have any ideas on where the light wiring is run?

side wall wireing

On my 88 22l, the tops light wires run in the wall just in front of the bathroom on the street side
tub wall and is your trailer level? this affected the fridge on mine, which still has the original fridge. it seems like 3 or 4 hours before my fridge gets cold, so I always turn it on a day before i go out so its ready.

After leaving the fridge plugged in to AC and turned on for a minute or so, pull the outside panel and find where the 2 heating elements go into the chimney. See if there is any heat coming from one of those elements. If the AC element is heating, then you know that isn't your problem. If it is cold, you may have another issue. Careful, it can get hot enough to burn you.

robobd, no the trailer is not level, as it's in my driveway. I know that would normally affect the performance of the fridge, but would it cause the fridge not to come on at all?

fireballsocal, I'll try that and report back. I suspect it will be cold, as I had it plugged in for several hours before I went back and started testing voltages, I think I would have noticed if something was warm, but I wan't watching for that, so you never know.

RV refrigerators are ammonia gas, no moving parts except the gas, the ammonia returns to the heating unit by gravity, depending on how much out of level the ammonia can't return, and will not cool and damage to the cooling unit will occur.

Morpheus, on my fridge there are two fuses on the control board on the back of the fridge in the black box. Make sure they are good. Their is also a 30 amp fuse behind the fridge and one owner has said on his HiLo this fuse had been covered over by the expanding foam. Make sure this one is good. The control board could also be bad and is cheaper than a new fridge. When you turn on the fridge do the lights on the front panel light up? My coils on the back of the fridge do get warm when the fridge is working. Fireball is correct that the area on the chimney around the AC and DC heating elements should be hot. Having the RV reasonably level is important for good operation and can destroy the fridge if way out of level. With nothing working it looks like no power is getting thru the control board. Good luck.

FYI, I fixed the lights in the kitchen and bathroom.

I found the broken wire behind the left tail light. That's where the main harness comes into the back, and the black wire goes up into the cieling.

Right in that corner there was a junction where the bathroom fan/light and kitchen light wires connect. It was corroded out.

Fixed the connection, and all of the above started working.



Then the bathroom fan exploded....

My fan did just the same thing about 2 months ago. Good excuse for a fantastic fan.