Engine won't turn off with trailer connected

[keef95]

Originally Posted by l1v3fr33ord1

Chris ("keef95")-

If you plug the trailer into the coach, and without the ignition being on, does the trailer electric brake controller show signs of having 12V power (for instance, does the display light up)?

I’ll have to look at the controller display tomorrow to answer. When I plug the trailer into the coach, I hear activity in the engine bay as though the key was turned on... sounds like solenoids and relays cycling.

I did test for voltage out of the brake circuit on the trailer when not connected to the coach and there is none.

[Almost There]

I have heard of this before and apparently not uncommon.
I believe usual fix is diode installed. Sorry, I can’t tell you the size

[YC1]

Yep, cut it loose and find another source.

You could control that line via a relay but I prefer to have mine charging all the time. Just simpler. I use a breaker and not a fuse in case I do something dumb so it just resets itself.

I found a nice power connection in the right rear compartment.

[TonyMac]

Originally Posted by keef95

I truly appreciate your replies and insights. As I used the stock wiring (prewired) loom from Monaco/HR it gets a little more involved to find where they sourced the charge circuit from.

I did test the trailer and the only pin I'm finding "hot" is the charge pin...

It is very strange that disconnecting the trailer brake wire stops the problem though. If there was power coming back through that wire one would assume the brakes would be locked...

Dude, this is messed up like a football bat.
1) I doubt seriously the quality of Monoco, because I own one. The assemblers are union wage, could care less clowns, and I have 40' of proof. Good grief man, they put my shower valve on upside down and used a 3" screw when a 1/2" screw was called for. I could go on for hours about the "quality" of the Monoco build. They used 1/8" flooring in my washer/dryer compartment. They can't shoot a staple straight.
2) Your trailer plug should be cold when unplugged, no hot pins at all, ever. You do need a diode in your charge line, who built that? But the question is, how is the battery bank in your trailer powering the engine in your motorhome. I believe your battery bank is being charged by power from your fuel pump line, and when you remove power to that line by shutting off the key, the battery in your trailer supplies power to the pump. This means you have too much draw on that circuit and the pump is not getting the full load it may need. And it's French-kissing-your-sister wrong. Your battery charge line should be a separate circuit.
3) Why would the brakes lock? Your battery is not connected to your brakes until you pull the breakaway pin (which you should do now and again to test). You have a pin in the plug that supplies power to the brakes, and another pin in the plug that charges your battery. This logic is flawed.

It's a simple fix. Electric motors hate running on low amps.

[RamiDav]

This relay or any common auto relay should work .
This one has a lug for mounting .

https://www.etrailer.com/Accessories...%20and%20Parts

The wire from your ignition along with a ground wire will
operate the relay coil
The contacts are to interrupt the elect flow between the coach batteries
and the trailer battery when the key is off .

A scenario where a light was accidentally left on in the trailer this would
save your starting batteries

Ray

[keef95]

Originally Posted by TonyMac

Dude, this is messed up like a football bat.
1) I doubt seriously the quality of Monoco, because I own one. The assemblers are union wage, could care less clowns, and I have 40' of proof. Good grief man, they put my shower valve on upside down and used a 3" screw when a 1/2" screw was called for. I could go on for hours about the "quality" of the Monoco build. They used 1/8" flooring in my washer/dryer compartment. They can't shoot a staple straight.
2) Your trailer plug should be cold when unplugged, no hot pins at all, ever. You do need a diode in your charge line, who built that? But the question is, how is the battery bank in your trailer powering the engine in your motorhome. I believe your battery bank is being charged by power from your fuel pump line, and when you remove power to that line by shutting off the key, the battery in your trailer supplies power to the pump. This means you have too much draw on that circuit and the pump is not getting the full load it may need. And it's French-kissing-your-sister wrong. Your battery charge line should be a separate circuit.
3) Why would the brakes lock? Your battery is not connected to your brakes until you pull the breakaway pin (which you should do now and again to test). You have a pin in the plug that supplies power to the brakes, and another pin in the plug that charges your battery. This logic is flawed.

It's a simple fix. Electric motors hate running on low amps.

1) It’s my first motor home but have had few trailers including “luxury” fifth wheel toy haulers. I’m good with the quality of my HR... it’s a pretty nice machine. Sorry yours had issues.

2) I agree the charge circuit should be separate. As for the trailer plug being hot... I’m finding power on the contact that goes to the batteries in the trailer. If this isn’t supposed to be the case then it would indicate the absence of the aforementioned diode.

3) I’m not talking about the break away battery but rather the pair of deep cycle batteries powering the lift and jack. Please refer to my opening post... if I unplug the wire (in the HR trailer connector) that powers the trailer brakes from the controller that is separate from the other 6 that reside in one connector, the issue goes away.

[keef95]

Originally Posted by RamiDav

This relay or any common auto relay should work .

This one has a lug for mounting .



https://www.etrailer.com/Accessories...%20and%20Parts



The wire from your ignition along with a ground wire will

operate the relay coil

The contacts are to interrupt the elect flow between the coach batteries

and the trailer battery when the key is off .



A scenario where a light was accidentally left on in the trailer this would

save your starting batteries



Ray

Thank you Ray!!

[l1v3fr33ord1]

Chris-

I believe there's a mis-wire, and that you'll be able to find and fix it. Unless you are under the gun, a workaround may not be needed. I make it my goal to get the factory-installed wiring working as designed. You're already ahead of most by putting the 7-pin connector aright and using a plug-and-play harness at the dash end.

A place to start is at the connector feeding the brake controller. After you get the answer to the question in my previous post, you should disconnect the controller and measure the signals on those pins.

Also, there's this to consider: Around 2006, Monaco installed the wiring on a relay involved in this circuit improperly. They put out a bulletin on this, and how to fix it. It is possible that mistake may be involved in the symptoms you are seeing.

[keef95]

Originally Posted by l1v3fr33ord1

Chris-

I believe there's a mis-wire, and that you'll be able to find and fix it. Unless you are under the gun, a workaround may not be needed. I make it my goal to get the factory-installed wiring working as designed. You're already ahead of most by putting the 7-pin connector aright and using a plug-and-play harness at the dash end.

A place to start is at the connector feeding the brake controller. After you get the answer to the question in my previous post, you should disconnect the controller and measure the signals on those pins.

Also, there's this to consider: Around 2006, Monaco installed the wiring on a relay involved in this circuit improperly. They put out a bulletin on this, and how to fix it. It is possible that mistake may be involved in the symptoms you are seeing.

Thank you for attention on this. I too am a stickler for “clean” and “correct” on any installations or modifications I do and agree with your assertions.

Going last to first...
I recalled the bulletin you spoke of and found that in fact my trailer relay was incorrectly wired and moved the wire to the correct pin but didn’t have time to test it and will today. (RV stores in one shop, trailer is in another).

Before building the connector to use with the factory harness I tested continuity of the brake wire from front to back as I didn’t want to get done and find that circuit was not what I expected but will test again. The factory harness in the coach was very straight forward and seemed correct. 1 ground, 1 constant 12V, 1 switched 12V, 1 brake signal and a heavier (guessing 12 gauge) trailer brake wire. The hardest part was finding the other side of the OEM connector.

Not under the gun at all so will work through it. The Cargo Mate trailer was a good value but workmanship is a little questionable in some areas. As everything works perfectly on a trailer without automotive batteries in the picture, I’m guessing I’ll find the solution lurking around there.

Will report!! Thank you!!

[YC1]

Chris, it sounds like you have it nailed.

Mark, that was a great tip on the recall. Getting it to work like the factory meant it too is the way to go.

With it working as the factory intended I found the charge line just did not supply enough to my toad. The power goes though a lot of small wires having to go through the umbilical and all the connections.

I installed a separate charge line that is hot all the time and has a breaker on each end. It is connected close to my battery bank.

IF you have a couple of batteries in the trailer and the power run is long you may find the charge voltage a bit wimpy. Of course a clamp on meter at the battery and a voltmeter across the terminals will give you the story.

It sounds like you are very handy with the voltmeter so taking these measurements should be routine maintenance. Things wiggling about cause loose connections so keep a close eye on those trailer batteries.

[keef95]

Originally Posted by YC1

Chris, it sounds like you have it nailed.

Mark, that was a great tip on the recall. Getting it to work like the factory meant it too is the way to go.

With it working as the factory intended I found the charge line just did not supply enough to my toad. The power goes though a lot of small wires having to go through the umbilical and all the connections.

I installed a separate charge line that is hot all the time and has a breaker on each end. It is connected close to my battery bank.

IF you have a couple of batteries in the trailer and the power run is long you may find the charge voltage a bit wimpy. Of course a clamp on meter at the battery and a voltmeter across the terminals will give you the story.

It sounds like you are very handy with the voltmeter so taking these measurements should be routine maintenance. Things wiggling about cause loose connections so keep a close eye on those trailer batteries.

Thanks!

We’ll see on the recall as my trailer wasn’t exhibiting the symptom described in the bulletin.

I am interested in TonyMac’s thoughts that the charge line is sourced correctly so will look at amp values for changes that don’t make sense on that circuit with fuel system on and off.

The batteries in the trailer only run the lift and jack. Batteries get used very little so light charge line is okay. Airplane in, lift up, car in, long drive, car out, lift down (no power used), repeat and I use a battery tender on everything I own when stored.

Read a lot last night on diodes to prevent back feeding power and if there isn’t one on the trailer it’ll have one asap.

[RamiDav]

Chris ,
An airplane ?? WOW , I see coaches all the time with a big ole trailer
and often wondered what that person has in there but never thought
an airplane , now that's cool .

How about some pictures ?

As this thread goes along I see that you are more knowledgeable than
I thought .
You will be helping the helpers soon .

Just be sure you incorporate large enough wires protected by breakers
or fuses .

Ray

( Airplane in, lift up, car in, long drive, car out, lift down )

[keef95]

Originally Posted by RamiDav

Chris ,
An airplane ?? WOW , I see coaches all the time with a big ole trailer
and often wondered what that person has in there but never thought
an airplane , now that's cool .

How about some pictures ?

As this thread goes along I see that you are more knowledgeable than
I thought .
You will be helping the helpers soon .

Just be sure you incorporate large enough wires protected by breakers
or fuses .

Ray

( Airplane in, lift up, car in, long drive, car out, lift down )

"More knowledgeable than you thought" is very gracious of you but thanks!

To address the "not shutting down" portion before "show and tell"... Trailer relay service bulletin didn’t change anything. Everything checks out fine on the coach wiring and when I remove the fuse in the charge line to the trailer accessory batteries, all is well and coach shuts down connected to trailer so it is a "back feed" issue. I could change the source for the accessory charge directly to the battery and am sure that would solve the problem but as mentioned, these batteries, between the jack and lift see so little action that I'm going to try installing a diode. I'll report and let you all know how it goes...

Airplane makes it sound more extravagant than it is... It's a light sport aircraft of the type I've been flying for 25 years. Google "P&M Quik GTR". I was hauling the plane in my 5th wheel toy hauler but came to Class A RVs because I want to take my car as well...

[keef95]

Wanted to report back... I put a Roadmaster diode between charge line and trailer batteries and problem solved. Charge line puts out 4.5 amps so will charge without the worry of baking my batteries.

Thank you all so much for taking the time to post your opinions!

Blue skies!
Chris