RV Trailer Control Issue?

[Folson]

Hello 2x I have had this issue. Hook up the RV and arrive, disconnect etc. 3 days later go to start truck Dead battery. Jump the truck ,hook up go home disconnect park RV . Again I thought the battery or the kids left something on. But when this happened the first time went ahead and changed the Battery (bat was 4 years old) Now same exact situation 1 year later. Also this is 2 different RV' trailers. Checked voltages on the Truck conn. Found at the 1:00 position 12V and 13V at the 5. The 1 is the Batt Charge I believe but the 5 is the Brake controller. All the other positions 0. My question: is the Brake Cont. position on the connector, suppose to have voltage all the time ? or only when the brakes are applied. What's even more puzzling is that after the truck is jumped, RV towed, parked disconnected I can park my truck and use normally even after several days and no issues. Almost seems that the controller is somehow intermittent causing a battery drain? The truck conn ? or perhaps the truck wiring itself? The controller led is not on when the Trailer is not connected.

[moose074]

Ok so I got lost half way through but that’s just a communication problem. You should post your trucks make and model. So others have the info to reply. In my experience you should be having around 14 volts on your truck gauge if your reading off your dash . If you put a voltmeter on your battery truck off you should be reading 12.6 ish. Start the truck retake should be 14 ish. Or you can take your truck to oriellys, advance auto, ect. They can test your battery and alternator same time. If I didn’t help with this I apologize

[Folson]

Hello Thank you. 2013 Dodge Ram 1500. Battery charges and shows 14V I know it may be confusing how I may be presenting. But this only happens when the RV trailer is used, What is confusing same symptom 2 diff RV trailers. New Battery based on the first failure. It only appears to be happening as explained.
Thus asking if the Brake controller at the connector on truck 7pin is suppose to be hot all the time. Plus wondering if it could be intermittent somehow between the brake switch wiring and brake controller? Update I disconnect the controller and no voltage at 7 pin. as it should.

[Folson]

Hello I have this posted elsewhere but thought i'd try here also. My symptom is that for 2 years running when I disconnect the RV Trailer (18RR) after 3 days my battery is dead on the truck. This happened last year and figured a old battery but now its only 1 year. Anyway when I measure V the 1:00 pos has 12.7V but also the 5:00 pos (this is for the Brakes) From what I understand the 5:00 pos should not have V until the brake pedal is applied ? But in talking with a service tech basically stated no draw on the connector so it shouldn't matter. Anyway the V go away when I disconnect the Brake controller as it should on the 7 pin but the other pin still has 12.7 (1:00). Changed the controller same V readings.Chnged truck conn same V. When I disconnect the Controller and measure the connector from the truck 12v Blk 054Vred,white and blue 0 (truck off). When I depress the brake pedal 12V Blk,12V Red,0 white,0 Blue.(truck running) Is this a reversal coming from the truck? Isn't the Blue for Brake? Anyway on top of that after I park the rv at home and use the truck I can leave it sit for a week and no problem? It appears that it will battery drain if I let it sit after parking but after parking and then use within 24hrs the truck can sit with no issues? The service dealer suggested a battery disconnect to stop the fathrom drain? Very confused

[Trksr]

What truck do you have?

[Folson]

Thanks 2013 Dodge Ram 1500 Big Horn. Note that I replaced the connector (7Pin) and Controller.

[Folson]

There has to be some type of parasite drain after using the RV. As It only has happened when I use it. Otherwise the truck is fine. I've never tried letting the truck set after we get back as I always had used right away vs letting it set for a few days. But in saying that then when I do let it set for a long period it fires right up?

[cboss]

Originally Posted by Folson

Thanks 2013 Dodge Ram 1500 Big Horn. Note that I replaced the connector (7Pin) and Controller.

Did you have this issue before you replaced the plug and controller?
If you replaced the plug and controller because of the issue I'm sorry for the question.

[Folson]

Yes I was thinking that perhaps the old controller was defective and somehow causing a drain and /or the connector was shorting also. But went ahead and replaced and have the same symptoms.

[Tom48]

Originally Posted by Folson

Hello 2x I have had this issue. Hook up the RV and arrive, disconnect etc. 3 days later go to start truck Dead battery. Jump the truck ,hook up go home disconnect park RV . Again I thought the battery or the kids left something on. But when this happened the first time went ahead and changed the Battery (bat was 4 years old) Now same exact situation 1 year later. Also this is 2 different RV' trailers. Checked voltages on the Truck conn. Found at the 1:00 position 12V and 13V at the 5. The 1 is the Batt Charge I believe but the 5 is the Brake controller. All the other positions 0. My question: is the Brake Cont. position on the connector, suppose to have voltage all the time ? or only when the brakes are applied. What's even more puzzling is that after the truck is jumped, RV towed, parked disconnected I can park my truck and use normally even after several days and no issues. Almost seems that the controller is somehow intermittent causing a battery drain? The truck conn ? or perhaps the truck wiring itself? The controller led is not on when the Trailer is not connected.

Generally, the brake control leg should not have voltage unless the brakes are applied. If it has voltage then there is either a bad setting on your brake controller and it is set to sensitive or you have bad brake controller.

That on the other hand should not run the batteries dead if they are charged when you disconnect the trailer. On the other hand if the breakaway switch is pulled then the battery on board the coach will charge the brakes 100% of the time and you should know about that because they would overheat smoke and burn up.

Again all of the above by slight degrees could give you a problem with a lot of dead batteries

[fipntdot]

Can you activate the brakes with the controller only, similar to when you are testing the power level?

I would consider looking for a short in the truck wiring somewhere.

[Folson]

Thanks guys. I have the RV stored so not able to connect. Without having it connected is there a way to test the controller? Seeing I purchased a new controller and truck 7 pin I went ahead and put the new 7 pin on. As stated I still have volts at the Brake control pin. So I disconnected the controller. I am thinking it has to be the wiring from the factory? either way I figure to but a battery disconnect on the truck.(to eliminate any fathrom voltage) Unfortunately haven't figured out how to do as this truck battery connector is different. Its not just a regular round bat connector but a round one with 2 connections on it.

[fipntdot]

Originally Posted by Folson

Thanks guys. I have the RV stored so not able to connect. Without having it connected is there a way to test the controller? Seeing I purchased a new controller and truck 7 pin I went ahead and put the new 7 pin on. As stated I still have volts at the Brake control pin. So I disconnected the controller. I am thinking it has to be the wiring from the factory? either way I figure to but a battery disconnect on the truck.(to eliminate any fathrom voltage) Unfortunately haven't figured out how to do as this truck battery connector is different. Its not just a regular round bat connector but a round one with 2 connections on it.

Based on what you said, the controller is disconnected now? If so, is there any chance the brake pin is still energized? That could indicate a shorted wire. This stumps me. I have been around campers and stock trailers my whole life and can't remember one draining the battery after it was disconnected.

[Larry-NC]

Originally Posted by Folson

Hello 2x I have had this issue. Hook up the RV and arrive, disconnect etc. 3 days later go to start truck Dead battery. Jump the truck ,hook up go home disconnect park RV . Again I thought the battery or the kids left something on. But when this happened the first time went ahead and changed the Battery (bat was 4 years old) Now same exact situation 1 year later. Also this is 2 different RV' trailers. Checked voltages on the Truck conn. Found at the 1:00 position 12V and 13V at the 5. The 1 is the Batt Charge I believe but the 5 is the Brake controller. All the other positions 0. My question: is the Brake Cont. position on the connector, suppose to have voltage all the time ? or only when the brakes are applied. What's even more puzzling is that after the truck is jumped, RV towed, parked disconnected I can park my truck and use normally even after several days and no issues. Almost seems that the controller is somehow intermittent causing a battery drain? The truck conn ? or perhaps the truck wiring itself? The controller led is not on when the Trailer is not connected.

This can take some time, but here is how you can find the cause of a parasitic drain.

First, you have to be able to understand and reproduce the problem reliably, so you don't start chasing ghosts. You seem to believe that (a) the problem does NOT occur when you simply drive the truck and park it and (b) the problem does occur when you connect the trailer, drive, park the truck and disconnect the trailer.

First test as follows:

1. Disconnect negative battery terminal.
2. Set your multimeter to the 10Amp setting.
3. Plug black lead into COMmon jack and red lead into 10Amp jack (not V-Ω-A).
4. Turn the meter on.
5. Using a clip lead, connect the negative battery cable to one meter probe.
6. Connect the negative battery terminal to the other probe. (If you have a side-terminal battery, use one of these to help make the connection.

When you make the connection, the meter should briefly show current drain of around 5 amps as all the truck's computers wake up. As each one goes back to sleep the current will drop in steps. It should finally stabilize at about 10mA, which will show up as 0.010 Amp on the meter. My GMC takes about 20 minutes for this. Take note of the time as you will need it in subsequent steps. And remember the current, since this is the value you want to see after each test. (If the value is a lot higher--e.g., 100 mA--you have a parasitic drain all the time--it's just more obvious when the truck is not driven for 3-4 days.)

What we need to do now is test with the trailer connected, engine on, brakes applied a few times, engine off, trailer disconnected, to see if the final current is different. But obviously you can't run starting current through that tiny meter.

1. Disconnect the negative battery terminal.
2. Use an automotive jumper cable to connect between the negative battery terminal and the negative battery cable.
3. Connect the trailer.
4. Start the engine.
5. Shift to Drive.
6. Depress the brakes a few times.
7. Shut off the engine.
8. Disconnect the trailer umbilical.
9. Connect the multimeter without disturbing the jumper cable, so power to the truck is continuous.
10. Now disconnect the jumper cable and the multimeter should show the drain current. Wait for it to stabilize. Is it the same as the no-trailer test?

Write back if you do find current over about 10mA (0.010 Amp) and I'll provide hints about how to find the parasitic drain.

[Folson]

Hello great info and help. As we are in the process of moving and the trailer right now is in storage for a couple of weeks so I cannot work on. As far as what is happening I agree never have seen something like this. Larry great instructions and as soon as I can I will perform and let everyone know. Thanks again guys!

[Larry-NC]

Originally Posted by Folson

Hello great info and help. As we are in the process of moving and the trailer right now is in storage for a couple of weeks so I cannot work on. As far as what is happening I agree never have seen something like this. Larry great instructions and as soon as I can I will perform and let everyone know. Thanks again guys!

Just one afterthought that occurred to me late last night.

Even though you were probably driving to the campsite in daylight, is it possible that you had the truck lights on to power a rear-view camera? Is it possible that you left the lights on after disconnecting?

I know this is a beginner's error--just wanted to save you from a lot of work if this were the cause.

[n1acguy]

Originally Posted by Folson

Hello great info and help. As we are in the process of moving and the trailer right now is in storage for a couple of weeks so I cannot work on. As far as what is happening I agree never have seen something like this. Larry great instructions and as soon as I can I will perform and let everyone know. Thanks again guys!

From what has been posted so far, I suspect you have a short in the harness on the truck. I would look for visible damage under the truck. Something might have kicked up from the road and partially chopped the harness. Or a critter got to chewing.


I suspect the reason your brakes aren't applied or dragging continually is because the short won't carry enough current to do that, but it's still enough to drain the battery. Still not sure why this causes a drain without the trailer hooked up, but I'm thinking it's just shorted line to line and not to ground, so it doesn't blow a fuse.

It seems that based on what you did replacing the controller, you eliminated everything on the truck as the cause, except the wiring harness to the seven pin connector. This is assuming that the brake light switch isn't sticking, but you didn't mention any lights on.
When you measure voltage on the brake line (that shouldn't be there), you should start the truck without touching the brake (if it's not push to start) just to make sure the brake light switch isn't sticking when this is happening. That still wouldn't explain the drain with the truck off if the brake lights don't work without the engine running, but you definitely shouldn't have voltage to the brake line unless you're applying the brakes.
Just an idea based on your findings.

[Ohio_john]

Try replacing the brake controller relay under the hood..something is sticking on and energizing the brake pin wire. When you immediately drive it after unhooking, by depressing peddle several times it corrects itself. So..possibly brake switch down by peddle..or possibly sticking relay..

[Folson]

Ohio-John The Brake Relay and Switch is a great possability and not a expensive fix. Also checking the wiring harness completely is a good suggestion of course. But for sure everyone agrees no voltage should be on the Brake pin unless Brake is applied ? Thanks everyone with all this help I am sure I'll get it Ha! As soon as we get a little settled I am on it!

[Red Roadrunner]

Originally Posted by Folson

Hello I have this posted elsewhere but thought i'd try here also. My symptom is that for 2 years running when I disconnect the RV Trailer (18RR) after 3 days my battery is dead on the truck. This happened last year and figured a old battery but now its only 1 year. Anyway when I measure V the 1:00 pos has 12.7V but also the 5:00 pos (this is for the Brakes) From what I understand the 5:00 pos should not have V until the brake pedal is applied ? But in talking with a service tech basically stated no draw on the connector so it shouldn't matter. Anyway the V go away when I disconnect the Brake controller as it should on the 7 pin but the other pin still has 12.7 (1:00). Changed the controller same V readings.Chnged truck conn same V. When I disconnect the Controller and measure the connector from the truck 12v Blk 054Vred,white and blue 0 (truck off). When I depress the brake pedal 12V Blk,12V Red,0 white,0 Blue.(truck running) Is this a reversal coming from the truck? Isn't the Blue for Brake? Anyway on top of that after I park the rv at home and use the truck I can leave it sit for a week and no problem? It appears that it will battery drain if I let it sit after parking but after parking and then use within 24hrs the truck can sit with no issues? The service dealer suggested a battery disconnect to stop the fathrom drain? Very confused

Do you have daytime running lights turned on when this happens>? Check your dash, there is a small monitor in the middle of the dash near the windshield, make sure you have nothing covering it. We had this happen once. I had habit of tossing my hat upon the dash when traveling, never did it other times . It covered the sensor for the light and they stayed on after ignition was off, drained battery over night.