Lance camper draining battery

The readings on the truck batteries won't be 0. The truck uses some power to maintain the computers even in sleep mode. What you should be looking for is a significant increase in Amps with the camper plugged in.

I talked to my work and there is a DC clamp meter I can bring home to try troubleshooting this. I wont be home until mid next week so I can put a plan together on things to test.

- Clamp the positive and negative lead on both truck batteries with the camper plugged in and unplugged. Ideally both readings should be 0.

- Clamp each wire on the 6 pin wiring harness on the truck side while plugged in and unplugged. Even both 8 gauge + and - wires.

Any other suggestions on what I should try to use the DC amp clamp on? Or something else I should try doing to solve this problem?

Thanks for the help guys

Desperate times call for desperate measures: It might behoove you to build a "breakout harness" so you can measure Amps on each individual wire coming out of of the 7-pin plug, WHILE it is plugged into the camper.

For this you need a male and female 7-pin, a bunch of wire, and a piece of plastic like a cutting board and 14 sheet metal screws. Arrange the screws in two parallel rows of 7. Connect the 7 pins from the male plug to one row, and the 7 pins from the female plug to the corresponding screws in the other row.

Now you can jumper across to connect each function, or touch the two corresponding screws with a meter set on Amps to see how much current is flowing. Current should NOT be flowing.

Don't assume anything. Do all seven pins.

I believe there are assumptions being made here which are causing the real issue to be overlooked.

joerg68 wrote:
What should backfeed there? All pins used for lighting have 0V when the truck is parked and everything is off. And the +12V line is not connected.

The computer not going to sleep for whatever reason might be a good theory. Incidentally, that would explain what happened with my own Silverado.

I'd still try to measure the base current with and without the camper plugged in.

The backfeed would require a problem with the wiring harness in the camper. Somehow a stray voltage getting applied to one of the lamp leads feeding back into the truck from the camper's battery. A long shot probably not worth pursuing.

Another place to measure current would be the ground lead of the plug. If current is returning to the truck through there then that's a sure sign that the 12v is getting there somehow. Only problem there is the 8ga line bolted to the chassis is an alternative ground path. Maybe check current on the ground leg with and without that 8ga wire connected?

What should backfeed there? All pins used for lighting have 0V when the truck is parked and everything is off. And the +12V line is not connected.

The computer not going to sleep for whatever reason might be a good theory. Incidentally, that would explain what happened with my own Silverado.

I'd still try to measure the base current with and without the camper plugged in.

paul_arc wrote:
Can it be anything with the 8 gauge ground wire that I have bolted to the truck chassis but I don't have the 8 gauge hot wire to the batteries? I was just figuring the ground needed to be hooked up in order to make the turn signals and brake lights to work.

That shouldn't matter. The ground for the signal lights is normally picked up from the ground line on the trailer plug. The line you added should just be in parallel with that, basically providing lower resistance to the battery negative, but other than that...

AnEv942 wrote:
The backfeed sounds plausible though don't know how that would work-being on light circuits wouldn't think they could trigger truck, even less how power could be trickling back on light wires of camper other than something looking for ground?

Yeah, that was really a reach. I was thinking along the lines of a computer seeing odd signals on an input could prevent it from going into sleep mode. Not sure if that truck has a turn signal module or are the blinkers and associated bulb tests handled by computer. Like I said, a reach.

I really am scratching my head on this one, curious showing no 12v on the trucks 7 pin. I was leaning toward the Y harness being the fault as Ive' read not uncommon for them to end up with wires mirrored. Now I'm wondering if indeed the factory charge wire is connected in truck.
Doesnt really have much to do with issue though, except How or by what path is camper draining truck.

The backfeed sounds plausible though don't know how that would work-being on light circuits wouldn't think they could trigger truck, even less how power could be trickling back on light wires of camper other than something looking for ground?

Measuring the amp load on truck battery a good idea to see overall what is being drawn with/without camper connected. Nothing on- door closed should be under an amp, when checking with camper on make sure everything is off. I dont know what a normal parasitic load of camper could be (in theory zero)- but for it to draw truck down in a couple of days I would think at least an additional amp.
I gather you may have an additional fuse block on umbilical connection according to the manual pg49 ,90
https://www.lancecamper.com/download.php?f=Lance-Truck-Camper-Owners-Manual-2016.pdf
If so you could measure load/amp draw for each circuit
and or errant 12v coming out of camper.
I agree looking for the weird at this point-as it seems the obvious isnt...

I don't have anything extra plugged into the truck when the camper is plugged in. Just the camper plug. I thought maybe the brake controller but it is always in the truck and I didn't tap onto the output wire for the brake controller.
I checked the voltage on the lance plug and I have 13v on the charging wire that is coming from the camper battery and isolator. but on the truck side, that wire is just capped off under the truck.

Can it be anything with the 8 gauge ground wire that I have bolted to the truck chassis but I don't have the 8 gauge hot wire to the batteries? I was just figuring the ground needed to be hooked up in order to make the turn signals and brake lights to work.

This is a tough one. I'm starting to wonder if it's actually the camper, or something else you use while the camper is loaded. Do you have a backup camera or anything you plug in inside the truck that you only have hooked up with the camper loaded? You did say with the camper unplugged you don't have this problem. Was that with no other changes than the camper plugged pulled or was that with the camper unloaded and maybe something else also disconnected in the cab?

The truck's computers are supposed to go into a low power mode sometime after shutdown. But I have a bluetooth OBD-II reader that apparently keeps mine active and will kill the batteries in a few days if I forget and leave it plugged in.

Not sure if/how this could happen, but check if you have any stray voltages on the camper side of your plug. Maybe a stray voltage being back fed into the truck is keeping some electronics from going into low power mode?

Just throwing out ideas, just in case. You've covered the obvious stuff. Now it's time to look for the weird. :)

I would think that would mean that it shouldn't be able to drain the truck battery??

I am no electrical engineer, but that would be my expectation as well.

My Silverado used to drain the truck battery on its own... you could barely park it for 2 weeks. In the 8 years I had it, it went through 4 batteries. The reason was never found (we suspected it might have something to do with OnStar and the fact that the truck was here in Europe, forever unable to talk to its mother back home in the US). But you say all is fine when the camper is not connected.

If you disconnect the battery ground wire, (and leave everything turned off), you should be able to measure the current with and without the camper plugged in. There should be a significant difference. Otherwise you are hunting a ghost.

Of course the computers will need to relearn after you reconnect the battery...