Chassis Disconnect Issue - Why?!?!?!

[jwilson32]

So we've been really enjoying our 02' Coachmen CC Elite MBS354 for the past few months. The kiddos have loved it and it sure beats tenting it! haha... My question is from an issue with the chassis disconnect that occurred last night when leaving the campground....

We set up camp around 8pm last Friday and broke camp last night around 7pm (3 day trip). We were connected to 50amp shore power the entire time. When I went to start the motor, it was dead. I tried using the button that uses power from the house batteries, but there wasn't enough there to turn the motor over. I looked at the chassis disconnect light which was really dim. I pushed the disconnect button a couple of times and it would shut off and turned back on, but still dim. Tried jumping with just one set of cables and no dice. Luckily my buddy had a diesel pickup with two batteries. We connected a second pair of jumper cables and she fired up. The problem is, the chassis disconnect light isn't on at all and I don't have any power to Wipers, Mirrors, Chair, AC or defrost fans. Everything else works such as gauges, shifter pad, lights, dash lights, etc. I checked all of the house breakers and fuses, all of the fuses located near the chassis batteries and the relay fuses as well. All were good. I also pulled the disconnect panel and found one glass fuse which was good.

I also want to mention that the system is charging as well. We pulled in last night around 2am and when I went to move it this morning, it fired right up. My wife had an electric cooler plugged into the 12v cigarette outlet on the dash. Could that have drained the batteries? If so, do they not charge when connected to shore power?

I cannot figure out where else to look or where to start? Any suggestions would be greatly appreciated. I'm not an electrician by any means, but can use a volt meter and would much rather spend my time looking for the issue than paying the dealer. Of course if that's the last resort, I guess it is what it is.

But I bet with y'alls help I can do it!

Please LMK if you need any other info...

[jwilson32]

I spoke with a guy at Forest River and he felt the issue is possibly with the battery (maybe a dead cell) and suggested that I have it looked at and replaced. If they are good or if I replace it and I'm still having an issue, he thought it might be the isolator solenoid for the emergency start switch. Only problem is, he doesn't know where it's located.

Anyone here by chance know where it could be?

[MEXICOWANDERER]

Some functions sould remain connected like the ECU and radio so they don't lose their mind when cut off from the trough. Doing a cold start at -20C can be a little unsettling if the computer must relearn to eat using a fork.

[jwilson32]

Hey MrWizard,

Yes, I have two disconnect switches... Actually it's a toggle switch. Pressing it to the right will disconnect the coach and to the right will disconnect the chassis batteries.

This is really weird... I was messing around with it today, and when the motor was running, I pressed the switch that supplies power from the coach batteries when the chassis batteries are low (I'm not sure what it's called) and of course, the chassis disconnect light came on. I had power to all of the items listed above that previously did not!... Unfortunately, that victory was short lived. When I turned the unit off and back on, I didn't have the same luck... That switch was the same one I was pressing when I tried starting the unit yesterday when it was dead. I looked under the dash and holy sheet, what a rats nest! I found another fuse panel although they were all good. I also found two large black boxes that had fuses, relay's etc in them. All of the fuses looked good, I'm not sure about the relay's...

So I'm still scratching my head. I'll clean all of the connectors tomorrow and see if that helps.

[MrWizard]

some body wired something wrong..
those items should be connected to the ignition run circuit, NOT the chassis disconnect relay

somebody some time got some wires wrong when repairing or replacing something

start with a chiltons book for that chassis, and trace those wires and move them to the right connections

it won't cover the RV side of the wiring, and it most likely will not show the chassis disconnect

but it will show wire numbers , size, color, code and where those wires for the wipers etc are supposed to be connected

most likely one BUSS wire 10~8ga that was moved from One terminal to the wrong one

Do you have (2) disconnect switches ? house and chassis ?

not all rvs disconnect the chassis, almost all can disconnect the HOUSE aka Coach

[jwilson32]

The "Why ?!?!?!" in the title is more of a why me? Not why are the batts dead?..... Maybe I should have phrased my question differently....

My chassis disconnect doesn't seem to be working properly. When I connect/disconnect it, it do doesn't seem to do anything. I can start the vehicle, drive it, etc in either position. What doesn't work are the windshield wipers, mirrors, defrost fans and drivers captains seat.

When I press the button, I can hear the relay although it's not making the connection somewhere. I'm just trying to figure out where to start and what to look for?

[MrWizard]

You answered your own question
Thermo electric coolers draw about 4 amps steady 24/7 as long as plugged in..yes that killed the battery

No the house converter does not charge the chassis batteries on all RVs , yes it does on some, but if you have the chassis disconnect in use...then it is not going to charge, even if it is wired to be able to charge