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BigEvi · 08-11-2021, 01:44 PM

Hi guys and gals,

I have some gremlins in my 2006 Fleetwood Discovery 39s, Freightliner XC Chassis, Cat C7, Allison 3000 trans.

I think these things may all be related but it is possible I have multiple problems that were intermittent before...becoming now more problematic.

Problem 1 - driving down the interstate when I hit sharp edged bumps/transitions the entire dash, all instruments, goes dark for a second and reboots and comes back on like nothing happened.

Problem 2 - sometimes, also when hitting a sharp bump ONLY the tach and speedo go to zero, the transmission downshifts one gear and the trans controller shows double XXs in the window...but just for a second while it reboots and goes back to normal.

#2 sometimes happens simultaneously with #1 but not always...sometimes just one or the other will happen. But reasonably certain these two are related.

Problem 3 - my chassis batteries seem to be isolated from the coach in every way. It seems as though the house batteries are doing everything, even engine starting. Like the chassis batteries aren't even there. Maybe I have an isolator welded shut in the BCC? I did notice the chassis batteries are swollen like they're bad...a month ago they weren't this way. Don't think they're too old...maybe 5 years. (Volt meter didn't make it back into coach so until I get to my dad's I won't know what they're doing voltage wise)

I sure hope there is a guru that can help me with at least a starting point on the LBCU...where to jiggle wiring...where to look for a bad ground...where to look for anything because I'm not sure where to start.

Thanks in advance, all!

-Eric

Tha_Rooster · 08-11-2021, 02:43 PM

What you say sounds like a loose wire.
If chassis batteries are bad the house batteries could be doing all the work, but what think “it’s not like they are there”?
What makes you think batteries are only 5 years old which they still could be bad and cause problems.

BigEvi · 08-11-2021, 04:52 PM

Quote:

Originally Posted by Tha_Rooster

What you say sounds like a loose wire.
If chassis batteries are bad the house batteries could be doing all the work, but what think “it’s not like they are there”?
What makes you think batteries are only 5 years old which they still could be bad and cause problems.

Always appreciate your replies.

Before these problems when driving the LBCU would show chassis batt voltage around 13.8v. And at same time while driving but also running the gen the house batts charged at around 14.5v. Now while driving the LBCU and the house batt voltage is almost always identical...the LBCU is only 2 tenths of a Volt lower than the house Volt meter. This is why it seems like the chassis batts aren't doing anything...and possibly there is a relay or isolator solenoid that isn't switching to the correct position.

I'm thinking the isolator isn't isolating the chassis batts and my charger is burning them up...maybe. I now have a DVM...headed out to probe some batts and see what the heck is going on.

-E

BigEvi · 08-11-2021, 05:13 PM

Another update.

Coach parked. Generator running. Tried turning off the chassis batteries at the switch on the inside panel (had wife do it while I was at the batts with DVM). The batts never changed voltage. The relay was making a very nice positive sound but with zero effect.

I pulled the battery disconnect fuse, relay made same satisfying sound. Chassis batts now read 6.5v and less than 1v on the other! I pretty much knew they were toast due to the swelling. But I didn't think that far gone! This is probably what's causing my LBCU problem as well...thoughts?

-E

BigEvi · 08-13-2021, 08:35 AM

Found the problem...or at least a problem. I hooked up 2 new batteries and a fire immediately erupted in front of me until the negative lug melted itself out of the battery before I could get it unbolted.

Positive cable insulation damaged and grounding out the whole system. Have it tapped up for now until I can replace it.

-E