Tiffin Starting/Running Problems

[TomBigFoot]

1. Dead Chassis Battery - reading at 5.1 V, no dash lights when the key is turned on. Dash lights would come on when depressing the Aux-assist switch (house battery assistance).

2. Trickle/3 Amp charger used with no success (raised to 5.7 V after several days)

3. Bought NOCO GBX155 (4000 Amp) jumper. When attached, still no dash lights.

4. When we used the NOCO jumper along with the Aux-assist switch (house battery), we were able to start the engine. Engine would not stay running unless the Aux- assist switch was being held.

5. While running, we were getting 13.3 volts at the chassis batteries (alternator seems OK). When we released the Aux-assist switch and the engine died.

6. The resting voltage of the battery is currently at 12.7 V. Engine will not start and run without the Aux-assist.

Any suggestions?

[dons2346]

Bad battery

[153stars]

How long did it sit before battery went that flat, could have issue with alternator.

[TomBigFoot]

It sat for maybe a week and then started. It sat for about two more weeks and the batteries were at 5.1 Volts.

Update: I just got back from the RV. I found that the voltage from the negative post to the “IN” side of the master switch is 12.7 as it should be. But the voltage from the negative post to the “OUT” side of the master switch is 0.0 whether the switch is on or off. I connect my NOCO jumper to the negative post and the positive to the “OUT” side of the master switch (thereby bypassing the master switch), the RV’s dash lights all came on. It looks like the master switch for the chassis batteries is an open circuit even when turned "ON". I am going to replace the master switch. Now I need to figure out how to replace it.

[BobGed]

You might want to check for a blown 200 amp fuse.

[TomBigFoot]

Update2: I replaced the master switch and everything works.

Thanks Everyone!