Back lights are dim
2021 fifth wheel, two 12V lead-acid batteries. On battery, converter off
Customer says: The bedroom lights are really dim. The kitchen lights are fine.
Tests you can run
- Battery voltage, lights on
- Voltage at a bedroom fixture, light on
- Drop on the positive side, battery + to fixture +
- Drop on the ground side, fixture – to battery –
- Swap a bulb from the kitchen
- Check the lighting fuse
Repair options
The lesson behind this case
Keep going on 12V and batteries
Learn it
- Volts, amps and ohms, the simple way
- Voltage drop: the test that finds bad grounds
- Practice: find the bad connection
- Batteries: lead-acid vs lithium
- Fuses, breakers and grounds
Prove it
- Battery dies even on shore power
- Lithium won't charge on cold mornings
- Coach is dead, battery is fine
- Batteries dead after storage
- Solar quit charging