Swim lights do not power on with switch.

drbeep

Hello, here I am with another electric related matter.
I have two underwater swim/transom LED lights. There were working until recent. I performed the following troubleshooting:
1. Checked power at the switch. 11.9V. Still no lights.
2. Checked power at the connector in the bilge. 11.9V. Still no lights.
3. Reseated the connectors on the fuse breaker.
4. Cut the cables to the LED lights and went directly to the battery, they work. Battery reads 12.6V.
5. Reconnected the cables and swapped the switch. No lights.

Has anyone seen anything similar to this?

Ian

Reverse polarity?

drbeep

Ian said:

Reverse polarity?

Nah. I checked that.

Grahamu

Sounds like you are reading surface voltage only at 11.9 volts. Check each terminal on fuse and switch or use a jumper cable around them.

drbeep

Grahamu said:

Sounds like you are reading surface voltage only at 11.9 volts. Check each terminal on fuse and switch or use a jumper cable around them.

Copy. Will do that.

drbeep

Quick update. I replaced the fuse/breaker and read 12.6 volts behind the switch. I then looked at the LED swim lights and they were faintly on. I checked power at the connection point in the bilge and now it read 6V. I swapped the breaker and jumpered the switch with the same results.
I'm at a loss as to what the issue could be.

MH342

It sounds like you may have a bad ground.  If you can get good voltage throughout a circuit but it’s still not functioning, it’s time to troubleshoot the return path.  When you check voltage at the leads in the bilge are you going from the positive lead for the light direct to the battery post, or some other point?  The best method is to check against a reliable zero-volt point … ideally the battery post. If you get any non-zero voltage when measuring between the ground lead at the light and the battery post, then you have a bad connection or voltage drop somewhere in the path back to the battery.