Cabin Lights causing stereo (acc) to turn off

[jroach]

I recently restored my 87 Sorrento 19'. I added a new stereo and touched a lot of wiring throughout the restoration process. When I have the stereo on and then turn on the cabin lights (which I have probably used 5 times over the life of the boat) the stereo turns off. Here is what I was planning on doing:

- Check the cabin lights to see if they work. Correct as needed

- Make certain that I have a good ground by checking the continuity between ground on the battery to the stereo and also the back of the dash. Correct if necessary

- Measure the voltage at the battery to see if the power drops when the cabin lights are on

Other thoughts appreciated.

 

[bahamabreisus]

How old is your battery, it sounds like a voltage drop when turning on the lights. Have the battery load tested, dont just check the voltage.

 

[Skybolt]

I would make sure that the cabin light(s) and the stereo are on separate breakers. If that is the case then as mentioned above the battery could be bad.

 

[jroach]

How old is your battery, it sounds like a voltage drop when turning on the lights. Have the battery load tested, dont just check the voltage.

Good question...Battery is about 3 y/o. It is an Optima Deep Cycle Marine.

 

[jroach]

I'll

I would make sure that the cabin light(s) and the stereo are on separate breakers. If that is the case then as mentioned above the battery could be bad.

I'll double check but I believe the stereo is on it's own fuse and the wire comes right from the battery.

 

[jroach]

Correction, power for the stereo doesn't come directly from the battery. The "Acc" CB powers the wiper, bilge and stereo switches (see pic below). @bahamabreisus might be right but not ready to exert the effort to remove the battery and take it to be tested

A little more testing revealed that:
- turning on the bilge didn't cause the stereo issue
- turning on the wiper DID cause the stereo to turn off. I know, sounding like a battery
- when turning up the stereo, it will turn off at a volume above x
- measuring volts the cockpit lights have less effect than bilge or wiper.

I think the stereo has two power sources (constant and switched). Need to check to see if that is wired correctly.

Also, futzing around with the CB for acc it broke. Might need to replace all of them as they are pretty brittle after 36 years.

 

[Skybolt]

Correction, power for the stereo doesn't come directly from the battery. The "Acc" CB powers the wiper, bilge and stereo switches (see pic below). @bahamabreisus might be right but not ready to exert the effort to remove the battery and take it to be tested

A little more testing revealed that:
- turning on the bilge didn't cause the stereo issue
- turning on the wiper DID cause the stereo to turn off. I know, sounding like a battery
- when turning up the stereo, it will turn off at a volume above x
- measuring volts the cockpit lights have less effect than bilge or wiper.

I think the stereo has two power sources (constant and switched). Need to check to see if that is wired correctly.

Also, futzing around with the CB for acc it broke. Might need to replace all of them as they are pretty brittle after 36 years.

The two power sources for the stereo is common. The one that is actually the stereo power source (constant?) should have a solid connection with a larger power wire then itself is.

But it does sound like the battery is bad.

 

[jroach]

Update:

- Checked the wiring on the stereo and its correct (constant power goes directly to the battery with its own fuse while the on/off power source comes from the acc switch)

- Wiggled the stereo wires, no change

- Wiggles the wires on the CB and it stopped!

On Digikey now but was thinking that all the CB's should be replaced.

- The CB I took out says 5A while the manual says 15A.
- The Acc CB is the only one labeled (see pic). I'm pretty certain these are the original CB's

Should I just stick with the manual specs?

 

[jroach]

@SKybolt

Thanks. I posted an update a few seconds ago, must have crossed in the ether. Thanks for your help.

 

[jroach]

Update:

Bypassed the CB and still has the problem

Off to have the battery tested (I deserve an "I told you so")

 

[Skybolt]

Update:

- Checked the wiring on the stereo and its correct (constant power goes directly to the battery with its own fuse while the on/off power source comes from the acc switch)

- Wiggled the stereo wires, no change

- Wiggles the wires on the CB and it stopped!

On Digikey now but was thinking that all the CB's should be replaced.

- The CB I took out says 5A while the manual says 15A
- The Acc CB is the only one labeled (see pic). I'm pretty certain these are the original CB's

Should I just stick with the manual specs?

While the CB's should be what is listed, if they don't pop then that is not your issue and the supply voltage/current is. That can mean a few things, bad ground, bad wire gauge going to the stereo etc. Could mean a bad battery as well.

Usually Stereos need there own CB and/or fuse with heavier gauge wire. Just for this purpose.

 

[jroach]

Good point on the CB. Just because of the boats age, should I consider replacing all of them?

Battery test attached. New battery on its way.

 

[Skybolt]

Good point on the CB. Just because of the boats age, should I consider replacing all of them?

Battery test attached. New battery on its way.

You should replace the ones that are not at the original spec first. If you really want to be proactive then, yes replace them all with new. Always better to be safe then sorry in this case.

 

[jroach]

I've replaced the battery and the CB but still have the problem. Seems like this all started after the restoration. I don't think that anything was removed (electrically) but something isn't right. I found another symptom or two:

- turning on the bilge doesn't cause the stereo issue
- turning on the wiper DID cause the stereo to turn off
- turning on the cabin lights causes the stereo to turn off but it goes back on (but no subwoofer)
- when turning up the stereo, it will turn off at a volume above x
- measuring volts the cockpit lights have less effect than bilge or wiper.
- fuel gage seems to be exhibiting strange behavior (“stereo on” the tank is full, same with cabin lights...I'll play around more with this and report back)

I'll also measure the "ground" again to make certain its healthy.

Any thoughts appreciated.

 

[Skybolt]

You need to have a large gauge wire (10 ga at least) feeding the 12v panel then from there properly sized wire for what is running per circuit. Also the ground wire(s) much match the feed gauge wire(s).

 

[jroach]

@SKybolt , roger that. I'll double ck but I believe that the wires from engine ground to the dash (don't really have a panel, just the CB's in the dash) are original and look to be 10 to 12g.

I can eliminate the stereo issue as it might be a speaker (or speaker wire) shorted.

I'll also take a video of what I'm seeing with the fuel gage...seems like the gage has always been a bit quirky in that I only trust its reading when the engine is stopped but key in the run position.

Thanks again

 

[jroach]

I’ve attached a pic of under the dash and while not all the wiring is 10g it looks sized well for the load. Thoughts?

 

[jroach]

I removed the cabin light bulbs (3 in total) one at a time. When I removed one bulb the problem went away. Moved the offending bulb to another socket and problem still happened. Can't imagine what is wrong with the bulb but it's a 12v Festoon style bulb. Any ideas how many watts? Maybe I should replace with LED?

 

[jroach]

Just in case somebody needs the info for later: Festoon Bulb, 12V 5W.

Also, I think that my radio issue is related to the draw of the three bulbs and the sensitivity of the newer electronics. The old AM/FM that use to be in the glove box had a wider band to operate within. Just speculation.

 

[Skybolt]

Just in case somebody needs the info for later: Festoon Bulb, 12V 5W.

Also, I think that my radio issue is related to the draw of the three bulbs and the sensitivity of the newer electronics. The old AM/FM that use to be in the glove box had a wider band to operate within. Just speculation.

The stereo needs to be on it's own power source. If there isn't room in the panel for that then go with something like below and wire directly to the battery. Not sure of any amps r the like that may be connected as well. But total up the fuses and go with an appropriate sized breaker switch. Go 10amps over the total.

https://www.amazon.com/RED-WOLF-Terminal-Connector-Electronic/dp/B09Z2PVMMZ/ref=sr_1_1_sspa?crid=214NBRCIZ2JU4&keywords=12v+breaker+switch&qid=1696364295&sprefix=12v+breakre%2Caps%2C204&sr=8-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&psc=1