The running lights have been pulsating on my 87 32’ with Chrysler 360’s
The battery was having trouble getting the port motor started and I was getting about 13.4 charge at the battery.
I cleaned all the connections with no improvement.
Looked for an external regulator to change but the previous owner has changed to alternators with internal regulators.
Took the alternator to the shop and had new bearings and regulator put in.
Back on the boat and the lights still pulse and the battery didn’t seem to charge. The battery could be bad but I am still wondering about the lights pulsating right in time with the alternator gauge needle?

Could this be a connection somewhere else?
Possibly still the alternator?

Thanks in advance for any help!
It was pretty hot yesterday on the Potomac for sure.
More time working on the boat than enjoying the boat so far.
Just bought her about a year and a few months ago.

Also I’m not new to the forum.
I couldn’t log on for some reason so I got a new password etc…
I was known as JB in the past

Thanks!

JB

I agree with Dave, I had a similar problem, all my stuff worked individually but when I tried to turn everything on, the lights dimed, sterio when down.....moral of this story: check your conections! Jack. PS my problem was too small a wire for all the things hooked to it on the neg. (unfused side) terminal (lucky the wire did not burn)and when too many items turned on the wire got hot and things did not work right.

Check the oil pressure switch. My nav lights pulsed while running from a defective oil switch.
A simple, reasonable fix from the auto store and some teflon tape will hopefully fix the problem or at least remove a variable.

-Karl

I'll have to look my setup to remember how I tested it. I'm going to head back to the boat this evening. I'll try to get an idea of what I did and post it asap.

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Ok.
The oil pressure switch is connected to the same feed as the oil sending unit for pressure gauges. On the Chrysler engines with the plastic cover at the back of the engines (usually log style manifold, pre 1987) the switch is just next to the starting solenoid. The 2 wires from the switch stick up and are connected with those crappy Chrysler brown Bakelite spade connectors. One 1 of the terminals I see 13.1V. The other terminal will be 0V as the switch is closed when engine is off. Once engine is on and pressure builds properly you should see the same voltage on both terminals. When I had pulsing lights, I was NOT seeing the same voltage on both terminals which, told me the switch was malfunctioning.
Remember 1 of the wires is hot all the time. If you remove it be sure it does not short to the engine block.

Take a reading on the hot side first and record that number. Put the meter probe on the other connector and have someone start the engine. You should see the voltage work up to the same value as the other terminal.
You can also jump the switch as you mentioned earlier.

-Karl