Without going into too much detail, I mounted a remote fuse block under the front hood with 8 different circuits powered by a main lug from the battery. Each is independently fused, various amps. From the fuse block, I can run whatever I want without concern of blowing a main in-line cart fuse.

Agree with all that the best approach is to use a relay as described. I will add that you might want to consider adding a marine fuse box in serial with the relay. They are very cheap to buy, and give you the ability to then independently add multiple additional fused circuits very easily. It will also allow you to clean up the rats nest tap in approach that many of us have on our carts. Coming from motorcycles, each of those tap in connectors is an opportunity for issues down the road. If I have to tap into a wire, I've had good luck with Positap connectors, or often splice/solder then liquid tape seal the connection.

There is one additional solution, albeit more expensive and overkill for most. They sell smart fuze boxes that can be wired directly to the battery, then a single wire to switched power --- no relay needed. The boxes then use a phone app to set up each port/connection, and you have full control of each circuit. This comes of value say if you wire in Christmas lights and want them to stay on for say 1 min after you switch cart off. Tons of flexibility, and can be very cleanly installed --- but often overkill. I've used the Neutrino smart box in the past, but there are several available.

Just a heads up, I don't know if applies to golf carts or not. I was told of this by a friend so I looked it up. Text of Florida Statute 316.3045

Operation of radios or other mechanical soundmaking devices or instruments in vehicles; exemptions.—

It is unlawful for any person operating or occupying a motor vehicle on a street or highway to operate or amplify the sound produced by a radio, tape player, or other mechanical soundmaking device or instrument from within the motor vehicle so that the sound is:
Plainly audible at a distance of 25 feet or more from the motor vehicle; or
Louder than necessary for the convenient hearing by persons inside the vehicle in areas adjoining churches, schools, or hospitals.
The provisions of this section shall not apply to any law enforcement motor vehicle equipped with any communication device necessary in the performance of law enforcement duties or to any emergency vehicle equipped with any communication device necessary in the performance of any emergency procedures.
The provisions of this section do not apply to motor vehicles used for business or political purposes, which in the normal course of conducting such business use soundmaking devices. The provisions of this subsection shall not be deemed to prevent local authorities, with respect to streets and highways under their jurisdiction and within the reasonable exercise of the police power, from regulating the time and manner in which such business may be operated.
The provisions of this section do not apply to the noise made by a horn or other warning device required or permitted by s. 316.271. The Department of Highway Safety and Motor Vehicles shall promulgate rules defining “plainly audible” and establish standards regarding how sound should be measured by law enforcement personnel who enforce the provisions of this section.
A violation of this section is a noncriminal traffic infraction, punishable as a nonmoving violation as provided in chapter 318.

What so I can’t play my Slayer albums? I mean they only allow volume 10 for Slayer albums. :D

That’s what I use; great sound and I have the ability to hide it from thieves.

Thanks for everyone's responses. I did end up going to Brownwood Village Golf Carts and they did sell me the brackets for $42.

My neighbor opened up his dash on both of his Yamahas (installed by Village Golf Carts) and they have this voltage regulator between the switched power and the speakers:

DC 5.5~32V to 1~27V 5A Buck Converter/Adjustable Voltage Regulator/Car Adapter/Power Supply Module/Driver Module

What would be the purpose of this? Just to make sure the voltage going into the speakers would be around 12 v without the spikes, etc? Doesn't seem like the speakers would be that sensitive since they're designed to be connected directly to a motorcycle battery.

Thanks, I did end up getting the brackets from Brownwood Village Golf Carts!

Here is my GUESS, some Yamahas have a problem with the voltage regulator that causes the battery to be overcharged and the voltage to go the 17+ volts, this regulator would stabilize the voltage to the speakers. IMHO, the fix should have been applied to the golf cart voltage regulator.