2800 SCR electrical issues

[Dantheman]

Hello, new member and owner here.

1998 Maxum 2800 SCR.
Few issues I’m dealing with. Horn, spot lights, fridge only works on shore power, alcohol electric range won’t turn on. Checked fuses found one that was blown that fixed the radio but can’t seem to run the rest of it down.

Theres also an 1800 watt inverter that looks like it on and running with a green light but receptacles are dead when not on shore power.

Motor 7.4 MPI runs great, shifts good but I did find a what looks like a vacuum line not hooked up back by the distributor and I couldn’t really find an easy place where it looked like it wanted to go might’ve been about 12 inches long. looks like it was connected to some other vacuum stuff right by the distributor.

Let me know if anyone has any ideas thank you!

Dan.

[mmwjr]

The inverter was not factory installed. Depending on how it was wired the receptacles may not be powered by it. The things that are not working are not related electrically and therefore need to be troubleshoot individually. Test to see if there is 12V at the horn when the button is pressed. No power check power at the switch, power at horn replace horn. Same process for the spot light. Does the range work on shore power? If not and the breaker is on check power at the heating element. Most likely the refrigerator has a power supply issue not working in DC mode. There should not be any vacuum lines on a marine engine, verify it’s tubing and not a wire.

[yahoo82]

The only relationship between shore power and the 12v system is usually the battery charger. It sounds like your house battery is disconnected but the charger is powering the 12v system when connected. Start investigating around the battery switches / battery connections. On my 2800 the battery switches were designed such that each switch belonged to a battery and both should be in position 1. Position 2 was the “jumper” position which allowed the battery to cross feed to another switch. I have another post on it. It seems strange but makes sense once you get it. These there often dealer wired so yours may be different.

[shrew]

Originally Posted by Dantheman

Horn, spot lights, fridge only works on shore power........Checked fuses found one that was blown that fixed the radio but can’t seem to run the rest of it down.

These are all 12VDC (Battery)

Originally Posted by Dantheman

alcohol electric range won’t turn on.

This is 120VC (and alcohol)

Originally Posted by Dantheman

Theres also an 1800 watt inverter that looks like it on and running with a green light but receptacles are dead when not on shore power.

This has a 12VDC input and a 120VAC output. 1800 watt models are typically not hard wired into the boat's 120VAC system. Instead they usually have a couple of outlets on them.

Usually the backside is the 12V and the outlets are on the front. plug something into and test it.

For 12V, start with the battery -> battery switch -> 12vac fuse bus IN -> 12VAC fuse bus OUT -> Each individual device.