Blowing fuses

[Robbabob]

95 Chris Craft 21C, VP 5.0Fi
Dry dock at Chickamauga Marina, Chattanooga
Looks great, runs great! with the exception of some wiring issues

Boat is new to us, and trying to figure an apparent wiring problem and hoping to find enough hints to cut down my debug time.

#1 When we test drove the boat, there was no water in the bilge so no way to test the pump (blah). Come to realize the fuse was not even in the slot. When I put a fuse in, there is a "hum" coming from the bilge pump location (under the engine) without the bilge switch even turned on. Only way to stop the sound is to remove the fuse again. Previous owner says, 'might just be the "automatic float is stuck in the up or on position causing it to stay on.' Will put the boat up on maintenance stand tomorrow and see if the pump actually works. Not something I want to test while IN the water.

#2 Looking at all the fuses, the courtesy fuse was blown. Put a new one in and pop it goes. During test ride, we wanted to turn on the cuddy light.... 'oh, we had to use that bulb for the anchor light.' So, not knowing enough about boats yet, I will assume the courtesy switch allows juice to the light in the cuddy and something is shorted. Previous owners say they never had an issue with blown fuses.

I've already said to myself... "why didn't we just make them show us everything operational?!?!?" We could have ran or known what needed fixed.

Oh yeah, #3 I found a red bulb hanging under the dash by its wires (connector). No apparent place to be connected. Perhaps this was pulled out from the cuddy cabin light while they tried to fix the courtesy light circuit in #2.

Your help with these will be greatly appreciated!

 

[Rocky_Road]

Re: Blowing fuses

As for the red bulb, I would be looking at the backs of all of the gauges for a hole that needed it. The only red colored bulb that I can think of would be a gauge light (red doesn't impair night vision)!

Happy boating!

 

[Robbabob]

Re: Blowing fuses

Yeah, I did a once over but didn't find an open hole. Must be it goes into an upper gauge.


Thanks for the input. I'll confirm the other gauges have the same color bulb.

 

[Robbabob]

Re: Blowing fuses

Follow up:

The hum noise was one of the bilge pumps. We were fortunate the maintenance guy was willing to "climbed in" where I couldn't fit. He lifted the float and the noise stopped. I asked if it was wired backwards but he said the arm needed to be replaced.

I found the light bulb connects to the compass on top of dash.

Still no idea what is causing the courtesy circuit to blow the fuses.

 

[Rocky_Road]

Re: Blowing fuses

Follow up:

The hum noise was one of the bilge pumps. We were fortunate the maintenance guy was willing to "climbed in" where I couldn't fit. He lifted the float and the noise stopped. I asked if it was wired backwards but he said the arm needed to be replaced.

I found the light bulb connects to the compass on top of dash.

Still no idea what is causing the courtesy circuit to blow the fuses.

If you have more than one light fixture on the courtesy circuit, you can try starting with all the fixtures without bulbs, and placing a good bulb in each fixture one at a time...flip the switch on each time you add another bulb...until the fuse blows again. This would at least isolate the problem to one fixture. From there you can decide to go to the trouble of tracing the offending wires, or leaving the one bulb out.

Happy boating!

 

[stylesabu]

Re: Blowing fuses

and you could also try removing all bulbs and see if it still blows fuses. also you might want to invest in a curcuit breaker. as fuses get expensive after a while. never use a curcuit breaker to replace a fuse and think its fixed, a breaker can melt wires and cause much bigger problems if left in place in wrong application. I'm just saying use c/breaker for trouble shooting purposes.keep us posted, you will find the problem.

 

[Robbabob]

Re: Blowing fuses

ah, never thought it could be a fixture WITH a bulb... I really have no clue with this. i will review all the fixtures and go from there.

One idea I have is the utility outlet (aka car cell phone plug). I do not know if it is on this circuit, but the prevous owners may have fried it and now everything here could be shorted through it.

I may have a chance to review these this Saturday.

Thanks

 

[wire2]

Re: Blowing fuses

One other method to find a heavy load (short) is clip jumpers on to a car headlight bulb, place the other end of the jumpers on the 2 fuse connections.

The bulb will light while a short is in the circuit, allowing you to experiment. When the bulb goes out, you've found the short.

The headlight bulb will be in series with the short, so you won't fry anything.

 

[Robbabob]

Re: Blowing fuses

Alright. This is really starting to feel like real work. LOL

Tracked down 2 courtesy lights and removed the bulbs... still blowing the fuse. From what I'm reading in your posts, there must be more than the 2 courtesy lights I found. It's a bit confusing to understand how a bulb in place would creat the load to blow a fuse but removing the bulb alleviates the short. To me, a wiring problem at a fixture would exist with or without a bulb. I will continue to search as you suggest and clear my mind of its logic.

I can only assume there is another fixture (or two) I have still to find. Without an owners manual, I will post to try and find out how many fixtures will be on this circuit.

Thanks again!
Robb