Master Power Switch Problem on a Coral

[AlanW]

When I bought my Coral about 15 months ago, the Master Power switch on the dash woked just fine. The previous owner hardly ever used the boat and I suspect the cranking battery was usually low or discharged-I had to replace the voltage regulators in the motor a while back-probably from them being over-worked trying to constantly charge the weak battery when he did use the boat.

Since I have had it, I put a new Interstate 1000 amp cranking battery in it and keep it charged up. About 2 months after doing this, the master power switch quit turning off-it won't rock back to the "OFF" position-it stays in the "ON" position and the red light in it stays on. I got a used switch from the old Viper dealer here that the red light had quit working on. It took my original switch apart and basically the little plastic paddlewheel thingie inside that lets it rock back and forth between "ON" and "OFF" had melted. I put together one good switch out of the parts from both I had. It worked about 2-3 weeks before it did the same thing-it won't turn "OFF" and the red lights stays on. Now it is getting really gimpy and I am having trouble with keeping the switch in exactly the right little place where the other dash functions will work.

My new voltage regulators appear to being working correctly (200 EFI) and I don't see any high voltage readings, yet I appear to be melting the inside of this switch.

Donnie says a new switch from them would be $30 or higher and advised I could get something a lot cheaper. Besides, the original type doesn't appear to be up to the task.

Any ideas on what is happening? Anyone else have this problem?
Where can I get a switch that will work right and last?, etc....????
Thanks!

[hydro99]

Alan,

Your description of the failure gives a clue what to look for. Since the little "paddle wheel" looked melted, the current flowing through the switch created enough heat to do that. First, I would look for anything that is drawing excess current in the switched power circuit of the boat. Look for something that is "on" but not working or running, indicating a short circuit. Have you added any high draw accessories? What is the voltage reading from the switch positive to the negative ground circuit?

A second possibility is that the electrical contacts of the switch have corroded, creating a high resistance in the switch. That resistance will cause heat and the heat will cause higher resistance..... see where this is going? To check this, turn the switch on, turn on several accessories and take a voltage reading directly across the switch contacts. If you see much more than a fraction of a volt there is too much resistance.

Last, what year is your Coral? I have a '99 and may be able to look at my power switch as a reference for you.

[AlanW]

Thanks, hydro99!

Mine is a 2000 model Coral. Nothing on or in the switch looks corroded, the blades on the back where the wires connect look clean. All other accessories are turned off, all of them work properly when turned on, no circuit breakers on the CB panel are tripped, no fuses blown.

I have added one high draw accessory-a pair of 55 watt foglights, but they are powered from a trolling motor battery, not the cracking battery. There was a unused switch on the dash for Livewell Lights that my boat does not have. The switch was already wired with red hot power and the ground-I hooked up a wire from the empty blade on the back of that switch to energize a relay to turn the lights on & off from the dash. so I am energizing the relay with low amp dash power, but the lights and my stereo are powered by the trolling motor battery.
And the lights are only briefly used at night.

I am OK with testing for voltage, but my electrical knowledge is limited to pretty much the basics. However, everything else SEEMS to be in order.

I am wondering if I just need a master power switch rated for a bit higher amperage?

[hydro99]

Alan,

A wiring diagram would help here but that's probably not available. I would think that if the amperage rating of the switch was too low, then the factory would have had a big problem with replacements. Replacing your switch with one of a higher rating will not solve the problem if indeed one exists.

Do you have a voltmeter with an "Amp" setting? If so, you could disconnect the power wire from your switch and hook the meter up between the power wire and the switch terminal to take an amperage reading. Be sure to take the initial reading with the 10 amp scale. If the meter pegs on that scale you have a problem and it will need to be isolated.

A last resort would be to get a relay and wire the main power through the contacts, and energize the coil from the dash "Power " switch. That will take the load off of the switch and you can easily replace the relay if it fails.

John

[AlanW]

hydro99-thanks for telling me how to test. I have a multi-meter with the amp testing, and it has the 10 amp scale.

I am assuming you are speaking of the larger, thicker red wire on the back of the switch that should be incoming unprotected 12 volt power from the battery? (according to my boat wiring color code chart)

I didn't get a chance to work on this last night, but I will check it this weekend.
Thanks again for your help.

[hydro99]

Alan,

That is the wire. What you are trying to do here is measure how many amps are going through the switch. I would guess that it should be able to handle about 10 Amps or so if it is properly applied. The switch should also have a rating printed on the side, with a Voltage/Amp or Watt value. That will tell you what it is supposed to handle.

[AlanW]

OK, I'm back now-my work computer died Monday and I'm just now getting back up.

I tested with the multi-meter on the 10 amp setting. Remember the master power switch is broken/jammed in the "ON" position and the red indicator light is glowing.

I did the testing as described with the boat on the trailer and the engine off. With everything on the dash off, except of course the Master Power switch with the red light glowing, the meter read 0.08, which should be 8 hundredths of an amp flowing through it if I read the scale right.

I turned on the nav lights, depth finder, docking lights, and either the bilge or livewell pump, and the meter read 2.78 or something close to that, which should still be less than 3 amps, right?

Unless I'm reading the scale wrong, I don't see a problem with less than 3 amps flowing through it. I'm going to rig up the tester to the switch so I can take readings with the the boat on the water and the engine running at speed and turn on most of the accessories to make sure the amps don't go up with engine running.

Any other things I should try?
Thanks,

[hydro99]

With three amps flowing, your switch should be fine. I don't know what else to look for at this point unless there is an intermittent short somewhere.

[AlanW]

I haven't had a chance to test on the water with the engine running. I did do more testing in the garage on battery power. With EVERYTHING possible running at once, the reading was less than 7 amps, and that never really happens in normal use.

The switch itself is rated for 20 amps, so unless there is a big difference with the engine running, I seem to be a long way from over-amping the switch. Possibly the damage to the switch was done before I replaced the voltage regulators, when it was overcharging.

hydro99-thanks for you advise on this!