Depth gauge hot to the touch

[walterlaughlin]

So after a fun weekend of boating, we were headed back the marina and I go to switch off the depth gauge, and I notice the switch is hot to the touch. I touched the other switches on the panel and they did not seem nearly as hot.

The boat is a 95 Maristar 200VRS, I had the depth gauge installed by a prof mechanic, he wired it so it is powered on by one of the ACC switches. It seemed to be working fine the 4 times we have taken the boat out since the gauge was installed. I'm guessing it is probably a loose ground but would appreciate the forum's collective thoughts on the subject. Thanks

[east tx skier]

Don't touch it.



Sorry.

Bumping your post for someone wiser.

[Snipe]

My starter switch was hot to the touch on another boat. Turned out to be a bad connection (bad ground) behind the switch. Cleaned it up and....VOILA. Cool.

[walterlaughlin]

Bump for some help... Took off the dash panel, removed leads from ACC1 switch, squeezed on some dielectric grease, reassembled, tested -still getting hot. Switched leads to go to ACC2 switch to see if the ACC1 switch is bad. Tested -ACC2 switch now getting hot. Went under dash panel and found ground wire for depth gauge, re-crimped wire and tested -still getting hot. Not sure where to look next- fusebox maybe? Not sure where the fusebox is, not sure where the depth gauge taps into power source. Help would be greatly appreciated!

[walterlaughlin]

Bump for help! Thanks guys

[FrankSchwab]

If the switch is getting hot, there's a couple of possibilities left:
1. a lot of current flowing through it. These are probably rated at 10-30A, so it would have to be a LOT of current. If you have a digital voltmeter with a current measurement capability, measure the amount of current through the switch.
2. Perhaps it's just the light bulb in the switch. Mine has a small bulb inside the switch that illuminates when the switch is "ON". Try removing the bulb and seeing if the switch still gets hot, or turn on the OTHER ACC switch (with nothing connected) and see if it gets hot.

[walterlaughlin]

Re: #2, I turned on the depth gauge switch, the other ACC switch with nothing attached to it, and the NAV light switch, all at the same time. Then waited a few mins. Only the depth gauge got hot. All 3 switches have the little light bulb.

Re: #1, I'll get a multimeter to measure the current through that switch. Guessing the depth gauge would only draw a couple amps so I have no idea why there would be 10-30a running through that circuit

[FrankSchwab]

The depth gauge should have way less than an amp running through it - this document suggests 0.060 amps for a modern Humminbird gauge.

Another thought when you have the multimeter out is to measure the voltage drop across the switch. It should be way less than a volt, and combined with the current will tell you how much power is getting dissipated in the switch (p=current * voltage).