View Full Version : Nav lights = engine won't shut off?

05-16-2011, 07:41 PM
1991 Prostar 190, this problem just started happening. When the ignition key gets turned to on, the nav light on the bow comes on. The 3-position rocker switch (nav, off, anchor) is off and the illumination light on the switch is off. The engine runs fine. However, if you turn the nav light switch to on, the illumination light on the switch turns on, and while nothing changes as far as the engine running, if you turn the key off, the engine keeps on running normally. The engine will only shut off at that point if you flip the nav lights back to off.

Also, with the key off, when the nav light switch gets turned on, a couple of the engine guages come alive, as if the key was turned on.

Any ideas?

Brian B
05-16-2011, 11:22 PM
It's definitely a cross short.

Has any work been done behind your dash lately?

05-16-2011, 11:59 PM
Somehow the ignition key circuit is backfeeding through the navigation system. Start chasing wires to find the problem.

05-18-2011, 11:16 AM
Thanks guys. Brian B, to answer your question, there has not been any work done behind the dash lately.

This has been an awesome boat, I guess after 20 years a problem or 2 is bound to come up.

05-18-2011, 12:01 PM
Check all your fuses. If a fuse is blown you can get some strange back-feeds going on. It could also be a faulty ground somewhere that is causing the problem. I guess I would start with removing, cleaning and reinstalling the pos and neg at the battery, as well as the ground to the block...........then proceed to the testing the fuses.

I just had a hard to find problem with the remote start in my F150. Finally found a blade type fuse that had cracked internally giving an intermittent connection. It looked and tested fine both in and out of the vehicle. One time it didn't show power so I started looking closer and found it.:confused:

05-24-2011, 01:18 PM
Thanks, this boat has circuit breakers, all of 'em are not popped. Haven't had a chance to look into this yet on the boat, but I will post up as soon as I can.



06-07-2011, 01:34 PM
I pulled the dash apart last night:

The purple wire coming from the ignition switch goes straight up to the light (backlight for when the navs are on) on the fuel guage. On the positive side of the light, there is a bus bar with about 4 other wires going off of it (purple and blue wires). Everything there looks factory (and must be, my friend is the original owner). ...????

Here is where it gets more interesting:

The deadmans switch is right below the ignition switch and broke a few years ago. I bypassed it for him by cutting the wires (purple) going to the switch and joining them together (so the circuit is constantly connected). At the time I didn't think much of it and didn't check where the wires really go, just joined them together. Now I realize that the wire left now just goes from the ignition switch to the + side of the fuel guage light.

If you start the engine, then pull the purple wire off of the fuel guage (with the navs on OR off, doesn't matter), the engine will stall. I cannot connect that purple wire anywhere else and get the engine to run, it needs to be connected to the backlight on the fuel guage. So being connected to the fuel guage is completing some sort of circuit.

And again, other than bypassing the deadman switch, everything is stock. I followed the wires everywhere and they all look like new. (This boat has only seen lakes and always garaged and maintained.)

However, I have never seen a boat that still runs if the nav lights are on. This is weird!

06-10-2011, 01:07 AM
get yourself a new dead man's switch and see where that takes you!

06-19-2011, 09:53 PM
I'm having a similar problem on my 87 Prostar. The wiring was a mess (extra wires to nowhere, rats nests, etc.) so I was cleaning things up and got everything connected how I thought it was before I started. Then I noticed that the gauges were on with the key not turned on. I rewired some things and got the gauges to go on and off with the key. Engine started fine, then when I turn the key off, engine keeps running. To get the engine to shut off I had to pull the hot wire going to the gauges.

So, I think I ran a line to the battery where I didn't need one to get into this situation. I've been running searches looking for a decent wiring diagram of the dashboard connections, specifically the ignition. If anyone has one I would really appreciate it (or even what the wire colors mean).

As I recall, this ignition has three connections. One is yellow/red which goes to the starter. The other is yellow, I assume its the main power when the key is on. The other is red. I assumed this was just the 12V in from the battery, but I may be wrong because when I connected it to the battery I ended up in the above mentioned situation.

Any help would be greatly appreciated.

06-21-2011, 10:12 PM
So to help anyone else with this problem, I figured it out. So, boat keeps running after shut key off, engine won't stop. Had messed with wiring. This happens when the distributor cap is tied directly to the output of the alternator. Everything seems normal with the engine off. The gauges come on when the key is turned on. The engine starts fine, but when the key is shut off the engine keeps running.

Turns out I rewired the ignition and accidentally tied the battery to the wrong side AND moved the gauges and everything else that goes on with the key on to the other side. So, everything appears normal with no alternator power, but can't be shut off with the key.

So, to the original poster: Your Nav switch is tying hot from the alternator side to hot on the other side of the ignition. As a result once you have alternator power you'll have power on the part of the ignition that is normally switched out. My guess it they tied one end of the lights to the alternator side of the ignition and the other end to the switched on side. As a result the light is off when the key is on, but when you shut the key off enough current goes through the light to power everything on that side. So to fix it find the lead from the nav lights that is high with the boat off (the battery side) and move it to ground.

06-23-2011, 01:08 PM
Thanks for the tips.

Sounds like this is a slighly different problem - the guages come alive and ignition is hot once the nav switch is turned on, without the engine running (alternator is not charging), so somehow it is getting power from the battery.

Maybe it is the ignition switch that is allowing power from the nav lights (more specifically the guage lights) to backfeed into the ignition wire? And vice versa - if the key is on then the ignition power is able to backfeed into the nav lights?

Would anyone with a near vintage (this is a '91) boat be able to pull the ignition panel off and tell me where the purple wire from the ignition and deadmans switch go, or post a pic? Everything looks factory in this boat (besides the bypassed deadman's switch) but would be interested in hearing from anyone else how their setup is wired.

I don't think putting in a new deadmans switch would change things, as all it has is 1 wire in and 1 wire out, the switch is a simple on/off (closed/open). The original switch in this boat failed to off (open) so the engine wouldn't start. With the switch on, the wiring would effectively act like it does now. Thanks for the idea though Lars.

06-23-2011, 01:30 PM

I think the ground side of the lights connected to the nav switch is connected to the battery side power. (Or it may not be going through the light, it may be just through the nav switch). This puts a parallel connection across the ignition. The gauges come up with the nav switch turned on because it connects the battery side of the ignition to the side of the ignition where the gauges are. This will also cause the boat to keep running after the ignition is switched off because there is a parallel connection bypassing the ignition switch.

On my 87' the ignition has three wires. The yellow/red is the starter. The yellow comes from the battery and alternator. The remaining wire (I think originally purple) goes to all the gauges and powers the distributor cap. The dead man's switch should be wired in series with the purple wire.

To solve your issue you are going to have to find the lead from the nav lights and/or switch which is tied to the battery side of the ignition (yellow wire) and disconnect it. If its the ground side of the nav light move it to ground.

This is a little confusing, I can draw a schematic if you need it.

06-24-2011, 02:31 PM
I think I follow you, thanks for the reply. I will look into this. If ya got time, then feel free to throw up a schematic but no worries if not.

The weird thing about this though, is as far as I know this issue just started happening one day. (As if something broke/shorted as compared to being wrongly rigged.) A stereo shop did install a new deck, sub and amp in this boat so maybe they did something, although it doesn't look like they went into the dash wiring.

06-26-2011, 10:58 AM
WAC--I had this happen to me yesterday while I was out. Everything started out fine. Boat started, ran, and shut off just like normal. I was going to take a ride with my wife driving. When she started the boat she said the engine made a "snapping" sound (her description) and the boat sounded louder than normal at idle. I didn't hear any of this as I was behind the boat. When I stopped riding, the boat would not shut off. Gauges are still operating as normal (go off when key is off, etc) the boat just won't die. ????

06-28-2011, 12:50 PM
It could have been "dieseling (http://en.wikipedia.org/wiki/Dieseling)".

07-05-2011, 05:59 PM
WAC--I had this happen to me yesterday while I was out. Everything started out fine. Boat started, ran, and shut off just like normal. I was going to take a ride with my wife driving. When she started the boat she said the engine made a "snapping" sound (her description) and the boat sounded louder than normal at idle. I didn't hear any of this as I was behind the boat. When I stopped riding, the boat would not shut off. Gauges are still operating as normal (go off when key is off, etc) the boat just won't die. ????

To follow up on this post--my problem is now solved. Issue was evidently caused by a bad solenoid. Replaced it and now the gremlin is gone.

Probably gonna have to replace my starter now. I think when the solenoid failed, it caused the starter to remain engaged causing damage to it. I'm not for sure the starter is damaged but it sounds like total dog sh** now......