1990 Dash Wiring

MinaquaWI wrote: In an effort to be a contributor to the site, I wanted to share my most recent project with the group in case any of you would find it useful or interesting. If anyone would like larger bmp's of my wiring diagrams, please let me know. This year we bought a 1990 Sport Nautique and on the first voyage learned it has quite an annoying chirp and less than 10v from the common "low-voltage/bad ground/corroded connections at the dash" condition that I've been reading about. After spending an hour under the dash with a multi-meter tracing wires I put together a wiring diagram based off some of the other diagrams on this site. Right away I noticed a few things that didn't seem correct, so I also made a diagram of what I believe the wiring was from the factory. I have not verified EVERY wire but believe this my diagram to be pretty accurate. I would invite feedback on this from other members - specifically, what is the orange wire from my one accessory switch going to? It doesn't appear to power anything. And then lastly, I made a diagram of the changes I made to the boat. This includes running two 8ga wires to the dash, powering the ignition switch using a relay, adding two power points (which is really how this whole thing started) and providing new grounds to some equipment. I did not go through and clean the connections or solder anything. I am getting a solid 13.5 volts on the gauge while running and turning on accessories like the blower, heater, or stereo don't even make the needle move. Again, please provide input on the diagrams - I had to move some gauges and switches around to make it look like my 1990 dash so there may be some adjusting I need to do for wiring. If we can get the "factory" diagram to a point where the site admin's are comfortable, I would be happy to provide the larger sized file to be posted in the reference section. Thanks!

Keith,

Pete- I think there is something more to this than that, I think it’s the way PCM has it wired. The reason I think this is because my Shamrock does the exact same thing, all electronic’s shut down when starting. I have dual Optima batteries with a Perko switch, no matter what position the switch is in out they go , one, two or both. Never looked into it but I had planned to run a separate fused lead from the second battery just to feed the electronics. The only thing common between these two boat companies is the PCM power. Is it possible the solenoid shuts down power to the accessory side of the system when in the start position?

I just happen to have the Shamrock here at home for an engine change. Since Ken has raised the bar I will go out and throw a battery in it and test. It has done it with 2 new batteries and has done it when you crank it over with both supplying power. That's why I suspect PCM has wired it so it kills all accessories while in crank mode so that it does not lower voltage to the coil. Maybe that's why they don't bother to bypass the coil resistor when starting?

Gary,

Some people might do a Google search or find an electronics geek type to see what could be done to keep the radio on when starting the boat (or car)

That is a great idea! In my case I have installed a relay between the switch and radio where the relay is powered direct to the power block. In this case, where would the small 16v capacitor need to go?

drekeith wrote: That is a great idea! In my case I have installed a relay between the switch and radio where the relay is powered direct to the power block. In this case, where would the small 16v capacitor need to go?

I'd think I'd put the diode and the capacitor after the 87 terminal in that order to feed the radio ( relay to diode to capacitor to radio)