1990 Dash Wiring

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!

Nice work, much appreciated. Welcome! We should be able to print those off and use in our boat at the size they are at. Before posting any other picture you have to shrink it. I like using Microsoft Photo Editor to get them down to about 600X400 (just what I use, some may use other things/sizes)

Awesome! Good work.

BuffaloBFN wrote: My horn has an orange hot.

Load or supply side? My boat and drawing have orange on the load side and red supply.

^^Running a new ground could help things a lot.
I posted a thread with pictures about it here.

A new hot supply would be taking that a step further. When I added my ground, I left the original in place too.

Are any of your other gauges acting funny?

I have a '92 Sport and have had a few wierd glitches in my instruments. The alternator is putting out good voltage but my voltmeter only indicates 10 or so volts. Further, if I turn my navigation lights on (or any other high-load item), my voltmeter goes down further and my other engine guages (ie water temp and oil pressure) go UP. I cant tell you how many times over the last 10 years I have been motoring around our lake, as a family, at night time (with the lights on) and looked down to see my temp gauge reading something like 200+ ! DOH! Then I shut the lights off and it's all back to normal (170-180).

Okay, this forum is full of really smart people...any ideas?

BTW, what water temperature does everyone think is ideal running temp on your engines? (I've got the Pro Boss ProTec 5.8L). I know alot depends on thermostat, water temp, etc. but I've worked w/ Vince at DIM over the years and my boat just seems to be "stuck" on 180 even tho my thermostat is 160. Granted, the lake we boat on is rather shallow and quite warm (more like bath water) but any thoughts here too?

Minaqua, thanks for the diagrams and all the work that went into them---very helpful!   

I added another 10ga feed to my dash and I see 13.5 volts, but it drops to 12 with everything running, heater, bildge, stereo, Perfect Pass, blower and lights. Did you try it without the relay to see what kind of voltage you saw?   I know the stock wire is undersized, but I'm curious if your getting no voltage drop from the wire or the relay. My stereo is an iPod so I'm not sure it really has a draw once it's charged, the amps have their own battery and wiring so only draw they have from the dash is a turn on wire that also charges the iPod.

I ran a 10ga duplex wire from the protected side of the 50 amp breaker to the ignition breaker on the dash for the hot. For the ground I went from the battery connection to the block to the beginning of the birdsnest where the grounds begin to split at the dash, tied to the exiting ground a few inches before the split. A bus would have been better there, but I'm just to lazy to do that much wiring.

For Memorial Day Weekend I added 2 more deepcycle batteries for the stereo with a switch that feeds a second master switch and a voltage sensitive relay. Right now I'm chasing a draw that is killing the start battery, I think it's the relay searching for the other batteries when I turn them off. Anyway the idea is to be able to separate all the batteries from eachother. My idea is to be able to charge with a 3 bank charger and hopefully be able to replace individual batteries as needed since one won't be able to take out another.   Once I get it figured out I'll try towork up a diagram.

It's most likely overkill, we usually don't sit with the stereo on and always are able to plug in at the dock. There are a couple of times a year though where we might spend most of the day listening with a few hours of running. These times we won't have shore power to charge for 3 or 4 days. I just need to be sure on those days that I'm OK. Like everything else, I suspect the stereo will grow over time and make use of all the extra capacity I have right now.

The main switch is a little different, it turns 2 loads on but keeps them separate, the other switch uses on battery or the other or both., the VSR combines the main switch for charging.

A relay will not solve the problem of voltage drop due to under sized wire handling more loads than it should. However, a relay added to switch a higher amp load and removing that load from the ignition switch is sound practice but, the wiring and connections need work first.

Daveinater wrote: I have a '92 Sport and have had a few wierd glitches in my instruments. The alternator is putting out good voltage but my voltmeter only indicates 10 or so volts. Further, if I turn my navigation lights on (or any other high-load item), my voltmeter goes down further and my other engine guages (ie water temp and oil pressure) go UP. I cant tell you how many times over the last 10 years I have been motoring around our lake, as a family, at night time (with the lights on) and looked down to see my temp gauge reading something like 200+ ! DOH! Then I shut the lights off and it's all back to normal (170-180).

Dave, I had the same exact issues, but running a new ground, (I put details in a link in one of my posts above) solved a lot of that. Now my temp gauge holds steady when I turn on the lights etc.

I think the original poster, TX Foilhead, Pete and others are all correct and saying you should run a new hot line as well. TX's "duplex" idea kills too birds with one stone. You just have to be a little more careful with the hot, that it goes to the protected side of the big 50amp engine breaker, and to the constant side of the ignition switch. With the ground, you can run it to any "Crossroads" in the ground system and you're good.

Eric, great explanation. That helped a lot. Still trying to get some of this stuff.

I'm still not totally clear on the principle of the temp gauge and how it works electrically. Anyone?

Daveinater wrote: Perfect! Thanks and your post with photos was very helpful. Question: where do the ground wires come together behind the dash...is it under the dash pod or behind the switch panels? I ran a new ground and power to my stereo direct from the battery Perko switch in the back because I had a hard time figuring out the actual "source points" for power and ground behind the dash. I'd love to give a new ground and, if needed, power source for the dash instruments but am not sure where to route the ground to supply the whole instrument panel with a new ground source. I'm thinking this is the best way to go because just about every indication is affected by the activation of running lights. Further, as I mentioned, the Voltage Meter always indicates well below 12V even tho the alternator is putting out good voltage. We pilots hate guages that lie!!    I'll start with the ground first and see if I get any headway. Thanks again for the great post!

Probably not the same dash..but close..it gives you least and idea where to start...

brian´s 93 new dash ground cable with pictures

The ground at the dash was a bit difficult to find since it wasn't in a single place. If I remember correctly everything starts to split over on the breaker side of the dash. You can find the 10ga coming from the motor under the dash and just follow it up through the hole behind the speedos, then you'll hit the splits. I tied in right there, have a few large butt connectors, it took me a few tries to get 2 10ga wires together on one side while only having a single on the other and having to work in the mess of other wires.

Another thing, be sure to disconnect the battery, especially with the duplex wire. I'm lazy and don't always do that when I'm working on the wiring, I'll just turn off the ignition breaker usually. Everything on the motor is hot unless you have a battery switch or disconnect the battery.

Daveinater wrote: Thanks Sebastian...that's what I was looking at. Brian tapped in to the daisy chain that fed his perfect pass, depth finder, etc. but I'm thinking I need to route my new ground right to the actual ground source under the dash, or bus bar if there is one. (I will drop the panel under the dash because I cant get my fat head in the storage compartment door). I want to supply the entire dash with a new ground wire since everything seems affected by whatever the problem is. I need to find where the stock ground wire (that attaches to the engine) goes under the dash. The wiring diagrams supplied in this thread should be helpful, but are cut off so I'll have to look again.

Dave, the diagrams are cut off on my Mac, but my PC has a scroll bar. (score 1 pt for PC). Email me and I can send you the full size diagrams on Monday.   For the ground, the 10ga harness wire on mine goes into one side of a butt connector and about 6 - 16ga wires are crammed into the other side.

If you run a second hot, this would tie on the supply side of the ignition switch, same place the harness 10ga comes in. I did not find any distribution blocks on mine.

Def take off the panel or you won't be able to access the half the wires under the dash.

Daveinater wrote: Hey TX, clarify what you mean by "duplex wire". Did you just wire in a jumper parallel to the existing wire, to supplement it? What is the benefit to doing it that way vs. running an entirely new lead from the battery (or hot off the engine)? I have a "Perko" selector switch (OFF-BATT 1- BATT 2 - ALL) that cuts off all power from the battery so I am good to go there.

The duplex wire is a hot and ground wire in a single sleeve. Duplex wire Here