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Gages are Shorted Out

S

spectrum

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"PRELUDE: I have a boat that

"PRELUDE: I have a boat that none of the gages work. The purple wire seems to be the wire that gives each gage electricity for the lights and I guess, to power the senders? My problem is that the Purple Wire has a dead short. I am assuming that this may be the problem for the purple wire to spark and make everything go dead when I jumped a hot lead to it.
My 1989 Spectrum Series 1950 boat runs great except the gages and the gage lights do not work. Being anal about having gages that work ( Flying To Long!) made me start working trying to figure this one out. It should be simple, or so I thought! The fuel, oil, tach and water temp gages have three poles and it is like "Bakelite" (sp). They are shaped in a "V", to match the positions on the gages Of course the voltage gage just has just two wires the purple and ground. I checked the "Volt" gage, in case someone had placed the "V" backwards, automatically grounding the "hot" purple wire. I double checked to make sure the Purple line wasn't going to a dead short. There are two common wires, a purple one and the black, the ground and then the different color wires from the senders.
The starter switch is only a three pole type, (Red) battery, (Yellow with cross hatches) ignition and a "purple wire". The switch allows the purple and yellow with stripes wire to become "hot" when in the "run" setup. I used a jumper wire (positive) to jump it to the purple wire and it was a direct ground, and almost welded it together. I followed the bad purple wire back as I far as I could but I still couldn't find anything indicating a short. The bad (purple)wire was not wired into the under dash fuse bock, all of the fuses were all okay.
The wiring harness runs along the starboard side and has very few places that I could pull the wires apart enough to find the purple wires path to the engine. I wasn't able to find the same gage purple wire anywhere inside. At the engine the wires come out of the loom and I was able to find the purple wire. The wire disappeared again inside a closed harness. I cut the insulation away enough to be able to test the wire. After hooking the wires back up to the ignition switch and turned it to the "ON" position the purple wire in the engine compartment did show that it was hot. It was controlled by the ignition. I double checked the wire color coming out of each of the sensors and using a continuity tester it confirmed that the wires were in the proper connector under the dash.
Here is where I am now. If my memory is correct, voltage is sent to the senders (water, oil and gas,)and then the results are send back to the gage registering the water temp and oil pressure by the senders resistance? This just gave me a thought, should I have taken the senders out one at a time to see if there is one of the senders has fried itself and is grounding the sender out, thus making the purple wires under the dash shorting out?? This is pure crazy, but I have rewired several late model autos that had been in an electrical fires and the vehicles started and ran like nothing had happened, well, except for the sickening smell inside the car! This one has my brain cells shorted out. What the heck am I missing?
When I called my boat dealer he said that there is a meter now that will help track shorts. Has anyone used this type of meter before? I have drawn up a schematic if that would help. Its to big for uploading in here, but i could sure send it to you if it would help!!
Thanks in advance

Steve Hampton"
 
"I only read the first few sen

"I only read the first few sentences, but.

Unplug all gauges. Unplug anything easily unpluggable.

Put your voltmeter across the fuse holder terminals where the blown fuse is (take the fuse out)

Reconnect power - if there's a dead short, you'll read full 12V potential across the fuse holder.

Unplug and disconnect things one at a time until the voltage reading drops drastically.

When you see it drop off, you found the shorted component or circuit.

Instead of drawing your own schematic, consult the schematic for your engine.

The tool to check for shorts to ground is a voltmeter.

You can put the red lead on the B+ terminal of the key.

and then probe stuff with the black lead. If whatever you touch is at ground potential, the meter reads 12V

Keep the meter on Volts!, as There is no path for current to flow, and you won`t be arc welding under the dash.
Jumping around with a wire like that can start fires and burn up expensive gear.

This is why digital voltmeters rock.
You can stick the probes on anything you want and do no damage. They are just reading potential or electrical pressure between the 2 probes."
 
"Hy

Yeah, I have tried all

"Hy

Yeah, I have tried all of the unplugging. I have all of the wires off all of the gages. The fuses checked out okay because thats where I went to first.
I will try to figure out the volts that you are talking about. Everything is hot where it is supposed to be and nothing feeding back through when I re hook the battery up, no sparks. I am at a loss. Like I said in the main one I have been good at wiring since my first cars wires burned up.. Please keep 'em coming.

Thanks
Steve"
 
"Like Hy says...start unpluggi

"Like Hy says...start unplugging to eliminate, use these 2 links for the schematics

This one is for 1989 fords

http://www.selocmarine.com/content/manuals/3404/pdf/340410w152.pdf

This one shows the dash wiring

http://www.selocmarine.com/content/manuals/3404/pdf/340410w202.pdf

Your theory about the senders is a little off. The purple wire provides power to the gauge, the senders are in fact grounded and only have a single wire going to the gauge, the senders are providing the ground to make the gauge work, if you suspect a bad sender causing a short then simply remove the single wire plugged to it. If you really had a direct short to ground I would have suspected a blown fuse (didn't see that in your initial post unless I missed it?) Ultimately the power at the dash comes through 1 of the 50 amp fuses so if it went I think you would have seen some fireworks."
 
" a short to ground, with no f

" a short to ground, with no fuses blowing or breakers tripping....

Not possible without clouds of smoke and flaming puddles of liquid insulation."
 
"Hi Bob

Thanks so much for

"Hi Bob

Thanks so much for the pages. They are somewhat like I have in my manual. The "OMC Stern Drive"
I have printed the pages and I will see if I can follow where the purple wire goes to once it leaves the main harness back at the engine. To me that seems like it may be what I am needing.
I have unplugged all of the fuses, and again like I told Hy, none are blown. Every switch, Nav, blower, bilge pump, and both fishing well pumps are working just fine. Everything except the darn gages and lights. Pleeease don't give up on me, I will try everything. Oh, and I did have a person with electronics out here with a new digital type ohm meter testing everything and he gave up too.

Thanks for the responses
Steve"
 
"Is the purple wire attached t

"Is the purple wire attached to the ignition switch now and has it always been? Do your gauges actually have lights inside (some don't), these are usually connected with separate wires (both pwr and grnd). Is there any chance you can take a pic of the under side of the dash?"
 
"Bob
I don't know how I m

"Bob
I don't know how I missed the text under the links that you sent August 25, 2009 @ 10:55pm but I sure missed it. Sorry about that.

Thanks for explaining the senders, if I had it my way I would go back to the mechanical like I run on the race car. But the oil line would be to darn long to run and I only use copper to keep from chaffing.

Maybe this little story will help. About three years ago I completely stripped the boat and put new floors, carpet and upholstery in it. I was trying to keep the dash, steering and all of the wires together. I permanently marked each wire as I took them off and the identifications are still on the wires. While it was apart I remember seeing one main fuse, such as the 50 amp or an inline fuse. For the life of me I cannot find it now. Now is one of the several hundred thousand times I wish I had not broke my back in three places! I am going to go back under and if I have to I am going to start stripping the whole harness out from under the gunnels to see if I can find that breaker! The pictures will be in the very next post. MAybe I won't have to be under the dash to long after you see them.

Steve"
 
DARN! I am going to have to fi

DARN! I am going to have to figure out how to down size the pictures. I will not allow me to upload any of them now. I will get it done!!!
 
"<[img]"http://www.marineengin

"
292264.jpg

Dash of the Specrtum, in case it helps?"
 
"<[img]"http://www.marineengin

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292276.jpg
Another shot under the dash"">
Looking up and to the left. The main probably 12 GA Red wire is the ain feed to the fuse block. Also maybe easier to see how the bulbs are mounted."
 
"<[img]"http://www.marineengin

"
292281.jpg

Again JUST in case it helps. The purple wire that has been stripped a little (just below the blue and above the mystery other 12 GA purple) is the wire that becomes "hot" when the ignition is turned on to "run". Also the one that I used with the jumper to see what reactions other wires in the engine compartment."
 
"Steve...thanks for taking the

"Steve...thanks for taking the pics, hope you didn't wreck your back crawling around under there.

For the last pic with the 2 purple wires, I'm not sure exactly where you but it's possible the 2nd one comes out of the splice off the alternator and actually feeds power to the ESA?

On your main fuse pic, the purple wire coming from the left seems to go into the middle, is it the one I see that looks like it's been soldered?

I see the lights, they look like they are wired internally and must draw power off the gauge power so I guess they are on all the time when the engine is running.

Again on the main fuse pic, where are the purple and blue wires going that trail off to the left, to the ignition switch?"
 
"Please confirm if you have an

"Please confirm if you have an AMP meter or VOLT meter.
If you have an AMP meter, that is most likely where your problem is.
Then specify the color coding on the cables. Purple/blue are B+ from battery, while purple are 'ign' out of key."
 
"Morton

The meter says &#34

"Morton

The meter says "VOLT". The ignition is a three pole switch. Red, from the battery; Yellow with a red stripe is for the ignition and then the
*#&%*^@ Purple. It runs into the harness and comes out behind the engine. I have tested this wire and has continuity and no shorts.

NOW, here is another thing that is bothering me. ALL of the schematics that Bob linked me to and the ones in the manual I have show a "DARK BLUE" connecting all of the gages. I am wondering if I don't have the Dark Blue wire because I do not have a 'Trim Indicator'?"
 
"The trouble that the colors d

"The trouble that the colors does not fit might be related to that you do not have an OMC harness in the boat!
Hooking this up in no rocket science.
I will try to be back later, unfortunately I do not have any diagrams, but if you got an ohm-meter there should be no big problem."
 
"Steve...don't get hung up

"Steve...don't get hung up on the blue wires in the diagram, the wire coming from the ignition switch looks blue in the diagram but you see the "PU" pointing at that wire indicating it's really purple. The other wire is DBL (dark blue), this is for the gauge light power but as I said earlier it looks like your gauge lights are wired internally to the gauge power."
 
"Bob
Thank you for all the he

"Bob
Thank you for all the help. I had my daughter slide up under there and she took them. Also they (Daughter and Son) have drug me into the 1990's screaming and kicking. They bought me a wireless connection, so I am in the shop with the laptop so I am not traversing the 100 yard round trip from the house to the shop, and then try to remember what I came looking for. I lost 10 pounds doing that, three trips to remember one thing.
The two purple wires are different gauges the little one that has the cut exposing the copper wire is the one that goes go from the ignition to the alternator. I am sorry, but I cannot figure out the acronym "ESA"?

RE "Fuse Box Pic: Good eye, and dumb me, you are exactly right! It is the conversion of all of the purple wires for the gages!! I was going to write about this in the picture.

The gang of wires hanging vertical in the pic is the wire bundle for the gages. Overexposed, I wish I had taken the time to enhance the colors, and I will if needed.

On the left center of the pic is one of my black jumper wires connected to the VOLT gage connector.

The three wires that run right along the metal steering rack (Left to right,the three wires that run in between the three bolts are from the ignition that you and Morten was asking about, red, yellow with a red stripe and the purple."
 
"One last thing. I bought a [

"One last thing. I bought a Cable Tracker at Harbor Freight today, around $30. In case you want to read up on it, its item number 94181. It should be in Harbor's on-line catalog."
 
"Let us start.
From the harne

"Let us start.
From the harness you should have:
-One 'big' red/blue stripe going to fuse box (B+) and another smaller going to ignition switch.
-One yellow/red going to ign switch from starter.
-One purple from switch to ign (coil).
If you want instruments to go on with ign, this even has to go from switch to instrument+ (including volt meter)
- One blue from oil pressure sender to instrument 'signal'.
- One brown from temp sender engine to temp instrument 'signal'.
-One gray from coil to rev counter 'signal'.
-One Black ground.(to all instruments ground from a common ground point).
If these colors does not fit what you have, just identify the cables by ohm from respective engine end to instrument end."
 
"Thanks Morten
Above all of t

"Thanks Morten
Above all of the pictures is a post from Bob that had the links to the various schematics for this monster. I think you were correct in calling out that this harness is NOT OMC! The colors you have listed are correct. We knew what the wires were going to, it was because the gauges weren't working when I first took the boat out was the original reason for the forum/post. Thanks again because I did jump in the boat (I am just finishing up 10:01 in CO) and double checked and I had one of the connections labeled wrong, so THANKS!
I AM GOING IN TO HAVE SHRIMP AND CELEBRATE. see the next post!"
 
"Hey Guys.......
I THINK I FO

"Hey Guys.......
I THINK I FOUND IT!!! The new toy helped me find the rascal! I don't believe it. I cannot figure out how they ever worked in the first place! In the picture, "Fuse Box", it is real hard to see. There were other purple wires that were everywhere under the dash. Some not going anywhere and then there was one purple wire that was taped up to two blue wires. I thought the tape was just holding a purple and two blue wires together. These were way up high around the fuse box and real hard to find! (Of course!) When I took the tape off, the wires were soldered together, the same type of solder job that all of the purple wires to the gages had. I guess what i am saying that the solder job was professional, from the factory?

I followed the blue with the new toy all the way up to above the fuse box, where there is a ground "box". When I cut the purple from the blue wires, everything worked. When I turned the key on, the fuel, and the volt gauges worked. I haven't been able to figure out the lights on the dash yet. The only thing left is to figure out why the lights are not working. God, I hope I am not on a "high" only to find that I still have problems, but I am thinking positive, LOL. I will try to remember to take a pic of where the wires were soldered together.

Also I noticed that the one link for the schematics showing the dash it shows that there is a "Link" in between the tachometer and distributor. This schematic shows it is close to the tach. Any ideas? I ave not started it yet to check on the rest of the gages.

For now, I am heading to the shower and then shrimp and a cocktail!

Thanks to everyone that has helped me so far, but please give the light problem a thought?"
 
"Happy it is sorted out. The w

"Happy it is sorted out. The whole post got a bit long, and sometimes schematics may be a bit confusing when colors do not match. I'm lucky as I have no books and work mainly from memory (experience) and adding a bit from the net.
I would however advise you to run the B+ (ign) from switch to panel through a fuse. If one of the instruments/senders shorts out, it will not kill your engine. Only exception if the rev-counter shorts out!"
 
"Two ways to get the lights wo

"Two ways to get the lights working.
If you want them on with ignition, just make a jumper from B+ to light terminal on the instruments.
If you want the lights to go on with nav lights, make a jumper from nav-light switch/fuse to each of the light terminal on the instruments."
 
"Good find Steve!

Sorry the

"Good find Steve!

Sorry the ESA is your Electronic Shift Assist module, you can see it near the middle top of the engine schematic.

As for the lights, I'm looking at your 3rd pic down, it shows the speedometer with the black hose attached at the back, maybe it's just the angle but I don't see any connections on the back? The black piece at the top should be the lights in all of your gauges, have they ever worked? Have you ever taken them out to see if there are bulbs in there? They should just come out with a twist.

ps...I went and read about your cable tracker tool, quite the little tool but I don't know if I would get one, it seems like it would a lot of the fun out of chasing down these kind of wiring challenges
rofl.gif
"
 
"WHOOPS I forgot that I have t

"WHOOPS I forgot that I have to race tomorrow night, sheesh. So I will have to wait until next week to get back to the boat. Now it's thrashing time to get the car set up, DUH
Steve"
 
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