Cockpit instrument panel works sometimes

[ChrisW]

The engine gauges on the cockpit instrument panel work only about half the time. My thought is there is some corrosion somewhere, but I have not been able to find it.

The gauges either all work or none work (tachometer, fuel gauge, engine temperature).  However, when they aren't working, if the engine is running and I turn the key to heat the glow plugs, the gauges will work as long as I hold the key in that position.  When I release they key they stop working.

Does anybody have an idea what's going on or where I should look to fix the problem?

[KWKloeber]

Chris what troubleshooting have you done to isolate the cause?

Which engine do you have?

With no other info I'd suspect a bad key switch but.....

[scgunner]

     Chris,

        KWKloeber is right the more information you post the more help you're likely to get. Example, if you post the year and model that will key in the guys who have the same boat and may have run into the same problem. When you looked for corrosion did you pull the panel so you could check behind it? I'm not familiar with your ignition switch, on my boat the keyed ignition switch is ON/OFF only and I have a separate button for the glow plugs.

         Based on the information you provided I would suspect a faulty ground. In an instrument panel the instruments can all be run off of one ground nearby, it saves unnecessarily long wire runs. Power on the other hand usually comes from a variety of sources which would seem to make it unlikely that there would be a failure from multiple sources.

       

[ChrisW]

I have a 1994 with a Universal 25-XP engine.  The ignition switch is a keyed one with on/off/glow. A separate button starts the engine.

[ChrisW]

     Chris,

        KWKloeber is right the more information you post the more help you're likely to get. Example, if you post the year and model that will key in the guys who have the same boat and may have run into the same problem. When you looked for corrosion did you pull the panel so you could check behind it? I'm not familiar with your ignition switch, on my boat the keyed ignition switch is ON/OFF only and I have a separate button for the glow plugs.

         Based on the information you provided I would suspect a faulty ground. In an instrument panel the instruments can all be run off of one ground nearby, it saves unnecessarily long wire runs. Power on the other hand usually comes from a variety of sources which would seem to make it unlikely that there would be a failure from multiple sources.

       

I did pull the panel out. I replaced some connections in there where the wire strands were coming out, but to no avail.  I checked the resistance in the wire from the battery to the ignition and it was fine.  I couldn't find a good path though from the panel to the DC negative bus.  So what you are saying makes sense.  I do get 12+ voltage between the battery connection on the ignition switch and the connection labeled "solenoid".

Since I first posted I found a wire that looks like it should be a ground for the instruments, but I am not sure.  I am finding now that there is no connectivity through it to the negative bus bar. So it looks like that might be it. I will try to trace this wire. 

[KWKloeber]

Chris

Do you still have the oem Gummy Bear plugs behind the panel and in the engine space?
Are you saying you have a neg buss in the engine space.  Pictures!

The panel ground is the #10 black wire in the harness, probably coming off a gauge negative post, like the tach. On the (oem) m-25/XP, it terminates on one of the exhaust manifold studs (terrible place) so it uses the engine and battery negative cable on (oem) a bell housing bolt (poor location.)

A poor ground could cause the symptom, because the only function of the panel negative is for the gauges and blower. All else depends on the engine ground. However, because it disappeares when preheating, that wouldn't affect the ground.  If PO did work, any/all bets (below) are off.

Gauges are powered thru the I terminal of the key switch. Preheat is thru the S terminal, which also energizes the I terminal. Bet a beer? Replace the switch and at least that one problem will disappear.    If the engine electrical is oem they'll be others.

You can prove it out — when the key is in the I position (and no gauges,) with a screwdriver short from the B terminal (red power feed) to the I terminal and you **should** have your gauges.

Use a Cole Hersee 3 position sw with a weather boot:

https://www.defender.com/product.jsp?path=-1%7C328%7C2290051%7C2290053&id=617149
https://www.defender.com/product3.jsp?path=-1%7C328%7C2290051%7C2290062&id=917192

While you're in the weeds, replace your start switch:

https://www.defender.com/product3.jsp?path=-1%7C328%7C2290051%7C2290054&id=618206

[ChrisW]

Chris

Do you still have the oem Gummy Bear plugs behind the panel and in the engine space?
Are you saying you have a neg buss in the engine space.  Pictures!

The panel ground is the #10 black wire in the harness, probably coming off a gauge negative post, like the tach. On the (oem) m-25/XP, it terminates on one of the exhaust manifold studs (terrible place) so it uses the engine and battery negative cable on (oem) a bell housing bolt (poor location.)

A poor ground could cause the symptom, because the only function of the panel negative is for the gauges and blower. All else depends on the engine ground. However, because it disappeares when preheating, that wouldn't affect the ground.  If PO did work, any/all bets (below) are off.

Gauges are powered thru the I terminal of the key switch. Preheat is thru the S terminal, which also energizes the I terminal. Bet a beer? Replace the switch and at least that one problem will disappear.    If the engine electrical is oem they'll be others.

You can prove it out — when the key is in the I position (and no gauges,) with a screwdriver short from the B terminal (red power feed) to the I terminal and you **should** have your gauges.

Use a Cole Hersee 3 position sw with a weather boot:

https://www.defender.com/product.jsp?path=-1%7C328%7C2290051%7C2290053&id=617149
https://www.defender.com/product3.jsp?path=-1%7C328%7C2290051%7C2290062&id=917192

While you're in the weeds, replace your start switch:

https://www.defender.com/product3.jsp?path=-1%7C328%7C2290051%7C2290054&id=618206

I will post pictures next weekend; I  have to remove a chainplate the rest of the day.   Not sure if I have gummy bear plugs.  Should the panel ground be connected to the negative bus behind the electrical panel near the chart desk?  That is what I had thought..  I think I've identified the correct panel ground wire like you describe. 

I should have mentioned that the key switch is new.  I bought it from catalinadirect about six months ago. I installed it myself so it is possible that I hooked it up incorrectly, but I kept track of which wires go where, and I had the same problems now as I did before.  The new one has a boot.

Thanks so much for the help.

[KWKloeber]

As I said.

Panel negative:
On the (oem) m-25/XP, it terminates on one of the exhaust manifold studs (terrible place) [with a ring terminal under the nut]  so it uses the engine and battery negative cable on (oem) a bell housing bolt (poor location.)

NO, OEM the negative does NOT run to the panel neg bus bar. The battery neg cable is right there, no need to run to the oanel.

If PO rewired, who knows??

-ken

[ChrisW]

As I said.

Panel negative:
On the (oem) m-25/XP, it terminates on one of the exhaust manifold studs (terrible place) [with a ring terminal under the nut]  so it uses the engine and battery negative cable on (oem) a bell housing bolt (poor location.)

NO, OEM the negative does NOT run to the panel neg bus bar. The battery neg cable is right there, no need to run to the oanel.

If PO rewired, who knows??

-ken

Found where the panel ground connects to the engine.  There are two wires hooked there, the largest one goes to the battery.  The smaller one looks about the same size as the wire I identified as the panel ground behind the panel, the only wire of that color and size..  However, that large black wire from the panel does not connect to the one on the engine.  Instead, a smaller red wire is the only one that seems to connect to it.  And this smaller red wire is hooked up to a corroded switch for a blower that I have no idea if it exists or works.  Did Catalina install blowers? 

It's getting too dark now but it looks like I can just connect that red wire to where the large black wire is currently, but that doesn't seem right.  I don't know, but it looks like to me that someone cut the panel negative wire and spliced a small (maybe 16awg) wire onto it.  Why I have no idea.

Thanks so much for your help.

[KWKloeber]

Chris

I cannot follow what you're describing...

The panel ground attaches to the engine.  Where on the engine?  PICTURES!  Are you saying a battery cable?? Or just a heavy wire that goes to the battery?

But the large wire from the panel does not attach to the engine.  WHAT large wire? Color?
I have NO idea what you are describing.

What colors? What gauge wire?  PICTURES!!

It seems you're chasing wires with no plan/troubleshooting.
Did you do the test I said to isolate whether it's a power problem or a negative problem?
With the key ON (and gauges not working) short the switch B terminal to the I terminal.  Do the gauges work?

Catalina installed a blower under the coming, the toggle switch being on the cockpit panel.
Red is not a negative (or **shouldn't** be anyway.)

i.e., need MORE and BETTER/COMPLETE info!  It's ok if you don't know the precise/accurate terms or whatever, there's a lot of peeps who are ignorant of the wiring -- it isn't user-friendly!  But then you have to give us complete info and pics.

Q?  Did you download a manual? 
There's a schematic with all the harness wire gauges and colors and connection points at the engine components.  Well, what the colors **should be** anyway -- again if a PO had hands on it, then yah nevah know. The panel negative is wire #1 in the harness and thru the gummy bear plugs.  Do you still have the plugs or are they gone?


I have an Excel file that lists what the harness wires SHOULD be on the M25/XP.   Sometimes the colors vary on the tach signal and the preheat circuit.  I can't attach an XLS file, but could email it?


-ken

[KWKloeber]

I temporarily stuck the file here:

http://c34.org/wiki/images/b/b7/Copy_of_David%27s_engine_harness.xls

-ken

[ChrisW]

Chris

I cannot follow what you're describing...

The panel ground attaches to the engine.  Where on the engine?  PICTURES!  Are you saying a battery cable?? Or just a heavy wire that goes to the battery?

But the large wire from the panel does not attach to the engine.  WHAT large wire? Color?
I have NO idea what you are describing.

What colors? What gauge wire?  PICTURES!!

It seems you're chasing wires with no plan/troubleshooting.
Did you do the test I said to isolate whether it's a power problem or a negative problem?
With the key ON (and gauges not working) short the switch B terminal to the I terminal.  Do the gauges work?

Catalina installed a blower under the coming, the toggle switch being on the cockpit panel.
Red is not a negative (or **shouldn't** be anyway.)

i.e., need MORE and BETTER/COMPLETE info!  It's ok if you don't know the precise/accurate terms or whatever, there's a lot of peeps who are ignorant of the wiring -- it isn't user-friendly!  But then you have to give us complete info and pics.

Q?  Did you download a manual? 
There's a schematic with all the harness wire gauges and colors and connection points at the engine components.  Well, what the colors **should be** anyway -- again if a PO had hands on it, then yah nevah know. The panel negative is wire #1 in the harness and thru the gummy bear plugs.  Do you still have the plugs or are they gone?


I have an Excel file that lists what the harness wires SHOULD be on the M25/XP.   Sometimes the colors vary on the tach signal and the preheat circuit.  I can't attach an XLS file, but could email it?


-ken

First of all, thank you for your patience with me here.  I have a tiny smartphone that I am usually reading and writing with on the boat.  At the moment I have a regular monitor and keyboard.  Perhaps I can be more clear now.  Sorry I don't have pictures yet but will post some this weekend.

I found, (or thought I found) using your advice, where the panel negative should attach to the engine.  It is way in the back near where the diagram in the manual said the exhaust manifold should be.  Both of them were black.  One was maybe a #4-#6 awg that I tested and connects to the batteries.  The other is maybe a #10 awg (black).  This #10 black does NOT connect to the #10 black that is attached to the back of the tachometer.  Instead, that #10 black from the engine is connected to a #14-#16 RED wire that goes into a defunct switch for a blower.

I do have a manual for the engine.  It came with the boat and is a hard copy in a binder. I don't have it handy with me now.  It shows wiring harness diagrams but is not very clear (to me anyway) where everything is hooked up.  It says that the panel negative eventually connects to the battery, but it does not mention how exactly.  Anyway, I do not trust that it accurately represents the actual wiring in my boat.

I have not tried shorting the wires on the key switch yet.  But I am pretty convinced it is a problem with the negative side.  I downloaded the spreadsheet you posted and will use it this weekend.  Thanks again.  You have been a lot of help.  Sorry if I still haven't been clear; maybe I will after posting pictures.

[KWKloeber]

I'm on my phone.m now.  I feel your pain.

Ok the two are likely on a bell housing bolt so the #10 gauge isn't there OEM was the PO made some mod.

The exhaust manifold is on the side of the engine (with the coolant fill pressure cap.). You may be referring to the exhaust flange or riser off the exhaust manifold?

If you have the new style alt bracket that bolts to the exh man studs that's where the OEM harness neg was.

To improve things the battery neg cable should be moved to a starter bolt, a heavy cable rin to a neg bus or a power post in the compartment and all your negatives run to that bus.

Presuming you have the basic charging setup, heavy alt out and alt ground cables should be run to the starter solenoid B post and to that starter bolt (bat neg cable.)

You may have a ground problem, but explain how energizing the glow plug circuit corrects that?  That's what doesn't make sense to me.

It doesn't make any sense that there would be a neg running to a blower switch, no matter what color the wire.

Lotsa pix, many angles. The panel also.

-k

[Ron Hill]

Chris : It has been my experience on a C34 that when some electrical thing isn't working correctly, it's a BAD ground or a bad inline fuse connection!!
 
I spent a couple of hours one afternoon bent over my engine instrument panel and soldered each and every ring connector. It only took a second to take each ring off its terminal and make sure that the wire in each ring was "electrically" connected. Just make sure that you don't have any corrosion.

To answer your question ... Yes, Catalina still installed a blower in boats with a diesel engine.  I used my blower before starting the engine, if I had had the Propane ON. Probably not necessary, but it was there so why not use it?

A few thoughts
 

[KWKloeber]

Panel negative:
On the (oem) m-25/XP, it terminates on one of the exhaust manifold studs (terrible place) [with a ring terminal under the nut]  so it uses the engine and battery negative cable on (oem) a bell housing bolt (poor location.)

Chris

Here are pix of where the harness negative might typically terminate:






Here's the gummy bear plug to look for (also behind the panel.)  Notice the OEM location of the harness negative ring terminal underneath the manifold stud nut.



And why you want to eliminate them:
http://c34.org/bbs/index.php/topic,8580.msg60715.html#msg60715

This thread and the forensics might help you a little with finding your way around the engine/wiring/other:
http://c34.org/bbs/index.php/topic,9567.msg72137.html#msg72137