Lost trim gauge and water temp indications

[Franco_boater]

Hello
I wanted to put my boat into the water after winter.
Boat runs great with new impeller and exhaust gaskets BUT…
Trim gauge doesn’t work and water temp…
Before winterisation everything was fine…
How to check if the sensor is ok or check the signal to the gauges ?? Thank You for help
When I turn the key to the ignition position, all other gauges wake up but water temp and trim sensor does not…

 

[nola mike]

1. Locate the sensor.
2. Verify that you have 12v in
Key on:
3. Disconnect the sender wire. Gauge should go to 0.
4. Ground sender terminal, gauge should peg

 

[Franco_boater]

Hello thanks for fast reply. I’m good at turning wrenches but hate electrics can you please tell me how to check it. I have boat on the trailer so far … but wish to drop it finally

 

[nola mike]

can you please tell me how to check it.

I thought I did... I'll try again
Step 2 just use a voltmeter connected to ground on 1 side and sender wire disconnected on the other side (tan is water, brn/wht trim). You should get 12v, gauge reads 0/all the way to the left. Next ground the sender wire, and the gauges should peg to the right.

 

[Franco_boater]

Do You mean at the instrument gauges or at the engine bay?

 

[Franco_boater]

I thought I did... I'll try again
Step 2 just use a voltmeter connected to ground on 1 side and sender wire disconnected on the other side (tan is water, brn/wht trim). You should get 12v, gauge reads 0/all the way to the left. Next ground the sender wire, and the gauges should peg to the right.

1st step isn’t actually a grounding? Ground on 1 side gauge on the other = grounding right? I don’t get your instructions sorry I’m not English speaker like You

 

[nola mike]

Do You mean at the instrument gauges or at the engine bay?

Engine bay

1st step isn’t actually a grounding? Ground on 1 side gauge on the other = grounding right? I don’t get your instructions sorry I’m not English speaker like You

One lead of the gauge goes to engine ground, the other goes to the (tan, or brn/wht) sender wire

 

[Franco_boater]

I will have to find trim gauge wires , can you tell me where to search? I think it will be 2 wires right?
But for the water temp sensor I’ve only 1 brown wire which goes to the sensor in the thermostat housing . Is that right?

But actually both trim and water temp sensors are dead, full to the left even when switching the key.
But for example tachometer or oil pressure gauge wakes up with ignition

 

[nola mike]

I will have to find trim gauge wires , can you tell me where to search? I think it will be 2 wires right?
But for the water temp sensor I’ve only 1 brown wire which goes to the sensor in the thermostat housing . Is that right?

Yes. Trim sender wires are somewhere coming in through the transom.

But actually both trim and water temp sensors are dead, full to the left even when switching the key.

Yes, doing the tests will help you figure out whether it's the wiring, the senders, or the gauges.

 

[Franco_boater]

Thanks , Can you tell Me How to ground the sender ?

Ok so
1. Cable connected to the Ground 1 side and 2 side to the wire from the gauge, should go to the right.
2. 12V Voltometer, 1 side to ground 2 side to wire from sender and should be 12V on the Display?

 

[Bondo]

Thanks , Can you tell Me How to ground the sender ?

Ok so
1. Cable connected to the Ground 1 side and 2 side to the wire from the gauge, should go to the right.
2. 12V Voltometer, 1 side to ground 2 side to wire from sender and should be 12V on the Display?

Ayuh,..... For the temp sender, in the t-stat housing, remove the brown wire, the gauge should be zero,.....
Ground that wire to the t-stat housing, the gauge should go Full Hot,.....

For the trim sender, there's 2 black soft wires coming through the transom housing, just above the drive shaft, 2 black wires, 2 conductors each,.....
One is the trim sender, the other the trim gauge,.....

Those wires, Suck, they rot, 'n break off outside the transom very, very often,....
Probably the worst choice of available wire by any company, any where, ever,....

 

[Franco_boater]

Thanks for clarity, and do you know Which one of 2 wires is for the gauge I should check?
But it worked before I put it in the trailer , after winter it’s gone…

 

[Bondo]

Thanks for clarity, and do you know Which one of 2 wires is for the gauge I should check?
But it worked before I put it in the trailer , after winter it’s gone…

Ayuh,..... The one that goes to the gauge,.....

They look identical,..... one will meter a varying resistance to ground, the other will be a make, or break switch,....
The make, or break is wired in-line with the up trim button, it opens at tilt,....

Start yer inspection outside the boat at the senders on either side of the gimbal,....
I'm bettin' that's where the problem is,....

 

[Franco_boater]

Ayuh,..... The one that goes to the gauge,.....

They look identical,..... one will meter a varying resistance to ground, the other will be a make, or break switch,....
The make, or break is wired in-line with the up trim button, it opens at tilt,....

Start yer inspection outside the boat at the senders on either side of the gimbal,....
I'm bettin' that's where the problem is,....

I have checked and looks normal to me… even I’ve wiggled and nothing

 

[Bondo]

Well, pull the sender apart on the gimbel housing, 'n look for a problem there,......
If the wires ain't broken, 'n the sender is good, you'll see varying resistance testin' the wires, with an ohm meter, as the drive is lifted or dropped,.....

 

[achris]

Hello
I wanted to put my boat into the water after winter.
Boat runs great with new impeller and exhaust gaskets BUT…
Trim gauge doesn’t work and water temp…
Before winterisation everything was fine…
How to check if the sensor is ok or check the signal to the gauges ?? Thank You for help
When I turn the key to the ignition position, all other gauges wake up but water temp and trim sensor does not…

When asking about engine problems, please include details of the engine. Model, year, serial number, in the first post of each thread... That would be nice.

Yes, you have a lot of posts about your engine in other threads (I've read all of them), but we are also reading dozens of threads covering every engine Mercruiser produced in the last 50 years... We can't always remember which engine YOU have... This is important because wring can be different on different engines, and depending on the year too.

Chris........

 

[Franco_boater]

You are right I’m sorry I will try to remember that.
it’s TKS 2005 Merc 4.3

 

[achris]

Water temp gauge sender (in the engine) will have a single tan wire. Short that to ground and, with the key ON, the gauge should read high.

Trim sender wire should be brown/white.

 

[Scott06]

Thanks for clarity, and do you know Which one of 2 wires is for the gauge I should check?
But it worked before I put it in the trailer , after winter it’s gone…

The trim sender wires come out of transom and go into the engine harness and make their way up to the helm. The trim limit wires go directly to the trim pump