View Full Version : Broken wire - what is it from?

07-21-2012, 11:21 AM
Hi folks, I just noticed a small section of a wire cover was damaged and on further investigation I see what appears to be a broken wire.

This is a 97 TBI. I'm wondering if anybody knows where this wire should go and what the sensor is for that I circled in the attached picture.


07-22-2012, 11:26 AM
If I'm looking at it correctly, that wire is going to your water temperature sensor.

I have no idea what the other broken wire is for. You'll have to trace it back to the source (probably a terminal block) and try to find a wiring schematic to determine what it's for.

Does everything seem to be working ok with your boat electrically?

07-23-2012, 01:08 AM
Thanks for the response. I think you're right that it's a temperature sensor. From what I can tell, there's two temperature sensors: one for the ecu and one for the gauge. I think this one is the latter.

Electrically I think everything's ok with the boat. Sometimes the boat hesitates while accelerating but that seems like a fuel issue. At first I was hopeful that a broken wire to a sensor might be related. I had a mechanic check the boat last year and he didn't find any engine codes or sensor issues.

It's tricky to trace the wire because it goes to the back of the engine with a whole bunch of other wires but I'll give that another try.

07-23-2012, 01:48 AM
If you can't find anything, I'll try to remember to look at mine the next time I have it out. Our engines should be similar...


07-23-2012, 05:49 AM
Has the temperature sender previously been a two wire sender and now only a one wire unit earthing through the motor. If you check the resistance to earth on a multimeter it would confirm if it is connected to your earthing block.

07-23-2012, 05:51 PM
My 95 TBI has two wires running in the same harness. They look almost white but they are a very light tan color. The solid tan wire goes to the temperature sending unit for the gauge. The other tan wire has a black or blue trace. That wire goes to another sensor on the neck of the intake manifold where the thermostat housing is. That sensor (if yours has one) is for the idiot light on the dash "Engine Overtemp".

I'll look for a pic if I have one.

07-23-2012, 06:02 PM
On my 95, the two sensors are pretty close together. If your boat doesn't have the "Engine Overtemp" light on the dash, you won't use that wire.

07-23-2012, 06:07 PM
Is that your second sensor with the yellow arrow?

07-23-2012, 09:16 PM
I only have one sensor in that area I believe. Here's another picture zoomed out a little.

I have two idiot lights: one for transmission temp and the other is a check engine light. Perhaps the wire is there for a light my boat doesn't have.

Peter - I was wondering the same thing about a positive and a ground. All I know is that the temperature gauge works fine. I have a multimeter, but barely know how to use it. What resistance am I looking for between the sensor and the ground?

Thanks for the responses guys.

07-23-2012, 10:04 PM
Since you don't have the "Over Temp" light and there is a bolt in place of the extra sensor, I'd guess that the wire isn't used. If it is tan with a black trace, I'd almost bet on it.

07-23-2012, 10:09 PM
I think Hudgins has the idea about the other sensor, but if you put your multimeter on ohms and ground one wire to the engine block, then place the other one on the end of the broken wire it will tell if that wire is earthed out by showing little or not resistance to earth. Have fun.

07-25-2012, 01:44 AM
Yeah that makes sense to me that it's just an extra wire. It appears to be the same color as the other sensor wire (tan or maybe it was white when new). Thanks again!