1998 454 mag mpi , Trying to figure out what this sensor is one of the motors has nothing connected to it the other motor has what I believe is the trim limit while you're going into it for some reason , The trim limit sender sender was not hooked up on either motor and I'm putting them in and as I'm trying to find the wires I realized this one went to the sensor does anyone have an ideal of what the sensor is located next to the oil pressure sender?

Oil temp sensor

Oil temp sensor

how am I getting oil temp reading at the Guage when there not hooked up is the two oil temp sensors, the Pic with the wire going to sensor I'm 99% positive its the trim limit wire someone wired to it. The other motor has no wire going to sensor.

how am I getting oil temp reading at the Guage when there not hooked up is the two oil temp sensors, the Pic with the wire going to sensor I'm 99% positive its the trim limit wire someone wired to it. The other motor has no wire going to sensor.

If your oil temp gauges are working they are hooked to something. Maybe another temp sensor placed somewhere else.

If your oil temp gauges are working they are hooked to something. Maybe another temp sensor placed somewhere else.

If your oil temp gauges are working they are hooked to something. Maybe another temp sensor placed somewhere else.[/QUOTE]


ugh the trim limit switch wires were cut off at back of transom and trying to find wires they got o , wire diagram says brown and white wire , but the the oil temp wire on guages is brown white. Now I'm confused because I can't find another oil temp Guage . As I'm also replacing all my guages and putting in new senders , found all but oil temp sender , so the Pic I posted must be the oil temp sender and one of the guages must not have been working, as other motor didn't have wire hooked to that sensor. Its been 2 years since on water and I don't remember now if Guage worked.....
. I would think I would remember but last two years have been a **** show for me. I Just had all my interior done and doing my guages and dash , and did two new drives , was hoping to be on water by next couple weeks ( Arizona we boat 365) and have to get my new windshield put in to but this oil temp / trim limit wire has me Fuc$#!!! And stuck moving forward I'm trying to do hard stuff first and for me that's electrical, being color blind and asking wife every second what color a wire is VERY annoying, especially why she's at work and I have to wait for text back!! But thanks for replying wish boat's were like jeeps I could have 20 people here after posting in jeep forum , jeepers are like cockroaches pop up out of anywhere to help! I'm gonna see if I can find a mercruiser mechanic I can get to come out and identify my problem don't mind paying either , but I won't take to a shop to be told I need new everything lmao! Again that's for your input!! Truly appreciated

Robert,
It should be easy enough to trace a wire from the front to the back with an ohmmeter that has a "beep" function. All you really need is some wire long enough to reach. I have done it a couple of times on race cars where someone has wired the entire car with red wire

Good point, this has helped me in the past.

Robert, To elaborate a little further on this, take your ohm meter on the continuity setting where the meter beeps upon touching the leads together. Take a length of wire long enough to get from the helm to the engine, and then wrap it or clip it to one of the leads (doesn't matter which one). Then it's a matter of probing around until you get the beep, then you have 2 ends of the same wire. Or a good ground at both ends

I'm going to do that, What I think it is is they use the Brown white wire that is for the trim sender and use it for the oil Temp gages instead of the trim Sender gauge because I have mechanical Indicators for my Trim and drive. We'll have more of an issue of trying to find the oil temp sensor but one of the previous posts said the picture I posted was the oil temp center I think I'm just gonna relocate it as its on bottom of motor and I have a new sender unit for oil temp that came with guage so I'll leave old one and find new place for new sender sensor , I fu$^/ING HATE Electrical s*** Color blind never helps me out!!! Because now I need to figure out how to hook up trim limit switches when I have no wires for it there was trim limit and sender units on the back of the Outdrives but the wires were cut off as they went through the hull not sure if they were ever used at any time but I would definitely want Do you have a trim limit so I don't raise my drives too high Because even with my mechanical indicators I have raised my drive too high before my mistake!