VP 2003 oil and temp senders.

[madabouttheboat]

I have a fresh water cooled 2003 that came with the basic instrument panel. This means it does not have oil pressure or engine temperature guages, only an audible alarm. The senders fitted to the engine are essentially switches, either off or on, alarm or no alarm.

There was a ‘deluxe’ instrument panel available with the 2003 that had these gauges. The wiring diagram for my engine shows the two ‘switches’ (3 and 4 in the first pic)

The wiring diagram for the deluxe setup (pic 2) shows four senders (1,2,3 and 4) Two switches for the alarms and two variable resistance senders to drive the gauges.

My question is; where do these additional senders go in the engine? I can’t seem to find that info anywhere. Does anyone have the deluxe version and can have look for me?

Thanks

 

[Boater Sam]

Surely the senders replace the switches?

 

[VicS]

Surely the senders replace the switches?

ITYWF the switches remain to give audible alarms, and warning lights, for low oil pressure and overheating.

 

[madabouttheboat]

ITYWF the switches remain to give audible alarms, and warning lights, for low oil pressure and overheating.

Thats how I understand it. The wiring diagram shows four with separate wires going to different terminals. I just don't know where they go on the engine.

 

[SeaPhoenix]

Thats how I understand it. The wiring diagram shows four with separate wires going to different terminals. I just don't know where they go on the engine.

On my AD31B, senders are adjacent to the alarm switches. Hope that might narrow down your search?

 

[wonkywinch]

If the engine manufacturer hasn't drilled and plugged spare holes for optional gauges, it's normal to fit a T piece so both a switch and gauge can be fed from the same hole.

Senders are standard sizes so automotive stuff can be used.



My biggest fear is the sea water being blocked by a plastic bag or an impellor failure. By the time the engine block temperature alarm sounded, it may be too late to prevent damage.

I fitted an exhaust mixer temperature probe and set it to 40C. It triggers the Yanmar buzzer and an additional big red LED. If I restart a warm engine, the alarm sounds for a few seconds until the water cools the mixer that warmed >40C due to conduction after engine shut down.

I use this to confirm adequate water flow after restart (as well as checking exhaust output as usual). Here's my post about this.

Post in thread 'Exhaust temperature alarm'

1 Oct 2025

I installed one of these with the probe pushed into the edge of the pipe where the elbow meets the exhaust hose. I set it to alarm at 40C and it works well.



I added a large red LED on the helm station and wired the stat into the buzzer circuit on the Yanmar B20 panel so if the exhaust overheats, I get audible and visible alarms. The way I wired it, the large red LED also comes on if the standard oil pressure or coolant temp switches activate.

This is how I wired the above, everything to the right of the dotted line is my mod.



Link to stat £9 on Ebay...

• wonkywinch

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