water temp gauge


New Member
Question: Wiring connections for newly added water temp and oil pressure gauges.

Had a overheating problem on my 2014 Mercury 90hp 4 stroke outboard that I diagnosed as a
stuck thermostat and fixed!

In the process of troubleshooting the overheating problem I discovered 2 sender wires
that were not connected in my steering console. 1 tan labeled water temp and 1 blue
labeled oil pressure. When I had this engine installed on my boat, new by a Mercury Dealer,
I did not have a water temperature gauge or an oil pressure gauge, so they left them unconnected.
The engine has a water temp sensor 885342002 and an oil pressure sensor 897447002 installed
on the engine starboard side, near the oil filter. See attachments.

So I thought this would be a good time to install these gauges to monitor engine temp and oil pressure!
I "assumed" that these sender wires were connected to the engine sensors!
Gauges are hooked up but are not responding. I found 2 capped wires on the starboard side of the
engine (see attachments) 1 tan and 1 blue. I have not check yet if these wires are the same wires
in the console. There are 2 wires coming out of each engine sensor and plugged into connectors.

Question: If these capped wires in the engine are the same wires that are in the console,
where do I connect them to in the engine wiring harness?
I would think 1 wire from the sensor is connected to the Guardian safety system and 1 wire would
go to a gauge sender connection. The sensor body is grounded to the block via the threads.
Do I have to install extra engine sensors????