A second set of the same New Gauges don't work???

[iambler]

Hi Group,
I have a 2019 Mercury 90 HP 4 Stroke Outboard engine, that I have just installed a SECOND set of two gauges into, which still don't work, after a second try.???
These are connected to a Mercury Wiring Harness going directly to the engine.
When I turn the key on, the needle of the Water Temperature Gauge "bumps" or jumps a little [showing me that it IS receiving power] but neither gauge works?
The dash lights do work with these gauges, when turned on (?).
- These were wired/connected by my Marine Mechanic, so I assume he knew what he was doing.
WHY DON'T THESE GAUGES WORK?
--- I read when I purchased these gauges that each requires it's own Sender Unit, and one gauge uses a "C" Sender and one uses a "D" Sender.
--- I have no idea if my New-in-2019 Mercury O/B came with these Sender Units.
I wouldn't know where in the engine to look for these Senders anyway.
BTW - both are Sierra Amega Gauges.
Could anyone HELP ME with this dilemma!
Thanks!
Irv in Maine/iambler

 

[alldodge]

You mention 2 gauges and mention Temp but what is the other gauge?

Analog gauges will have 3 wires connecting. May also have another wire to light gauge
Water Temp, Purple (12V power), Black (ground) Tan (sensor)

At the motor find the Tan wire and follow it to the Temp sensor. To test the gauge, remove wire from sensor, turn key ON (do not start) and ground wire to block. This should peg the meter hot

 

[iambler]

You mention 2 gauges and mention Temp but what is the other gauge?

Analog gauges will have 3 wires connecting. May also have another wire to light gauge
Water Temp, Purple (12V power), Black (ground) Tan (sensor)

At the motor find the Tan wire and follow it to the Temp sensor. To test the gauge, remove wire from sensor, turn key ON (do not start) and ground wire to block. This should peg the meter hot

Hi Alldodge, I bought ALL new gauges: Speedometer, Tachometr with engine hours, fuel, trim, voltmeter, water temp and Oil Pressure.
- The 'second' of these two gauges which I replaced was the Oil Pressure Gauge.
It was the Wate Temperature and Oil Pressure which didn't work.
Thanks for you reply!
Irv in Maine

 

[alldodge]

Oil pressure gauge works the same, look for light blue wire

 

[iambler]

Oil pressure gauge works the same, look for light blue wire

Hi Alldodge, Thanks for your reply.
I have a 'dumb question'...
Did my [new-in-2019] 90 hp Mercury 4 stroke Outboard Engime COME with a Sender Unit for an Water Temperature Gauge and Sender Unit for an Oil Pressure Gauge???
Two out of two brand new gauges showed no response, so I'm just wondering.
- My Marine Mechanic [who IS GOOD/REPUTABLE] would have and should have KNOWN about these two Sender Units, correct?
- One Sender Unit is "Code "C" and the other is Code "D", by the way, according to what I read after each gauges description in the online listing, from "Go2Marine" where I bought them.
- Thanks!
Irv in Maine

 

[alldodge]

Do not know if your motor came with the senders or not.

The Mech should know how to connect and "IF" they are on the motor

Don't know what a code C or D is. Have a link I can read what it is?
Most Marine senders come in either North American or European versions

 

[Silvertip]

Assuming the "mechanic" knows how to connect this stuff if a stretch. They may know which end of a wrench to hold but many have less electrical knowledge than the average boater. Two sets of identical instruments that fail to work says it's a "workmanship/knowledge" issue or a the engine doesn't have the senders. Oil prssure, fuel, water temperature and trim all require sensors/senders. Voltmeter is not engine engine dependent.