Upgrading Merc A1-G1 Oil Pressure Light with an actual oil pressure gauge.

[1985 Century Mustang]

On my 1985 Merc A1-G1 3.0 I have just an oil light on my panel, which would be red if there were an issue with the oil pressure. I'd like to replace that with an actual gauge. **Question** - Can I just swap out that light and install an actual gauge. Can anyone advise or send a link on which one to purchase, I'm not sure of how many terminals would be on the back of the actual gauge, because I never had one. I'm assuming one ground terminal, one power terminal, and one sending wire terminal that comes off the sender from the block.

Thanks

 

[ESGWheel]

This is doable but will require a new sending unit (sensor). Here is one I found on Amazon for a great price link. And yes, three wires: +12V and Ground to the display and then another single wire from the new sensor to the display. For that wire you could use the existing wire run that the light uses. Note the reading may be sensitive to the length of wire from the sensor to the display, ie it may read a little off if this wire is much longer then the one it comes with, but frankly should not be an issue.

 

[1985 Century Mustang]

This is doable but will require a new sending unit (sensor). Here is one I found on Amazon for a great price link. And yes, three wires: +12V and Ground to the display and then another single wire from the new sensor to the display. For that wire you could use the existing wire run that the light uses. Note the reading may be sensitive to the length of wire from the sensor to the display, ie it may read a little off if this wire is much longer then the one it comes with, but frankly should not be an issue.

Wow great price Thanks, appreciate that, however I think I'm going to go with just a regular oil pressure gauge, non digital. Can you send me a link for that too. Thanks

 

[ESGWheel]

Here is one that also has a ‘dash light’ connection > if you have dash lights it will also link

 

[1985 Century Mustang]

Question: On the back of the oil pressure light there are only two wires, and they are both black. One black wire goes from the back of the light (I think) to to the sender wire, which then that wire connects to a white wire, the other wire goes to positive on the ignition switch. Does this make sense, or should there be 3 wires? I only see two. **Is the sender considered a ground also?

 

[Scott Danforth]

your oil pressure light uses an oil pressure switch. with no oil pressure, the switch is closed. when your oil pressure is above 7 psi, the switch opens. the switch provides ground to the light.

the two wires coming out of the light do not matter with incandescent lights. one goes to the switch, one goes to an ignition power source. since they did not matter with regards to polarity, the older lights were all wired with the cheapest wiring they could get, which in this case is black. later LED lights have different colored wiring. follow the black wire to the terminal or splice. the other side of the terminal or splice should be light blue.

oil pressure wire in the harness should be light blue.

a gauge uses 3 wires. + VDC, ground, and signal. the oil pressure sender is a variable resistor to ground which.

you can not use the gauge with your current oil pressure switch. you need an oil pressure sender.

 

[1985 Century Mustang]

your oil pressure light uses an oil pressure switch. with no oil pressure, the switch is closed. when your oil pressure is above 7 psi, the switch opens. the switch provides ground to the light.

the two wires coming out of the light do not matter with incandescent lights. one goes to the switch, one goes to an ignition power source. since they did not matter with regards to polarity, the older lights were all wired with the cheapest wiring they could get, which in this case is black. later LED lights have different colored wiring. follow the black wire to the terminal or splice. the other side of the terminal or splice should be light blue.

oil pressure wire in the harness should be light blue.

a gauge uses 3 wires. + VDC, ground, and signal. the oil pressure sender is a variable resistor to ground which.

you can not use the gauge with your current oil pressure switch. you need an oil pressure sender.

My boat has a regular oil sender. I need a different sender, correct?

 

[ESGWheel]

Yes u need a different oil sender
It’s included with the link I posted

 

[Scott Danforth]

My boat has a regular oil sender. I need a different sender, correct?

do not confuse the oil pressure switch you have with a gauge sender.

 

[1985 Century Mustang]

do not confuse the oil pressure switch you have with a gauge sender.

After I put in the new sender and gauge, can I still use the original blue wire that was on the old sender for the new gauge?

 

[ESGWheel]

see post no. 2