Oil Gauge pinned with alarm

[jonny rotten]

98 5.0
Two issues. Not sure if they are related. First the oil alarm goes off with key in forward, not when key is off. If I take the orange/blue wire off sender it stops. Is that definitely a bad sender or could it be a ground? Second, The oil gauge is pinned high with key on or off. I replaced both the sender and switch by the oil filter with OEM parts. I pulled the blue wire off sender and it did not help. In another post I was having a no spark/no start issue and it was the ground in the main harness. I opened the ground pin a little and it fired up. Could there be another no contact issue in the harness causing any of these issues. Testing procedures?

 

[alldodge]

and your serial number is 0L072052

Your motor has 3 switches that will sound the alarm and all are connected using a Tan/Blue wire. Oil pressure, Water Temp, Drive lube. Any one of these will sound the alarm.

The alarm will sound when key is turned ON because of low oil pressure. Once motor starts the alarm should stop. Pull the Tan/Blue off the oil sender should stop the alarm with motor OFF. With this not happening, pull the Temp and lube bottle wires.

 

[jonny rotten]

and your serial number is 0L072052

Your motor has 3 switches that will sound the alarm and all are connected using a Tan/Blue wire. Oil pressure, Water Temp, Drive lube. Any one of these will sound the alarm.

The alarm will sound when key is turned ON because of low oil pressure. Once motor starts the alarm should stop. Pull the Tan/Blue off the oil sender should stop the alarm with motor OFF. With this not happening, pull the Temp and lube bottle wires.

Thanks, will test again with motor running and post back

 

[jonny rotten]

Right now it's pinned high with key off and with key on. With motor running it drops to zero. Nothing balances in between at any point. It's a new non OEM sender. Do these symptoms sound like a wiring issue or DOA sender? I was actually reading something about if the sender was from Europe it could be set up backwards and read pinned high with motor off instead of zero for whatever reason. But nothing balances out and reviews on sender make that unlikely....where do I go from here?

 

[alldodge]

If I take the orange/blue wire off sender it stops

Lets clarify some things
Your motor should have a Light Blue color wire on the oil gauge sender. The oil gauge sender looks like pic below



The oil pressure switch has 2 wires on it and looks something like this


Now if you bought a single wire switch that is small like the 2 wire one above then that is why the gauge is pegging

 

[jonny rotten]

Lets clarify some things
Your motor should have a Light Blue color wire on the oil gauge sender. The oil gauge sender looks like pic below

View attachment 408240

The oil pressure switch has 2 wires on it and looks something like this
View attachment 408241

Now if you bought a single wire switch that is small like the 2 wire one above then that is why the gauge is pegging

These are the two I bought and are on the motor now. Now that I see it they are OEM and according to the Mercury website they are the correct parts...Unless I made a mistake. I questioned the shape difference of the "can" shape you posted and the merc website parts guy told me they changed shape. Was he wrong which is possible? Vin 0l072052

 

[alldodge]

The 805605A1 is a switch and opens when oil pressure comes up. If connected to a gauge it would peg it and once oil pressure builds it opens and gauge drops to zero

Merc part is 8M0068784 and is expensive

Sierra is 18-5899

 

[alldodge]

The switch you bought would work if attached to alarm circuit

 

[Bt Doctur]

the no oil pressure switch is wired to the alarm and will sound with motor off and silence when oil pressure is present has only 1 wire
The fuel pump pressure switch looks like the one in the pic with 2 wires
All others are fitted with plugs not wires

 

[pae0332]

technically there are 3 oil switches, one for the alarm, one for the gauge and one for the fuel pump. #'s 7,11 & 13
7 & 11 are on the side of the block by the oil filter and 13 is on top by the distributor.

 

[jonny rotten]

the no oil pressure switch is wired to the alarm and will sound with motor off and silence when oil pressure is present has only 1 wire
The fuel pump pressure switch looks like the one in the pic with 2 wires
All others are fitted with plugs not wires

The alarm with key on/engine off is by the distributor. If I pull off the wire the alarm stops. It also goes off when the engine starts. So I assume that's working correctly. Down by the oil filter The fuel pump switch has the 2 wires which is the only way to connect it. So I assume that's correct. The other switch which is the little one in the pic is on the tee with the fuel switch. That has a single blue wire. What has me puzzled is that switch is the exact same shape as the one by the distributor. Originally it had the large "can" type Alldodge posted. Merc said they changed shape and the little one was a correct replacement. Seems strange the replacement Alldodge shows is the same one that was originally on there, yet Merc says the little one is correct. Wondering if thats my issue

 

[jonny rotten]

The switch you bought would work if attached to alarm circuit

There is only one way to attach the switches. Single push on wire on switch by distributor. If I take take that wire off the KOEO alarm stops, fuel switch by oil filter has 2 spade connectors, and the other one in pic by the fuel switch has a blue push on wire. There are no other wires and no other way to hook them up. Theres no way to mess it up. How do I know if the one by the oil filter with a single blue wire is hooked up to the alarm circuit? Also I aasume the fuel switch with the 2 wires has nothing to do with the oil pressure gauge issue. Which of the other 2 switches would effect the oil pressure gauge? The one by the distributor or oil filter. I assume by the oil filter because I never touched the one by the distributor and it was working fine last year

 

[alldodge]

The other switch which is the little one in the pic is on the tee with the fuel switch. That has a single blue wire. What has me puzzled is that switch is the exact same shape as the one by the distributor. Originally it had the large "can" type Alldodge posted. Merc said they changed shape and the little one was a correct replacement. Seems strange the replacement Alldodge shows is the same one that was originally on there, yet Merc says the little one is correct. Wondering if thats my issue

Use item numbers it pic above to clarify which ones you are discussing

Item 11 are different variations

Item 13 is oil gauge sensor and may not look like the one I posted

How do I know if the one by the oil filter with a single blue wire is hooked up to the alarm circuit?

The one by the oil filter is not the switch for the alarm for 2 reasons. One it has a single blue wire and not a tan/blue wire. Two Merc uses boat standard industry colors for all circuits. The one by the oil filter with single Blue wire is for the gauge is NOT the alarm, it's the gauge sensor



In short you installed a switch for the gauge sensor by the oil filter

 

[pae0332]

There is only one way to attach the switches. Single push on wire on switch by distributor. If I take take that wire off the KOEO alarm stops, fuel switch by oil filter has 2 spade connectors, and the other one in pic by the fuel switch has a blue push on wire. There are no other wires and no other way to hook them up. Theres no way to mess it up. How do I know if the one by the oil filter with a single blue wire is hooked up to the alarm circuit? Also I aasume the fuel switch with the 2 wires has nothing to do with the oil pressure gauge issue. Which of the other 2 switches would effect the oil pressure gauge? The one by the distributor or oil filter. I assume by the oil filter because I never touched the one by the distributor and it was working fine last year

unplug the single wire by the oil filter, does the gauge stop reading high?
if so, you have a switch for a light, not gauge, those sensors work as on/off, like the alarm sensor. whereas the gauge one is a potentiometer.

 

[jonny rotten]

unplug the single wire by the oil filter, does the gauge stop reading high?
if so, you have a switch for a light, not gauge, those sensors work as on/off, like the alarm sensor. whereas the gauge one is a potentiometer.

Unplugging the wire does nothing. Stays pinned high with key on or off. Stays pinned low with engine running

 

[pae0332]

Unplugging the wire does nothing. Stays pinned high with key on or off. Stays pinned low with engine running

then you have a short circuit. disconnect the blue wire from the back of the oil pressure gauge, if it still pinned, replace the gauge
wait, it is pinned high with key on, engine off and key off?
then pins low with engine running?
was the alarm still ringing when you have the engine running or is that resolved?
if the alarm is still going off,, check the oil pressure with a manual pressure tester, you may have no oil pressure

 

[jonny rotten]

Use item numbers it pic above to clarify which ones you are discussing

Item 11 are different variations

Item 13 is oil gauge sensor and may not look like the one I posted


The one by the oil filter is not the switch for the alarm for 2 reasons. One it has a single blue wire and not a tan/blue wire. Two Merc uses boat standard industry colors for all circuits. The one by the oil filter with single Blue wire is for the gauge is NOT the alarm, it's the gauge sensor

View attachment 408249

In short you installed a switch for the gauge sensor by the oil filter

I think I figured this out. In post #10 the diagram shows 18,12, 11,13 as a tee assembly which I replaced the entire assembly. I bought 11 which is the part with the pigtails in my pic. Naturally I bought #13 which is on the tee. As it turns out 13 is the alarm by the distributor and the pic is wrong or I have a different configuration. What I needed was #7 waaaay over there in the diagram and nothing like the setup on my motor

 

[jonny rotten]

then you have a short circuit. disconnect the blue wire from the back of the oil pressure gauge, if it still pinned, replace the gauge
wait, it is pinned high with key on, engine off and key off?
then pins low with engine running?
was the alarm still ringing when you have the engine running or is that resolved?
if the alarm is still going off,, check the oil pressure with a manual pressure tester, you may have no oil pressure

I think I figured this out in post #17. Thanks for helping. If what I said seems wrong let me know

 

[jonny rotten]

I installed the Sierra 18-5899 sender alldodge recommended. Everything working good. Thats for the help all!!