Mystery Oil pressure switch '98 Serengeti 3706

[astrnmrtom]

I was recently chasing down a small oil leak and found a drop of oil hanging off the bottom of this switch that's Teed off the main oil pressure switch fitting. Does anyone know the specs for this switch, or what it might be for?

[CactusTwo]

If it has a single wire on it,someone replaces the sensor for either the dash or service bay oil pressure gauge. Each has their own sensor/ sender. I have replaces both mine with the appropriate sender. There are matching ones to the dash. ie" 0-100psi for the Datcon marked with Safari gauge, 0-80psi, 0-120psi for the VDO gauges

[astrnmrtom]

Thanks,

Yes, it has a single wire going to it.

I wasn't even thinking about the service bay gauge. I thought possibly an idiot light on the dash in addition to the oil gauge. My dash gauges are labeled MAGNUM and the oil gauge is 0-100. I'll have to look to see what brand the service bay gauge is. Now that you've jogged my memory about the service bay gauges, I remember one of them doesn't work, Now I'll have to check and see if it's the oil pressure gauge.

[CactusTwo]

Sorry mine say Magnum as well and they are Datcon brand gauges and senders/sensors. I got my replacement oil senders from NWRV Supply, about $15 but if you look elsewhere on line look up Datcon as the gauge and sender must match by name and gauge pressure. Look here for the part numbers https://c-a-i.net/DATspeedos.php. Search this site for speedos, tachs, all other gauges

[CactusTwo]

Scroll down to the bottom of the datcon page I have posted and click "go back" and all the gauges will pop up with part numbers and visuals less the Magnum word

[astrnmrtom]

Excellent! You've answered another age old question for me, and that's who made the gauges. Literally, as I pulled out on the road from the first campgound when starting our full time adventure, I noticed my Speedometer was suddently reading 15mph too slow. Couldn't figure out where to get a replacement, so I tried a simple caveman style repair. Pull the bezel, face, and the needle, and put the needle back on where it reads correctly. It took a couple tried to get it right, but it's worked fine ever since, and it's been 3 years and thousands of miles all over the US.

[TDJohn]

If that oil pressure switch does not operate one of the gauges, it is possible that it could be the signal switch that runs the engine hour meter, located in the service bay. Some Safari coaches did use a signal from an oil pressure switch to run the hour meter.

[CactusTwo]

I have traced my hourmeter wire back to the blue isolator in between the alternator and batteries and have a fused (5amp) connector on the center post. Note that hourmeters typically hook to either a pressure switch or ignition source and isolator is energized when alternator is running/ engine on!

[astrnmrtom]

Update,

After cleaning around the area and starting the engine, indeed this little switch is leaking. This time, when looking at the best way to get to this little stinker to replace it, I discovered there is another oil pressure sending unit, which makes for a total of three Teed off this port. The mystery switch is no loner a mystery. It's the NC switch that illuminates the "Low Oil Pressure" dash lamp. The only hour meter on my rig is for the generator. Now that the switch is disconnected, the light doesn't illuminate when the ignition is energized. The other two are sending units, one to the dash gauge, and one to the service bay.

Digging through my collection of old Safari files collected from online, I found a reference to the switch in the Dash Info document. It's a bad scan of of the drawing, so I can't make out the exact part number. It looks like Cole Hersee 1/8" NPT #(?) 0600(?) or 0620(?) The model numbers are blurry (2-7 PSI) The 0620 does match up with a Duralast PS620 from Autozone.

Looks like it's a common automotive oil idiot light switch, which as far as I can find, has an opening pressure of 3-5 PSI. The PS620 looks like it's used in a long list of vehicle applications across many manufacturers. There's a Duralast PS117 which appears the same except with a spade connector vs a threaded stud.

I found some references to the Duralast PS620 crossing with:
AcDelco 19106678 or U8002
Airtex 1S8058
BWD S4145
Carquest 53-33799
Harley Davidson 2655272

The PS620 isn't in stock, so I'll be ordering it and I'll give a final update.

Attached are photos of the switch. You can see it has oil in it and in one photo a dimple of oil seeping out the tiny vent hole, and the numbers stamped into the faces.

[CactusTwo]

There you go, my 1996 "1WM" 3126 Cat (with the 40 pin ECM) doesn't have that switch as I am sure that I have only "T" at the end as yours must be a 3126B series with a different serial number prefix. Good find, best of luck