I think that light at the left end of the instrument cluster is wired into the oil pressure circuit. Once a certain voltage is reached it illuminates the light to catch your attention much in the way that the fuel guage lights up when your very close to "E".

Ill look at wiring diagrams but im sure its hooked into the same circuit as the guage and the same sending unit

 

So it'd be the gauge unit i'd need then, not the "light" version, right?

 

yeah the guage unit.. I havent come accross and xj that didnt have the guage for oil presure.. and like I said the sending unit operates both guage and light from the same unit

 

So if I used silicon sealer on the threads of the sending unit would that cause the gauge to peg all the way to the right? THAT would explain why I have tryed 2 gauges & 2 sending units & still the gauge stays peged to the right.

thanks

 

your not supposed to use anything but motor oil to seal the sending unit. it has to ground against the threads. with a sealer or teflon on it you wont get the proper resistand and it may just cause it to peg one way or the other...

 

My 96 XJ has no gauge. I have the se model, which has virtually no options. I just have the warning light system. My cluster is a big ol' gas gauge and equally big speedo. The sending units for each type of system are different, I have been putting together the stuff to swap out for the full cluster, and it requires swapping my sending units out to the gauge type.

 

i just swapped the cluster on mine to the guage type, and the 2 sending units are different. its 26.99 at advance auto parts. I havent swapped that one out yet due to the price. i might just stop at the JY this weekend and pick one up for $5. If your near a yard you could do the same and save some cash

 

I was refering to having the guage and the warning light on the left of the cluster.. As far as I can tell from wiring diagrams I have looked at, albeit the infamous haynes manual and I still have to check the service manual I have, they are connected and use the same sending unit. The guage is a resistive type where the pressure pushes on a diaphram changing the resistence of the circuit much like the sensor in the thermostat housing on the newer XJ's where as for the "idiot" light its just a switch that is has a diaphram too but has a predetermined pressure to where the switch will make or close the circuit which is why the idiot light is on when your starting the rig and goes off after the pressure builds to open the circuit or contacts.

 

Well DUH you need continuity LOL I removed & cleaned the sender. Gauge still pegged to the right

 

Where are you guys getting your sending units so cheap at? The local auto parts store quoted me almost $80 for a new one for my '96 b/c they said they dont stock them and are only special order.

 

You got to deal with a local parts store. The chain stores are killing the old school neighborhood auto parts store. United Auto parts in Venice Fla (off the bypass) is my #1 choice.

I have at least one should be good oil press sending unit for sale. $20 + shipping

 

if the guage is pegging it is not properly grounded or not grounded. if pegged the dash gauge is working, but not the wire, and or sending unit. did you get the same sending unit, they make a normally open, and a normally closed, and the do work opposite of each other. find a mechanic that will loan you a good liquid filled guage, and hose with 1/8 male pipe thread and get an acual reading of the oil pressure, and dont trust the cheap sending unit they may have sold you. unhook the wire and touch it to the filter housing to ground it, if i am correct the dash

 

The dash what??? what should the gauge do if the wire is grounded?

 

normally when you ground the wire, the guage in the dash peg's itself, but not sure that's the case with a jeep, as i stated. it may work backwards. just trying to give some troubleshooting help, hope i didnt mess you up.

 

Well I went to the parts house to make sure they sold me the correct part & yes it is the correct part so I am looking at either a 2nd bad gauge OR a wire that is grounded. I am going to go to the JY & get a 3rd cluster & maybe it will work. With the dash apart I will check continuity of the wire.