Reading all this oil talk (I don't think I've ever seen a vehicle forum as obsessed with oil as much as Disco owners) has made me pay a bit more attention to my dash at startup.

Interestingly, I have 3 idiot lights that are out: Oil, Active Cornering, and the Air Suspension.

Since I don't have the air suspension or active cornering, that's to be expected; however, I do have an engine with oil, so I'm pretty curious as to why the oil light -out of all the others- does not light on at startup?

Anyone experience this before? If it's the bulb, it looks like a pain to get in there to change..

 

does it come on when the key is in the number 1 position with all the rest of the lights? there should be about a dozen light that come on when you first turn the key.

 

Nope. All the lights come on and then go out after their checks (except the battery of course, it stays on like it should until the engine is running).

I have seen every light flash and blink on my dash except the ACE, Air Suspension, and the Oil Light. The first two I believe were never hooked up. The last one stinks of "foul play"; however, the engine runs really smooth and quiet, I don't think I have an oil issue.

 

you should put a pressure gauge on it to see what your pressures are though,
if it was disconnected it must have been done for a reason.

 

Good idea, although I don't have one handy. Not 100% sure if it was disconnected or not. Anyway to check without ripping the dash apart?

I do have quick access to an OBDII scanner, I have no check engine light on now. When the oil light is in trouble does it throw a code that can be read/stored?

 

No. The oil sender does not report to the ECU. It is a simple switch and located near the filter. I also believe it is not part of the 3 second bulb test. If key is turned on, but not cranked, it would not time out. It should stay on until switch reaches like 7 PSI. As mentioned if disabled, there could be a reason. Attached is photo of location, C0187. If unplugged, shorting between the pins should turn on the light once ignition is switched on. Sensors can fail of course. With engine stopped, sensor should show a short when read by an ohm meter.

The sensor is unscrewed to mount an oil PSI test gauge, parts stores may rent/loan them. I bought one from Harbor Freight. You'll need an adapter that matches the switch threads.

As for getting into the dash, or finding the right electrical connector, the RAVE is a set of shop and electrical manuals that will show you all of that.

 

Just take your cluster apart and see if there is black tape in there or something. Or you might be really unlucky and the PO may have ripped the LED off the circuitry (as was the case with mine and the three amigos), or the light could just be bad (rare, but could happen). Either way, taking the cluster apart is really easy. 10 minute job and then you'll have a good idea of where to start looking.

 

Thanks everyone. I'll give it a look over when I get some spare time this weekend and report. I'm starting to lean towards a bad sensor or with the connection back to the dash. I'll check that angle first.

My previous owner kept meticulous records of his service (most being done at Bill's Great Basin Rover shop, one of the perks about being in Utah), and judging by the Carfax of the VIN, the two owners before him also took the vehicle to reputable shops and kept records.

Obviously anything can happen, but it really doesn't pass the smell test to me to have a clean '99 with under 100k miles, dealer/shop serviced its entire life all of a sudden have an oil switch tampered with. I guess it could have happened somewhere along the line, but I'm hoping it's something a bit less sinister.

Unless, of course, it was one of the oil change shops who did it along the car's past. I don't think I've been to a quick lube that'd I'd trust 100%...

 

I could be wrong, god know I have been it the past. But I believe the switch makes ground so if were just off like fell off your light should be on all the time?

 

Finally an update:

Looked around the front of the engine while swapping the 15-40 for some 5-30 winter oil and noticed a connector was disconnected. Reconnected (it was a single white wire that slid onto a spade-type connection, nothing fancy or locking mechanism at all).

Oil idiot light works like a champ now.