XJ6 gauges problem,

Hi there jaglovers. I have an 84xjs. The oil pressure gauge is now continuously reading on the 100 (maximum reading) mark. It also reads 50 with the ignition turned on but engine not running. It did intermittently work a few days ago. Can anybody tell me how to test the sender and the gauge. I know the gauge has 3 copper terminals on it. The car is a 3.6 manual.

Are these the “barrel” gauges where the needle moves vertically up and down?

If so, I think the first thing I’d look at is to pull the instrument panel out (it’s easy) and check all the connections from the flexible circuit down into the gauges themselves. It involves some screws with threads that dig into a printed circuit panel on each gauge.

Yes, they are the barrel gauges Gilbert with the needle moving vertically.
I recently had the instrument cluster out and I did rescrew the three screws that
hold the gauge in. The gauge worked well the next day but now it’s as I mentioned in my post,sitting on 100. I have a couple of spare gauges which I pulled from an older instrument panel. Is there a way to test these out of the instrument cluster?

Hi Kirbert,

Thanks for replying to my post. I sent a reply to you on the Jaglovers website. Please accept my
apologies for mispelling your name.



I’m pretty sure there are three connections to each gauge. The first thing to do would be to check each of the three for continuity to the other two.

There are three connections on each gauge. The bottom one has “ALW” printed just near it. Does this mean “Active Live Wire” ? I put my multimeter on the beep setting and there was no beep between any of the three connections no matter in what combination I placed the probes. Does this mean it is definitely broken? Should there be continuity between any of the three terminals? I have a spare temperature gauge and this registers a beep between the ALW terminal and the middle one but not on the others.

Try a different gauge, one that works. All the gauges are the same except the voltmeter, they just have different scales painted on.

So does that mean you could use a water temperature gauge as an oil pressure
gauge and vice versa.

I believe so, although it’d look funny.

Unplug the sensor at the engine; gauge should stay at zero with ignition on. If gauge still goes mid scale or full scale, the problem is in the circuit board/gauge. Sensors can short or go out of calibration due to engine heat and vibration.
Circuit board connections and bad grounds usually affect multiple gauges and may change readings when dash illumination is on.

I have seen similar thing with failing sender. Also with 3.6.
Not sure about sender price, but picking the acutal working sender is an essential thing. There is plenty of “senders” showing only one true value (also known as pressure switch) due to XJS owners being concerned with dropping pressure on hot - as per official Jaguar bulletin.

There might be a grounding problem O my 94, the temp gauged pegged even when the car was cold. Ran a new ground from the flex board and things were fixed.

For the oil pressure sender, that was a spectacularly crappy “upgrade”. I think I still have one lying around somewhere. I can bung it on eBay for 99p if anyone is interested.

My car, which is a 3.6, the AJ6 engine has two oil pressure “senders”. A larger one closer to the front of the engine block and a smaller one just further back from that. According to my manual the the larger one is for the oil pressure gauge and the smaller one is a low oil warning light. Is that right?

Adrian. The v12 has two “senders” at the rear of the engine. One is a simple pressure switch that turns off the idiot light if oil pressure is above set point (i think 5 psi). If pressure falls below., the red warning light comes on. The other sender drives the pressure reading on the gauge.
The Jaguar “fix” was to cause the gauge sender to stay at middle of possible indicator range, regardless of actual pressure. Definitely a hokey fix

Hi Guys, I put a wire from the metal strip at the back of the instrument cluster
to a large metal bracket attached to the body of the car. My oil pressure gauge came to life. The gauge continued to work after driving around in the car all day, reading from about 40 in the max range to about 15 at idle. So hopefully this has solved the problem. A small win in the battle against the “Prince of Darkness”. But have I won the war??? I just like to thank you all for your help with this. Where I live Auto Electricians either refuse or are very reluctant to work on Jaguars.