Huston, we have a problem.

[xj_dummy]

Ok, I changed out my gauge cluster on my 86, 2.5L, for an 1988 XJ 4.0 cluster. The tach, fuel and speedometer works.

BUT the volt meter, water and the oil pressure gauge doesn't. I did change out my old oil pressure sending idiot lite unit for a gauge unit instead, and still no worky.

Should I have gotten a O.P. unit for an 1988 instead of a 1986?

Help!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[HOrnbrod]

Ok, I changed out my guage gluster on my 86, 2.5L, for an 1988 XJ 4.0 cluster. The tach, fuel and spedometer works.

BUT the volt meter, water and the oil pressure guage dosent. I did change out my old oil pressure sending idiot lite unit for a gauge unit instead, and still no worky.

Should I have gotten a O.P. unit for an 1988 insted of a 1986?

Help!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

Should work, but you'll also need a new temp sensor to replace the existing temp switch you have in there now. Try this and report back. Any movement at all on the no-workie gauges at all? :cheers:

[Eagle]

The temp sensor and the oil pressure sensor for the gauges would be the same for an 86 as for an 88. That's not the problem.

 

Begin by testing the gauges themselves. You'll need an assistant.

 

For either gauge, the sensors are variable resistors. The range is zero ohms to 88 ohms. Zero ohms, of course, is no resistance, or a short circuit. So, as a rough "go / no go" test, you turn on the ignition (the engine can be running, but be careful where you put your hands. The engine does not NEED to be running, but the ignition has to be on.) Take the wire off one of the sensors. You now have an open circuit ==> infinite resistance. The needle on the gauge should swing all the way to the right. Now find a clean, dry place on the engine block and touch the wire to the block to ground it. You now have zero resistance. The needle on the gauge should swing to the opposite end of the scale.

 

Repeat for the other gauge.

 

If the gauge fails this simple test, you have a faulty gauge, or a break in the wiring between the gauge and the sensor. If you know the idiot lights worked before, the wiring should be good. Problem is, you have no way of knowing whether or not the idiot lights actually worked, because the start-up test only checks the bulb, it can't check the circuit.

 

Let us know what you find.

[xj_dummy]

OK, I got the new temp switch in and it works but the oil pressure gage doesn't nor the amp gage.

I tried the open circuit test for the oil and temp. Temp worked but oil pres. didn't.

Where does the gage for the alternator gets it reading? Directly from the ALT or another switch?

Thanks for your Help.

mike

[Eagle]

It isn't an alternator gauge. It's a voltage gauge. It reads the voltage in the wiring at the instrument panel. Occasionally, if there's corrosions in various connections, the gauge reads low but the alternator is putting out the correct voltage if you test at the battery. I have that in my '88.

 

Don't know why yours would be completely dead. Put a known 12-volt source directly to the two posts on the back of the gauge and see if it gives a reading.

[xj_dummy]

Well I fixed it, I went to the wrecking yard and found an 85 Cherokee with a 2.5 5speed. And grabbed that speedo cluster and clock. Plugged the new cluster in and everything works, go figure. Also the clock works too.

Now I have to return the other cluster back to the wrecking yard and get credit for it, no cash but I think that I might find something that I don't need. :eek: