no power to oil gauge, 4.0L

[a bum with money]

recently my oil gauge stop working. no matter what I do, sender wire disconnected, wire grounded, the gauge does not move. it stays @ 0. all the other gauges are still working, as far as I can tell it's only the oil gauge that's affected.

using a ohm meter set at 200 with key off:

1. .4 ohms @ sender wire (disconnected)

2. 30.+/-  ohms @ sender itself (wire disconnected)

3. .4  ohms @ sender w/sender wire attached

4. gauge does not move

 

with key in run position:

1. 34.+/- @ sender wire (disconnected)

2.  same as #2 above

3.  34.+/- ohms w/sender wire connected

4. gauge does not move

 

with engine running:

1. 34.+/- ohms does not change with RPMs

2. gauge does not move

 

my thinking is that the sender wire is broken or grounded some how or the gauge is broken. I'm not quite sure as to how to trace this problem. start at gauge or at sender? about 4 years ago I upgraded to full gauges and installed a new sender w/gauges, worked great until recently. there hasn't been any recent work done, and I still drive the rig, oil is topped off, still have good oil pressure.

 

1988 MJ, 4.0L, AT, 2WD 127k miles

 

[jdog]

Sounds like the gauge went bad

[a bum with money]

On 8/4/2021 at 10:38 AM, jdog said:

Sounds like the gauge went bad

just to confirm your statement I pulled the instrument assy. out to test the gauge itself. looking at a wiring dia. the ignition side powers all the gauges and the other side of said gauge goes to the sender it is connected to. regarding the oil gauge with the key in the run position I get 10.9v but on the sender side I get .25v. shouldn't it be the same voltage on the sender side too? when I tested  the water gauge I had the same voltage on both sides. if the gauge is bad will an HO(94) oil gauge work in its place?

[jdog]

Yep gauge is bad,  I am not sure, but I don't see why not