A few days ago my 1997 J30 dashboard temperature gauge stays at zero even after the car has run for a while. The car runs perfectly fine though.
I've always felt comfortable having a temp gauge but is it really necessary, considering other dashboard lights which might warn of overheating?
I'm not sure if the problem is the gauge or the sending sensor. If it's the sensor, where is it on the 97?

I'm not sure if this is relevant but the problem might have started after by alarm went off. I detached the battery cable and put it back on
but the alarm went on again. I did this several times until I opened the trunk closed it and the alarm went off. I'm just wondering if a
battery surge might have caused the temp gauge problem.

Thanks for any help,
Len

Like a lot of '70~'90's Nissan products, your J has separate temp sensors for the ECM and the dash gauge. Chances are the sensor is bad, since the gauges usually read high when they fail. The gauge transmitter will be a 1-wire sensor with a BLK/RED wire located down low on the left-front of the engine. Grounding that wire should make the gauge go full scale. If it does, the sensor is bad. If it doesn't, then you have an open in the wiring or a bad gauge.

Thanks for such a quick response. I'm not quite sure about the sensor's location so I took a photo. These two sensors are near the top front of the engine. Can I assume that the smaller, closer one is the one in question. If I'm all wrong about the location, how about some more clues. Thanks Bud.

You're most welcome. My bad, I misread the harness diagram for the location. Check the wire color on the nearer one to make sure, if it's BLK/RED then that's it. The base is grounded into the coolant manifold, so just pop the connector loose and jump it to the base to test it. If the gauge pegs then the sensor is shot.

I wasn't able to pull the cap off the sensor which seemed to be fused to it. I just don't have the confidence to muscle it.
I was also leery about cutting the tape to see the color of the wire. Both the sensors have their wires taped in one bundle.
I guess that I'll have my mechanic deal with it. At least with your help I can discuss the problem intelligently with him.
Thanks for your help,
Len

You were right. The temperature sending sensor was bad. After replacement, the gauge works properly.
Len

Glad you got it working. Happy motoring!