[monzter]

I have Auto meter gauges in my car, and the Water temparture gauge (Ultra-Lite) is now stuck in the five o clock, even if i switch the main switch off.
The gauge is the electric one, does any one now what my problem is ?

Best regards

 

[ericnova72]

Is the needle position at 5 o'clock the max temperature on the scale?? If it is, the wire from the sending unit to the gauge has become grounded(shorted to ground) or the sending unit has gone bad causing the max scale reading.

These electric gauges are just simple resistance reading gauges. The less resistance to power passing through them, the higher they read. The sending unit is a temperature variable resistor, allowing no power to pass through when cold(zero or not yet in range on gauge face) and gradually allowing more ground (reading on gauge face) as they heat up, shorted completely to ground gives an maxed out reading. It won't return to zero as the needle freezes when power is removed, and is still fully grounded when you return power to it.

 

[monzter]

http://www.summitracing.com/parts/ATM-4437/ - This is the gauge, and it goes right where the dot at the right is. And just stays there. So it would be a bad ground ?

Best regards.

 

[ericnova72]

http://www.summitracing.com/parts/ATM-4437/ - This is the gauge, and it goes right where the dot at the right is. And just stays there. So it would be a bad ground ?

Best regards.

Yes, that would be what I suspect first, it isn't really a bad ground, the wire from the gauge to the sending unit has become shorted to ground(i.e. it is pinched or melted/wore through somewhere and is grounding the gauge to produce the over-the scale reading) or the sending unit has failed and providing a full ground path resulting in the over hot reading. The gauge reads resistance to ground through the sending unit, and right now it appears to be reading full ground with no resistance, so the sending unit wire and sending unit are prime suspects. Remove the wire from the sending unit , keep it from touching a ground, and re-power the gauge to see if the sender is bad. It should go back to zero/bottom of temp scale, if not remove sender wire from back of gauge and try again.

There is also the possibility the gauge has failed.

 

[302 Z28]

Have you tried removing all connections to the gage? I had one do the same thing after I accidentally shorted it while working on my console. I ordered another one and when I went to take the shorted one out to install the new one the needle returned to normal and is working fine. Now I have a new replacement just sitting on the shelf.

Vince

 

[monzter]

What is the best way to check if it is shorted to ground ? Trace all the wires with check-light ? or is there a better way ?

 

[hilltopredneck]

AutoMeter

If this is not to late, I have AutoMeter gauges, I had a problem with it reading 250, but using an infrared laser temp reader all was normal temp. I was using the cheap p.o.s. that works good for idiot lights.
I'm told that the gauges and sensors are matched. All is fine now.
Are you using the stock or Autometer?

 

[monzter]

I have Auto meter ultra lite gauges, and my problem was that the gauge never red anything, it was just at the 300°F mark !!! but I have fixed the problem for now.

Thanks guys for the advices, i appreciate the help really much.