Temp Guage Stopped Working

[mostly_water]

My temperature guage suddenly stopped working this week, pegged at the cold end of the scale. A quick look didn't turn up anything obviously disconnected. I can live without it, but will the guage malfunction influence my ECM's settings and self-adjustments? If so, I should try a little harder to fix it soon.

Thanks.

[Irk]

I'm not sure if it will affect your ECM but I'm guessing it probably does. Do you have a haynes repair manual for the Metro, definite need if your going to be fixing your own car, If you don't I scanned the page from the manual that will fix your temp guage problem. Check your fuses first, you might get lucky and its just a bad fuse. Its probably your Coolant Temp Sending Unit though.

[GM Line Rat]

Originally Posted by Irk

I'm not sure if it will affect your ECM but I'm guessing it probably does.

No, this sending unit does not have any control on the ECM. This sending unit is for the dash gauge only. The "Engine Coolant Temp sensor" that is mounted in the side of the throttle body is the one that sends a signal to the ECM (Pic 9.3B). Just follow the instructions in section 9 of the scanned page posted to diagnose the problem.....The sender unit you want is the one with arrow in picture 9.3A.

[Irk]

Originally Posted by GM Line Rat

No, this sending unit does not have any control on the ECM. This sending unit is for the dash gauge only. The "Engine Coolant Temp sensor" that is mounted in the side of the throttle body is the one that sends a signal to the ECM (Pic 9.3B). Just follow the instructions in section 9 of the scanned page posted to diagnose the problem.....The sender unit you want is the one with arrow in picture 9.3A.

Don't you mean 9.3B

[GM Line Rat]

Originally Posted by Irk

Don't you mean 9.3B

No....Not on my 94 Geo Metro. In the pic below, #3 Is the "Engine Coolant Temperature Sending Unit".....The sending unit is for the Temp GAUGE in the dash and is located in the Goose neck for the radiator hose.....#11 in the pic is the "Engine Coolant Temperature Sensor and is located in the side of the Throttle Body.....This is the sensor for the ECM Computer. However, since there were several different variations of these cars (Standard Emmisions, Upgraded Emmisions, Autotrans, Manual Trans, With AC, No AC).....The pic in the Haynes book could be correct for His Year, Make and model of Metro?

[mostly_water]

Over the weekend, I unplugged every electrical connection and fuse under the hood and cleaned each one. It's surprising how many connections there are. I would say about 20-25% had some degree of corrosion or dirt on the contacts, again surprising. Of course, the car wouldn't start after that - but I quickly found two connections that failed to reconnect adequately. The temperature gauge is working once again, I can't comment on which connection did the trick. It may be my imagination, but the car seems to idle cold better than before - but I do have a vivid imagination. Thanks to everyone for the helpful replies, you guys are great!