TEMPRETURE GAUGE Fault diagnostics

[jpliddy]

hi all i am trying to find out how to find the fault with my non working temperature gauge i have swopped the gauge and the faults still there . heres my problem sometimes i turn on the ignition and the gauge never moves sometimes i turn on the ignition and the gauge goes straight to 11 o clock when cold all advice most welcome !

[skarpa]

My mate simply replaced the whole sensor and gauge using a £6 universal kit off ebay. Slightly longer than the original sensor. There was a bit of limescale to clear out to fit it. He mounted the new gauge in a spare hole on the dash.

I did see a supposedly original sensor on ebay too for about £6 I think

[ngoma]

What year is your car? It may be from the range that used the infamous Bosch "biodegradable" wiring. In that case, the wiring would be highly suspect. A good troubleshooting method would be to temporarily use a good length of wire between the sensor and the gauge.

[jpliddy]

hi ngoma what terminals woud i need to wire on the clock as there are 5 on the back of the clock and just 2 from the señsor auction block near front of the engine regards jim

[jpliddy]

its a 1995 year of manufacture

[v8volvo]

1995 would be new enough that it should not have the problematic wiring insulation I believe, although that doesn't mean it couldn't have a bad connection or chafed wire anyway.

Let's try to be systematic about how we troubleshoot this. I suggest starting from the front and going through the system piece by piece until we find the issue. First thing to check will be the sensor itself.

The sensor (sometimes also called a sender or sending unit) should be located near the front of the cylinder head, close to the glow plug for the #1 cylinder. I think you have seen it there before. Here are the first two questions:

1) Once you have found the location of the sensor, can you confirm if the sensor has ONE wire on it? Or does it have the later style sensor with a TWO wire connector?

2) Do you have access to a volt/ohm meter?

Depending on which style sensor and connector your car has, the first diagnostic step will be to look up the correct resistance values for the sensor on a cold and warm engine. Then you can test your sensor's actual resistance readings using an ohmmeter and see if your measurements are close enough to the required values.