742B temp gauge removal

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My temp gauge hasn't worked since I have owned this machine (9 yrs). Before replacing the sending unit, I need to access the gauge to see if it is the problem, or if there are bad electrical connections. How do I remove / open the plastic housing which contains the gauges in the upper right corner of the cab ? I have removed the big screw which attaches that housing to the front of the cab, but it is still firmly attached. I don't want to start prying and break something. What next ?

 

[jsenicka]

There is a screw in each corner of the panel. Two on top and one on bottom

 

[[email protected]]

There is a screw in each corner of the panel. Two on top and one on bottom

Found the screws hidden behind the headlight. There is no sign of any bad connection, so now to test the gauge. With the ignition switch on, I have power to the gauge (orange wires) when grounded to the cab or to the sending unit (purple/white). From this point how do I determine if the problem is the gauge or the sending unit?

 

[PEVO]

Found the screws hidden behind the headlight. There is no sign of any bad connection, so now to test the gauge. With the ignition switch on, I have power to the gauge (orange wires) when grounded to the cab or to the sending unit (purple/white). From this point how do I determine if the problem is the gauge or the sending unit?

Like you said orange is hot, purple /white is sending unit wire. touching it to ground should move the gauge to full hot. Sending unit on engine works as rheostat. Cold..its off.(open to ground) The hotter it gets it gradually allows the current for the gauge to find ground. Overheated sender should fully ground the gauge via the sending wire(purple/white). Sorry i didnt describe in proper terms...but in a nutshell that the way it works. Idiot lights work the same...however here senders are just a pressure or temperature activated switch to ground...either on or off

 

[[email protected]]

Like you said orange is hot, purple /white is sending unit wire. touching it to ground should move the gauge to full hot. Sending unit on engine works as rheostat. Cold..its off.(open to ground) The hotter it gets it gradually allows the current for the gauge to find ground. Overheated sender should fully ground the gauge via the sending wire(purple/white). Sorry i didnt describe in proper terms...but in a nutshell that the way it works. Idiot lights work the same...however here senders are just a pressure or temperature activated switch to ground...either on or off

It works just like you said. Dealer had a sending unit in stock, and temp gauge actually works now !