62 Temperature Gauge

[Greg S]

temperature gauge greg s after restoring the dash cluster over the winter i cannot get the temp gauge to work the needle stays al the way to the right and does not move when the engine is warmed up i have checked all the connections and they are as they should be according to the aim manual i labeled the wires and put them back where they were labeled to belong the gauge worked perfectly before i restored the dash all other gauges work including fuel how can i troubleshoot this problem i have a voltmeter but am not sure how to use it i have also discovered that the dash lights controled by the headlight switch reostat do not work could i have a ground problem are the two problems related

[G B.]

Re: 62 Temperature Gauge

re temperature gauge jerry bramlett set your meter to read voltage disconnect the blue or green wire from the top of the engine temperature sending unit with the ignition key turned on the engine doesn't have to be running touch one meter lead to the disconnected wire terminal and the other to an engine chassis ground if you don't get a reading of volts move to the dash gauge and check the voltage at the two wire terminals on the back to locate the disconnect if you do have volts at the wire you can turn the key off to check the sender set your meter to read ohms resistance with the sender still screwed into the intake manifold touch one lead to the sender tip where the wire attaches and the other to the exposed threads on the side you should get about to ohms at ambient temperature if you get infinite resistance then the sender is faulty or not making a good ground with the engine please post your results or any questions you have about this procedure jerry

[Greg S.]

Re: 62 Temperature Gauge

re temperature gauge greg simon the sender wire reads volts the sender shows ohms what next are there any other tests to check the operation of the gauge

[G B.]

Re: 62 Temperature Gauge

re temperature gauge jerry bramlett great now warm the car up with the temp gauge wire disconnected from the sender when you feel the thermostat open by holding the upper radiator hose turn the engine off and check the resistance of the sender again it should have dropped to maybe ohms or so if it hasn't changed much since the cold check then the sender is bad if it has gone down check the resistance between the sender tip and the intake manifold you should get the same reading if the sender is well grounded to the intake if the hot sender has low resistance and gauge is still buried to the left then the dash gauge itself must be broken

[Ed Jennings]

Re: 62 Temperature Gauge

re temperature gauge ed jennings with the ignition switch on connect the sending unit terminal to ground it should read full scale all the way to the right if not see the above post

[Greg S.]

Re: 62 Temperature Gauge

re temperature gauge greg simon ed i am not sure i understand your instructions should i connect a jumper wire from the sender wire gauge terminal to a good ground do i need to disconnect the terminal wire from the gauge does this then send a full volts to the gauge how does the gauge measure temperature the higher the voltage the further the gauge moves to the right

[Ed Jennings]

Re: 62 Temperature Gauge

re temperature gauge ed jennings greg sorry i was in a hurry disconnect the wire from the sender at the sender turn the key on and the gauge should read full left empty now ground the sender wire to a known good ground like the engine block it should read full scale all the way to the right if not the gauge is bad and will have to be replaced or repaired recalibrated if it reads ok the sending unit is probably bad i say probably because you still have not eliminated the wire from the gauge to the sending unit you can do that by using a separate wire that you know is well grounded and touch it to the sender terminal of the gauge it's a bit more trouble but it eliminates a wire problem the sending unit is a variable ground device and the hotter it is the better a ground it makes this is somewhat simplistic if you have to replace the sending unit make sure you get one of the right resistance i believe an earlier post addressed this good luck email me if you need more info