71’ Dart temp gauge stopped working

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RonsSwinger

RonsSwinger

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Hello Mopar brothers and sisters. during a drive recently my temp gauge stopped working. I ran my lead wire from the sensor to ground and the gauge didn’t move. I am told it is most likely a damaged wire or disconnected wire. Having said that, I recently changed out my headlight switch and it is possible that I loosened something in the process. I have no idea where the sending unit attaches to the gauge (or dash) to look for a loose connection. I watched a video on removing the dash panel and it requires dropping the steering wheel in order for the dash to come out (not an option). Does anyone have the ability to describe the wire to the gauge (I traced the wire to the firewall and it is fine) or even yet Pictures (for dummies) of the rear of the gauge and connections. Thanks in advance Ron D
 
I'm not sure what year yours is but on my 71 the wire harness connection to the gauge cluster is a round connector which pushes onto a ring of pins which are soldered onto the back of the gauge circuit board. If you are familiar with old vacuum tubes, it looks like that type of a connector. I ended up replacing my gauges for a bunch of reasons, one of which was that a couple of these pins had broken off the back of the circuit board. That being said, I did re-solder them and that did fix the problem related to a couple bad gauges. Perhaps this is what you have going on? Unfortunately, the only way to really get to any of that is to remove the bolts that hold the steering column to the dash and let it lower an inch or so. You will also have to reach up and disconnect the speedometer cable. Lowering the steering column is not hard at all and I have done it several times. Just be careful to put all the parts back correctly. There are white nylon pads that serve the purpose of allowing the column to collapse and in my case someone over the years had the whole system messed up and I had to purchase them to put it back to original design but it is not a big deal.

Installing new gauges has the advantage of switching over to an electronic pulse generator for the speedometer and thus eliminating the cable. Also, I'm not a fan of the amp meter that many of these models had since it seems like a fire hazard to me. If my car had the rally gauges I would have kept it original though but it had the economy cheapo dash.
 
Temp senders do just up and die without firing a warning shot. With the wire disconnected from the sender and engine warm an ohms meter should show some continuity between top contact and ground if the sender is good. If it shows open/no continuity, it died.
 
If you don't have a service manual go over to MyMopar and download one for free. Also there in the wiring section are aftermarket, two page wiring diagrams. I used those "some" but mostly the OEM ones in the service manual.

the temp sender wire is simple. The connector on the sender end can fail internally. The wire passes through the bulkhead connector, and that can fail. The wire then goes up to the PC board harness connector and that is a point of failure. I would not call these "probable" but certainly possible.

Does the fuel gauge work? That shoes that the instrument limiter /regulator is working if so.

The "path" and trouble spots in addition to above, are the harness pins on the PC board can come loos from the traces. The gauge studs can lose connection at the "fake" nuts on the gauges and of course the gauges can fail.

If the fuel gauge is not working, suspect the IVR and related connections.
 
RonsSwinger said:
IVR ?
Click to expand...
Instrument Voltage Regulator. On standard clusters it plugs into the cluster PC board, and operates the fuel/ temp gauge. With Ralley clusters, it is located IN the fuel gauge and operates it plus the oil and temp gauges
 
RonsSwinger said:
Thank you. Fuel gauge is working
Click to expand...
67Dart273 said:
If you don't have a service manual go over to MyMopar and download one for free. Also there in the wiring section are aftermarket, two page wiring diagrams. I used those "some" but mostly the OEM ones in the service manual.

the temp sender wire is simple. The connector on the sender end can fail internally. The wire passes through the bulkhead connector, and that can fail. The wire then goes up to the PC board harness connector and that is a point of failure. I would not call these "probable" but certainly possible.

Does the fuel gauge work? That shoes that the instrument limiter /regulator is working if so.

The "path" and trouble spots in addition to above, are the harness pins on the PC board can come loos from the traces. The gauge studs can lose connection at the "fake" nuts on the gauges and of course the gauges can fail.

If the fuel gauge is not working, suspect the IVR and related connections.
Click to expand...
I found the manual on myMopar and downloaded it. Thanks for the tip. It will definitely be useful down the road.
 
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