Temperature gauge not working at all

[MoparDan]

Thursday I loaned The Cherry Bomb to a friend to pick up his wife from the hospital...anyways with no sign of anything wrong the radiator blew, the temperature gauge wasn't showing hot or anything, there was smoke all of the sudden, in addition to the radiator we replaced both the thermostat and the temperature sending unit. Now the temp gauge isn't working at all, just stays on cold, the engine seems to be running normal, the heat blows hot, so it couldn't be running too cold, made a couple short trips, the gauge just stays cold. Yes I checked the fuse looks fine and the fuel gauge is working, theres only one fuse for the gauges right? Whats going on? defective sending unit? bad gauge? (the alternator gauge hasn't worked in a while if that means anything)

 

[Sub03]

You can test the gauge by grounding the wire going to the sending unit. The gauge should move all the way towards hot position.
If the gauge moves when grounded the culprit is the sending unit or maybe bad connection in the plug at end of wire.

I've experienced my temperature gauge not moving a couple of times, cleaning the plug and giving it a dash of WD40 did the trick every time.

 

[Rustyroger]

I had trouble with the gauges on my Fifth Avenue, it was the posts on the back of the circuit board for the multi-plug connecter not properly conncting with the board. Patience and some time with a soldering iron fixed it. But try the simple and obvious stuff first.

Roger.

 

[Aspen500]

You've probably done this already but, double check the coolant level, just to be sure. If there's an air pocket where the sender is, the gauge will read cold. If the heater works, it's most likely OK though. As mentioned, make sure the connector terminal is clean and tight. It can be squeezed slightly with a pliers if it's loose. Then again, it could be the new sender is bad right out of the box. If it sayes China on it, even bigger chance. The quality of parts store parts is going downhill fast.

The alternator gauge should read center 90% of the time. If the battery is good and the alternator is working correctly, the alternator is charging the battery at the same rate as the electrical load is discharging it. Cars run off the battery, the alternator is really a battery maintainer. That's why a weak battery will shorten the life of the alternator quite a bit. The amp gauge is basically a useless thing. A volt gauge is a lot better. Before they added a shunt to the circuit, all the current load the car used went through the gauge and many a Mopar burned to the ground when the connections got bad at the gauge, overheated and started on fire. Not much of a worry with the shunt. Think that started in 1975 or 1976(?).

 

[MoparDan]

How do I ground the sending unit wire?

 

[MoparDan]

BTW the plug feels tight on the sending unit

 

[MoparDan]

BTW the plug feels tight on the sending unit

 

[MoparDan]

BTW the plug feels tight on the sending unit

 

[Sub03]

How do I ground the sending unit wire?

Remove the plug on sending unit and connect it to a clean, not painted area on the engine.
I used a small screwdriver, put the end of it in in the plug and held (the metal part) against the water pump.

Get a friend to turn on the ignition and watch for movement on the temperature gauge.

 

[MoparDan]

Ok thanks

 

[MoparDan]

Ok, I don't have my handy right now so I used a wire, put one in the plug and the other end I touched to one of the alternator bolts: the temp gauge moved almost to the middle (not all the way to the H)

 

[Rustyroger]

Does the fuel gauge work?. If so I think the problem lies in the gauge itself or part of the pcb circuit for the gauge. If all the gauges aren't working properly could be a faulty voltage stabiliser. The one on the instument panel, not the charging circuit.

Roger.

 

[UNKIE]

I hope this helps

 

[UNKIE]

If I and the shop were still there I would have seen if you could have come by Massy Motors by the sea. Next door to the Harley shop or my house in Deltona. But them days are gone man I really liked working there I worked in the back shop with a fella from WVa. Now I'm in MD working on a 78 Plymouth Caravelle that as soon as one part is fixed you find something else is wrong. But what the heck it's something to do and helps me stay on my toes.