Hey guys
This thread should be a "how to" rather than a "what to do" thread which should help new people ot understand things. If my stuff is incorrect please feel free to make it clear! I am also pretty new to this stuff so many things might be incorrect.
Before you go troubleshooting make sure to check the fuses first! Also disconnect the battery if you're doing stuff with the wires.
I have the common problem that both, my temp gauge and fuel gauge dont work. We've found out in another thread that the first part to check is the IVR. If the IVR fails, both gauges won't work anymore. We've also found out that if one gauge breaks the other gauge won't work either (interrupted circuit). If the IVR is alright but the gauges still won't move, we have to check the gauges and/or the sender of each gauge.
To see if the gauge is alright, we can bench test it or ground the sender wire. Because I didn't want to remove the cluster once again, and to check the wiring itself aswell, I tried grounding the sender wires.
Now in my car ('74 Valiant 225 Slant Six), both gauges seem not to work but I have a new upgraded circuit board with a built in IVR, so the problem is either the gauges, the senders or the wiring itself. Last time the car was running I have had the old circuit board installed which had a loose IVR connection which might have caused problems with the temp gauge. Even tho I've installed the new upgraded circuit board, the fuel gauge still won't move so I have tried to ground the wires. And how I mentioned before, please correct me if I did something wrong.
I then started with grounding them to see if the gauges move. I have made a wire with two clamps on it to connect it temporarly and then turn the ignition key to see if the gauge moves. With clamps the connection is better aswell than just wave around with some wire by hand.
I've grounded the temp sender wire to the limiter housing which is grounded to the body. Another way is to ground the temp sender wire to the engine ground which is the strap from the firewall to the engine.
Some A-Bodies have a ground strap on the back of the car, between the bumper and gas tank. Mine didn't have that strap (I have no idea why). I grounded the fuel sender to the tank straps underneath instead because it was the only bare metal i could find in that area which is somehow connected to the body.
First I grounded the temp gauge, turned the ignition key and it moved slowly, but it moved. I then grounded the fuel gauge and it moved much quicker. Both gauges moved, so the gauges and the wiring should be fine. The fuel gauge still doesn't move when the connector is plugged on the sending unit, so I assume there's a problem with the sending unit itself.
To see if the temp gauge is working now, I'd have to go for a test drive and warm up the engine. If the temp gauge won't move either, there might be a problem on the temp sender aswell.
That's the condition of the fuel sending unit. Quite crispy with the undercoat, mmmh. I have no idea what the previous owner smoked. The installed temp sender is a replacement, SMP TS17.
BTW, if you want to buy the upgraded circuit board aswell, here's the link: Instrument Cluster Circuit Board with Built in Limiter 1972 - 1976 Duster Valiant Dart A-Body (not sponsored).
Here are two videos where I found out how to ground and test the gauges -----
This thread should be a "how to" rather than a "what to do" thread which should help new people ot understand things. If my stuff is incorrect please feel free to make it clear! I am also pretty new to this stuff so many things might be incorrect.
Before you go troubleshooting make sure to check the fuses first! Also disconnect the battery if you're doing stuff with the wires.
I have the common problem that both, my temp gauge and fuel gauge dont work. We've found out in another thread that the first part to check is the IVR. If the IVR fails, both gauges won't work anymore. We've also found out that if one gauge breaks the other gauge won't work either (interrupted circuit). If the IVR is alright but the gauges still won't move, we have to check the gauges and/or the sender of each gauge.
To see if the gauge is alright, we can bench test it or ground the sender wire. Because I didn't want to remove the cluster once again, and to check the wiring itself aswell, I tried grounding the sender wires.
Now in my car ('74 Valiant 225 Slant Six), both gauges seem not to work but I have a new upgraded circuit board with a built in IVR, so the problem is either the gauges, the senders or the wiring itself. Last time the car was running I have had the old circuit board installed which had a loose IVR connection which might have caused problems with the temp gauge. Even tho I've installed the new upgraded circuit board, the fuel gauge still won't move so I have tried to ground the wires. And how I mentioned before, please correct me if I did something wrong.
I then started with grounding them to see if the gauges move. I have made a wire with two clamps on it to connect it temporarly and then turn the ignition key to see if the gauge moves. With clamps the connection is better aswell than just wave around with some wire by hand.
I've grounded the temp sender wire to the limiter housing which is grounded to the body. Another way is to ground the temp sender wire to the engine ground which is the strap from the firewall to the engine.
Some A-Bodies have a ground strap on the back of the car, between the bumper and gas tank. Mine didn't have that strap (I have no idea why). I grounded the fuel sender to the tank straps underneath instead because it was the only bare metal i could find in that area which is somehow connected to the body.
First I grounded the temp gauge, turned the ignition key and it moved slowly, but it moved. I then grounded the fuel gauge and it moved much quicker. Both gauges moved, so the gauges and the wiring should be fine. The fuel gauge still doesn't move when the connector is plugged on the sending unit, so I assume there's a problem with the sending unit itself.
To see if the temp gauge is working now, I'd have to go for a test drive and warm up the engine. If the temp gauge won't move either, there might be a problem on the temp sender aswell.
That's the condition of the fuel sending unit. Quite crispy with the undercoat, mmmh. I have no idea what the previous owner smoked. The installed temp sender is a replacement, SMP TS17.
BTW, if you want to buy the upgraded circuit board aswell, here's the link: Instrument Cluster Circuit Board with Built in Limiter 1972 - 1976 Duster Valiant Dart A-Body (not sponsored).
Here are two videos where I found out how to ground and test the gauges -----
