Another question on Temperature and fuel gauge not working,

Local time
7:06 AM
Joined
Dec 7, 2020
Messages
9
Reaction score
2
Location
Carbondale, Pa
Hello All,
I have been reading threads about temp and fuel gauges not working. In my case, the temperature gauge stopped working first. A few weeks later the fuel gauge stopped working. I read all of the posts. Most of them were a few years old. I have the same problem and curious if there is anything "new" to try.
I have a 66 Coronet.
Temperature gauge; My Temperature gauge was working and it stopped. The gauge doesn't move unless I ground it. When grounding it, the gauge will go to HOT. I changed the temp sending unit, I followed the violet wire to the bulhead. Unplugged the bulkhead plug, wiggled wires plugged it back in. There is power there at the sending unit plug. I wiggled and unplugged the cluster on the backside of the instrument panel. There is power going to the gauge.

Fuel gauge; I replaced the fuel sending unit a few months ago, and made sure of a good ground. All was working fine and then it just stopped reading fuel level. I checked the gauge by grounding it and the gauge is working properly. There is power to the sending unit and to the gauge.

I checked fuses .... and replaced the voltage limiter with a solid state VL. Did my best at checking connections. Is there anything else I can try? Could it be possible the the new VL is bad?

Thanks in advance
 

dadsbee

FBBO Gold Member
FBBO Gold Member
Local time
7:06 AM
Joined
Jan 29, 2018
Messages
13,468
Reaction score
37,149
Location
Midland Ontario, Canada
If your gauge goes full scale when temporarily grounding the sender wire... then there is nothing wrong gauge or vr wise. It's your senders in both cases... or their lack of a ground. Too much tape on the temp sender can isolate it... or wrong ohm range. Fuel sender not getting ground to unit or float sunk.
 

Nxcoupe

FBBO Gold Member
FBBO Gold Member
Local time
7:06 AM
Joined
Jul 4, 2021
Messages
1,622
Reaction score
1,479
Location
Red Lion, OH
If the gauges go to max when grounded, the VR is working. Where did you buy the solid state VR?
To diagnose this, you need to measure the resistance that your temp sensor has to ground. It could be that the sensor doesn't have a good ground where it is screwed in at for the temp. The fuel gauge could have had the float fall off or it could be the repop sending unit failed. You have tested the power supply and circuit integrity by grounding the sensor wire and seeing the gauge respond, so that should be good. I need to do this same thing, but mine hasn't worked reliably since I bought it.
 
Local time
7:06 AM
Joined
Dec 7, 2020
Messages
9
Reaction score
2
Location
Carbondale, Pa
If your gauge goes full scale when temporarily grounding the sender wire... then there is nothing wrong gauge or vr wise. It's your senders in both cases... or their lack of a ground. Too much tape on the temp sender can isolate it... or wrong ohm range. Fuel sender not getting ground to unit or float sunk.
Thank you both for the reply. I will pull both sending units and either fix and/or replace them so I can eliminate them from the equation.
stay safe!
 
Top