Gauges not working

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nursieee

Well-known member
Joined
Dec 8, 2019
Messages
68
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Location
Sweden
My Car
Ford Mustang Fastback Mach 1 1973
 If none of the gauges work ammeter, oil pressure, engine temp. Which is the most likley problem. Andd by the way. Radio not working except light, tach not working, fuel gauge not working, clock not working. Some of the lights in the gauges consol are working and some are not. Circuitboard is new, volt regulator is new. Tach is new from rcktman.

 
Ammeter barely moves in the best (worst?) conditions and is independent of the other gauges.  You can test the gauges by removing the sending unit line at the unit (e.g. fuel, oil pressure, water temperature) and briefly grounding the plug: the gauge should peg high.  If not, the most likely suspect is a bad constant voltage regulator on the back of the dash cluster.  This CVR DOES NOT control the ammeter or lights.  Just because it is new doesn't mean it is not suspect. 

I've found the input line into the CVR may have high resistance (more than the 9.5 ohms), but you should still see some gauge movement.  I suspect your dash cluster connector pins need cleaning (a good pencil eraser works well).  If none of this helps, it is time for a thorough investigation of wiring for more trouble-shooting. 

Your aftermarket tach needs 3 signals: ground, power, and a signal coming from the - side of the coil.  It is independent of the rest of the dash cluster.

 
Did your car come with gauges? The ammeter has nothing in common with the other 3 gauges, which are powered by the instrument voltage regulator.

The panel lights may be burned out, improperly installed, or have bad sockets.

The tachometer likely isn't connected correctly. Red wire to switched 12 volts, black wire to ground, green wire to negative pole (that connects to distributor) of coil. Make sure you are getting 12 volts to the red wire when ignition switch is on, nothing when switch is off.

 
Yes it came with gauges.

It seems there is bad contact on the lights on the pc, think its the sockets, i tried a working lamp with socket and it worked in almost every place on the PC, the pc are new.

Oilpressure gauge is working, had to have the instrument gauges with the pc connected, water temp im guessing its ok but have to have the engine runnig for a while before it moves, getting pretty gassy in the garage.

The tach i have to tune got instructions for that from rcktmn.

Thanks.

 
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I did put the cluster dash gauges back,  the break warning lamp will lit for 1 sec when i start the engine. I suppose it is suppose to be lit when the handbrake is in?

Fuel gauge dont work. The car has been in my garage about 2 years without gas in tank and not started. Can it be oxid in the sending unit or whats the most likly wrong?

Speed gaue isnt moving. I thought it was all mechanic so i might not  got it connected right but i see som wiring connected to it a bit behind the cluster dash as well, what is that for?

 
Brake warning light is independent of the hand brake and will activate only when the key is in CRANK position.

Fuel gauge: do you have fuel now in the tank?  To test, put key in ACC, remove sending unit connector and briefly ground the fuel line pin: your gauge should go to the high/peg position.  If not, you have a break in the wire or a bad CVR on the back of the dash cluster.

 
There is nothing when i ground the fuel gauge. The 2 screws that lead to the fuel gauge is loose and one of those plastic splints is broken. Also tryed to put 12 v on those 2 screws but nothing happend with the fuel gauge?

Picked the fuelgauge apart. The 2 screws that lead power to the gauge has a very thin thread glued to them and the screws is there by splints in plastic. The plastic was cracked and the screws is loose and therfor the ultrathin glued thread had loosened from there so the fuekgauge is also broke. Good, got to get a new one.

 
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The speedometer is all mechanical. Possible causes, cable housing not connected at the speedometer or transmission,  cable broken, driven gear teeth stripped in transmission.

 
Found a an old gauge panel with supposly all gauges working including tach, on ebay, so i have a new one coming from USAto Sweden. Price 500 dollars with delivery and all extra swedish fees it will be about 1000 dollars. So ill get to next topic/problem soon.

 
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