Instrument Voltage regulator or limiter

[moparphilip383]

Hello,
I am hoping to have some clarity on the voltage regulator for my 1970 road runner instrument cluster. Recently I tried changing the voltage regulator with two limiters I had in the garage. The fuel gauge read high, Then after the second limiter the fuel and oil pressure read high. Last I installed a newer limiter that I knew works and the fuel, temp, and oil all peg. The manual says there is an open ground or the limiter is bad. It also says to place a ohm meter between the temp contact and a ground and it should vary. My question is if I check for continuity with each voltage regulator or limiter the all read different. some 56 ohms, then 66 ohms and then 75 ohms. Is there a way to bench test the limiter and anyone know what they should be? Also, does this mean the gauges are now toast?

Second the manual says and I have read online that the gauges and instrument cluster grounds to the dash. Doesn't it also ground through the negative lead to the amp gauge? Is there an way to verify or test the ground of the instrument cluster or just check the screw heads with another ground?

I also see a capacitor slipped in with the ignition terminal of the limiter in the cluster. How would I know if the capacitor isn't working? Can the capacitor be frying the limiter?

I plan on picking up a new voltage limiter tomorrow and guess a capacitor.

Thanks for you help

 

[twinscrew698]

You might want to check this out on Voltage Limiters.
Hope it helps ya somewhat as i am going to put one in my 68 RR just to be safe and do not want to end up frying my gauges.
http://rt-eng.com/rte/index.php/RTE_limiter
Installation instructions and more.
http://rt-eng.com/rte/images/a/ad/LimiterManualIVR4_c.pdf

 

[moparphilip383]

Thanks Twinscrew698,

I know it has to be the limiter. I ran into these types of problems with an ECU from Autozone, O'Rielly's then Summit racing.

The RTE is actually what I am looking for.

Mopar nationals in five short days.

Thanks Again.

 

[moparphilip383]

The rt engineering works awesome

 

[kdtjb]

The black wire on the amp gauge is not a ground. It is positive. The red wire is also positive, the amp gauge reads whats passing threw it.

 

[Propwash]

The black wire on the amp gauge is not a ground. It is positive. The red wire is also positive, the amp gauge reads whats passing threw it.

Good call!! My god man, do not try to ground anything from that stud you're considering "a negative ground" on the back side of your ammeter. Like KD mentioned, they're both positive and running one of those studs to ground would be bad. Like burning wires/fire bad.

 

[moparphilip383]

Oh yes I agree, I actually checked voltage while the dash was screwed in by making a connection from the upper dash screw to the car frame. I was actually picking up 4 to 5 volts. I do see the different circuits on the back of the dash. The parking illumination comes in the 5 pin plug with gauge circuitry. When things first started acting up I would turn on my parking lamps and get at jump in the gauge. I fried the circuit board and believe it is all because of the capacitor and voltage regulator.$