70 rallye cluster gauges not working

[Wcotner96]

The oil gauge, temp and fuel gauge all do not work on my 70 RR, the cluster is definitely not in perfect condition. I’ve had it out before and all connections are solid from the harness. I’m not sure if there’s a ground wire for the cluster as there wasn’t a specific one unless it’s within a harness connection. The weird thing is when I key on the oil pressure gauge goes to like 70-80 then goes back to zero when I turn car on. Temp and fuel never move. Could the voltage limiter be the culprit? I got a new harness for the tic tock tach but neither the tach or clock work(assume it needs rebuilt) any ideas where to start would be greatly appreciated

 

[BeepBeepRR]

Check the Voltage limiter. Its the small box on the back.

 

[Wcotner96]

Check the Voltage limiter. Its the small box on the back.

Thank you. I’m gonna take a look tomorrow at it.

 

[Nacho-RT74]

Voltage limiter is just for temp, oil and gas gauges.

Ammeter, clock, tach are independent.

Speedo is not an electric gauge.

Cluster gets ground (wired and chassis) but oil, temp and gas don’t need it. Senders send variable ground for them. Voltage limiter does need ground thought. A missed ground at voltage limiter can burn gauges thought, allowing a full 12 volts path to them where they just handle 5 volts.

You can test gauges individually thought, feeding studs with any dc voltage source less than 5 volts.

 

[69_A12_6BBL]

The oil gauge, temp and fuel gauge all do not work on my 70 RR, the cluster is definitely not in perfect condition. I’ve had it out before and all connections are solid from the harness. I’m not sure if there’s a ground wire for the cluster as there wasn’t a specific one unless it’s within a harness connection. The weird thing is when I key on the oil pressure gauge goes to like 70-80 then goes back to zero when I turn car on. Temp and fuel never move. Could the voltage limiter be the culprit? I got a new harness for the tic tock tach but neither the tach or clock work(assume it needs rebuilt) any ideas where to start would be greatly appreciated

You have the Rallye (round gauges) or long Speedometer type? Sometimes it’s the pigtail connector to cluster itself, or can be 1 burned thru circuit board “Lead”, the 2 different cluster types usually lean toward one or the other prob.
(Sweep Style Burned/Circuit board photo) <— THIS is common with both. You’re probably gonna need to replace that circuit board, might as well now since we know where to get a GOOD one! You can also see in top photo, how one “Pid’ or pin has bent or at an angle, causing loss of voltage to all 3 other guages, (Fuel gauge probs can be a different issue)