Instrument panel dead - Rally Dash

[CudaJon]

Today I was driving minding my own business in my 73 Cuda with the rally dash and notice my oil pressure was below low and my heart skipped a beat. But then noticed all other instrumentation - Gas and Temp dead with my alternator needle looking also funny, in the middle with the car running but with the car off, it went all the way to C.  BTW, everything else seems to work, clock (which keeps excellent time)  radio, blinkers, horn. I did have to stop and pick up my son from work and the car did turn over with no hesitation.  I didn't notice any smoke nor smell. Can the group give me some advice as to where to start looking.     Thank you very much in advance!!

[dodj]

Dash voltage regulator.

[CudaJon]

Dash voltage regulator! Really are you sure - where is this guy located?

[mjb765]

It's a little silver box mounted to the back of the instrument cluster

[CudaJon]

Is it also called a voltage limiter??

[Lbs]

Yes, limits voltage to about 5 volts...........or in your case 0 volts.  :useless


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[CudaJon]

OK got it - now the big question, actually two.  First I'm going to a car show this Sunday, I'm thinking this is ok to drive?? Second question and I'm afraid to ask but do I need to remove the cluster or can I reach back there to unplug and replug in a new regulator? Thanks!!!

[lulurocks]

Did you check the fuse that feeds power to the limiter and gauges ,  I think it's fuse #6 20 amp  make sure the fuse holder clips or fuse is not corroded  or blown 

[Racer57]

Its safe to drive. Removing and installing the limiter without removing the dash can be pretty hard to do depending how well you can twist and turn.
But, a couple years ago when I was in the same situation as you, I removed the wires from the limiter and fastened them on a new limiter. The new one does not have to be mounted to the cluster, but it does need to be grounded. I fastened a wire to the MOUNTING TAB of the new limiter and fastened the other end to a ground.  This pic shows the limiter with a red arrow pointing to the power lead.

[CudaJon]

Thank you all for the replies, Nice picture too!  I'm most likely going to remove the panel during the winter break to replace the limiter and get familiar with the wiring. My Tach doesn't work and the gas gauge when working is wrong so I got things to do. My thinking is to follow the service manual on removing the cluster panel but will also research the threads here to make sure I'm not going to make any mistakes. Right now I'm just going to enjoy the car for a couple more months! Thanks again all

[73440]

http://www.rt-eng.com/rte/index.php/RTE_limiter

 I have seen this describe have not used but you might want to look into this

[CudaJon]

Looked at it, little steep in price considering that I assuming the OEM limiter has lasted over 40 years. I do more research when the time comes and report back. Thanks for the tip!

[mjb765]

Looked at it, little steep in price considering that I assuming the OEM limiter has lasted over 40 years. I do more research when the time comes and report back. Thanks for the tip!

The generic ones are still $40

[Racer57]

Thank you all for the replies, Nice picture too!  I'm most likely going to remove the panel during the winter break to replace the limiter and get familiar with the wiring. My Tach doesn't work and the gas gauge when working is wrong so I got things to do. My thinking is to follow the service manual on removing the cluster panel but will also research the threads here to make sure I'm not going to make any mistakes. Right now I'm just going to enjoy the car for a couple more months! Thanks again all

One suggestion before you start pulling things apart. Remove both seats, crawl under the dash and take LOTS of pictures behind the dash. Trust me, you will be glad you did. Manuals can tell you a lot, but 40year old wiring colors fade and "**** happens" between the time the car was new and you got it.

[Bullitt-]

your Ammeter is not in the circuit powered by the voltage limiter ...It's simply in line between the alternator & battery
 I'm perplexed as to what would cause it to go to the C side with the engine off.
Something you should be aware of anyway is the Fire Hazard the ammeter & associated wiring poses. Many simply bypass it wiring directly to the battery while others go this route http://www.madelectrical.com/electricaltech/amp-gauges.shtml