Gauges Fogging up:

[Captain D]

Hi all,

Does anyone happen to know why some of the gauges in the dash fog up by chance? The other day, we had the 69' Charger out for a 15 minute drive and the fuel and alternator gauges began to fog up  .

Any info would be appreciated and interesting to learn,
All the best,
Aaron

[440]

 I would check alternate output voltage and cluster regulator output. Mine started forging up due to a bad voltage regulator.

[Captain D]

Thank you 440 for the reply,

Couple more questions here please:

1.) Where is the 'cluster regulator output' located at exactly (I'm kind of surprised that it may be the voltage regulator since it was replaced not too long ago)?
2.) And, is this something that may need replaced ASAP in order to prevent damage to something other in the car, in general?

Thanks again,
Aaron

[Dino]

Thank you 440 for the reply,

Couple more questions here please:

1.) Where is the 'cluster regulator output' located at exactly (I'm kind of surprised that it may be the voltage regulator since it was replaced not too long ago)?
2.) And, is this something that may need replaced ASAP in order to prevent damage to something other in the car, in general?

Thanks again,
Aaron

1)Plugged into the back of the cluster, right into the circuit board.  Mine died and killed one of my gauges. 

2)It can't hurt anything else in the car but it can fry fuel, oil and temp gauges before you can say Supercalifragilisticexpialidocious!

Unless you have a concours resto car and want to keep it that way, replace it with a solid state limiter asap.  I just bought the IVR4 from RTE Specialties.  Your gauges will act as they should without the risk of them being crispy fried.

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

[billschroeder5842]

I put a solid state limiter in mine a couple of weeks ago for the peace of mmind. Well worth it.

[440]

There are two Voltage Regulators, one on the firewall for the charging system, and one on the back side of the cluster for the gauges. I agree solid state is the way to go although not cheap compared to the points style regulator, but then again it's cheap insurance to protect the gauges. If things go wrong it just shuts down. Alternator voltage should be around 14v and the cluster regulator should be 5v I believe. My points style regulator failed and wiped out the cluster regulator, which in turn wiped out the gauges    It can all go pear shaped rather quickly in a matter of minutes. A faulty Voltage regulator could wipe out a new cluster regulator.

As stated the cluster regulator is mounted on the back of the gauge cluster and is quite tricky to get at while installed in the car. I suggest pulling the cluster to test it (this also involves dropping the column slightly), just make sure your ground the cluster to the dash frame with a wire.

Another sign of a stuck or shorted cluster regulator is the gauges will peg. You didn't specify if they did or not.

[Captain D]

Thank you gents for the replies,

I apologize in the delayed response back - I've been putting in a lot of overtime @ work last week. As for the cluster itself as discussed here, I was surprised that it could possibly be the cluster regulator/voltage limiter for everything on this cluster has been restored and replaced altogether a few months ago. However, I realize that even replaced and new items do not guarantee that it'll last any lengthy amount of time  . As you previously stated, "A faulty Voltage regulator could wipe out a new cluster regulator."

I actually took the car out again 2-3 more times for at least 15 minute drives each time and kept my eye on the gauges. Since I'm a newbie, I'm unsure what you mean by the gauges "pegging," but during those 15-20 minute trips the gauges worked perfectly fine and now no indication of the fogging problem at all. A friend of mine suggested that perhaps that there simply was some moisture or dampness that may have possibly been the issue. Just out of curiosity - if the problem is, in fact, the voltage regulator would that be something that would make the gauges fog up constantly or only hit and miss as I've noticed here? In other words, to help narrow down the problem, would a faulty regulator cause the gauges to fog up constantly? If that's the case, since mine happened only once could that possibly rule out the regulator?

Thanks again,
Aaron