Vintage Mustang Forums banner
  • Hey everyone! Enter your ride HERE to be a part JUNE's Ride of the Month Challenge!
  • May's Ride of the Month contest ended with a tie! Go to this thread to vote on the winner! VOTE HERE
1 - 10 of 10 Posts

·
Registered
Joined
·
276 Posts
Discussion Starter · #1 ·
I have seen several of these gauges with warped plastic faces. I assume that means the gauge itself is toast?

 

·
Registered
Joined
·
276 Posts
Discussion Starter · #3 ·
Thank you. I will have to try that. That gauge came from a cluster I bought recently. I just had someone try to sell me another one of these with a warped face for $170...yikes!
 

·
Registered
Joined
·
276 Posts
Discussion Starter · #4 ·
OK, the needle moved when I tried the battery trick. I also tried it on another gauge from a non-tach cluster that was not warped and they both reacted the same. But that doesn't explain why one of these would get hot enough to warp a hard plastic face that is about 1/16" thick. Any thoughts?
I have seen three with the same issue in my searches.
 

·
Premium Member
Joined
·
833 Posts
I have a tach dash in my car with the same issue. I was told it was a bad voltage regulator on the back of the cluster or possibly a tach cluster that was plugged into a car with non-tach wiring.
Again, I'm not 100% but that is what I have been told.
John
 

·
Registered
Joined
·
8,677 Posts
AFAIK, the reason you see that guage melted is due to someone putting a tachometer cluster in a non-tachometer car. The wiring is different between the two cars and it isn't a simple swap. The wiring connector pin that did go to the ammmeter gauge now goes to the temperature gauge. The ammmeter is not regulated voltage, thus the overheating. If that temp guage actually works then I am amazed!
 

·
Registered
Joined
·
276 Posts
Discussion Starter · #8 ·
That probably makes some sense except for the fact that the printed circuit boards do not interchange between the two instrument clusters. That means the circuit feeding the temp gauge is still regulated on one side, same as if it had the correct harness. But you can still plug the harness for a non-tach dash into the circuit board for a tach dash. The difference is that the pin which feeds one of the back lights on the non-tach dash is now feeding the voltage regulator and the non-regulated side of the temp gauge is being fed by a pin that would have fed one side of the alt (amp) gauge on the non-tach dash. I assume that last part is what causes the overheating, not the fact that it is unregulated.
 

·
Registered
Joined
·
1,356 Posts
This results from plugging a tach dash to a non-tach harness.
There is an actual heating coil inside the gauge that normally operates regulated to less than 12 volts.
The outside gauges are actually identical except for faces, housings and minor calbration.
Well, the Alt gauge is different but the Fuel and Temp from a tach dash and the Oil gauge from a non-tach are mechanically the same.

The function of the gauge is usually still there...it is now just ugly!

Bruce
 

·
Registered
Joined
·
8,677 Posts
blksn8k said:
The difference is that the pin which feeds one of the back lights on the non-tach dash is now feeding the voltage regulator and the non-regulated side of the temp gauge is being fed by a pin that would have fed one side of the alt (amp) gauge on the non-tach dash. I assume that last part is what causes the overheating, not the fact that it is unregulated.
Precisely!
 
1 - 10 of 10 Posts
Top