gauges gone wonky

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jhdeval

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So I changed my ignition switch and now my gauges fuel and temp have gone wonky. Fuel does not read and temp which was fine before goes up and down. Is it possible my electronic regulator bit the big one? Any ideas they were fine before the change.
 
It's not likely that the voltage regulator for the charging system is causing this but the voltage limiter for the gauges is a likely suspect. I can't remember your year and model but some of the early fuel gauges have the limiter built into it. The later ones used a separate limiter. There are solid state ones available for both systems.
 
What cuda said. On these old cars, once you disturb one thing, all the other old parts want in on it. It's old tired iron; it was going to go out on the next pothole, anyhow.

For example, did the mad ammeter bypass, good . 50 miles, speedometer goes out, new one, 20 miles, then need a re-pop cluster board, (this is getting old, and we are getting too fast in dropping the column, etc.) Now the gas gauge, with new sender, is empty at 1/4. BWHAAAAAAA lol
 
Did you pull the whole cluster to change the switch. I believe the four mounting screws ground the metal cluster to the dash frame when tightened. Make sure your cluster screws are tight. I believe I was working on one of my gages one time with the cluster hanging out and had to ground the metal cluster to get the gages to work. Jayson
 
I just pulled the ignition switch below the dash. I did not touch the mounting screws. I have upgraded to a demonivr voltage limiter a while back.

green1 I feel you on the gauges weird readings. My speedo is off about 8 mph after 60 but fine before that. The fuel gauge reads WAY low like more then a quarter tank off. The temp gauge seems to be about right and the ammeter seems ok. I am seriously thinking about just changing ALL the gauges. But I don't want to cut up the wiring.
 
The fuel gauge reads WAY low like more then a quarter tank off.
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 Probably a bad ground, check the metal strap bridging sending unit over rubber fuel line to steel fuel line making sure its contact points are clean, then check for voltage drop between sending unit & neg battery terminal. Or, problem could be a mal adjusted aftermarket sending unit.

My speedo is off about 8 mph after 60 but fine
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 Spedo can be sent out to be rebuilt to new & recalibrated, or just find a good used one.
Hacking up dash for after market gages is a lot of work, and expensive.
 
Was everything working correctly before you changed the ignition switch ?
If there is/was a problem in either gauge the internal protection in the IVR will cause it to go on and off. That could explain the needle going up and down in cycles.
 
If this happened immediately after changing the switch, I'd suggest it is probably something loose in the wiring, bad connection, etc.

But I'm not familiar with the wiring in those early cars.

Check the IGN feed out of the switch, should be one wire break off to feed the cluster. IF it's "y'd" off right at the switch, it might be a poor connection there

You might have bumped it loose at the cluster. Do those use a connector on the PC board? Typical failure, as you might have pulled on the harness enough to disturb it.

It MIGHT JUST be time to pull the cluster and "go through" it

In my case, there were several problems which I had to fix

Several of the PC board connections were broken, and there were ground issues. I ended up eliminating the original connectors, and went to Radio Shack and bought some "Molex" style connectors

The nuts on the gauges may not be making connection, due to corrosion, even though they seem tight
 
RedFish the gauges worked before the ignition switch change. I do have the DemonIVR but the temp gauge goes up and down the gas gauge does not work at all anymore.

67Dart273 It did happen directly after changing the switch. I guess your right I am going to have to look again for any broken pieces. I don't want to replace the cluster but I am so tired of the constant problems coming from the cluster.
 
You can use jumpers to bypass broken pins, and delaminated conductor path on board.
 
Okay so it appears my gas gauge just has a faulty ground. I am going to need to look at that but the temp gauge is still surging. Could it be the thermostat? How does it work and how do I know? I don't think it is the sensor as I have replaced that less then a year ago.
 
If it's surging, the most likely suspect is the voltage limiter
 
Kelly Pate said:
:eek:ops::violent1:


I HAVE PULLED THE INSTRUMENT PANEL OUT,,, I CAN'T FIND A "VOLTAGE LIMITER ANYWHERE ? ? HELP ! !
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I may have led you astray, on your car it's I think inside the fuel gauge. See if the fuel gauge has three terminals. One is ignition input, one is the fuel gauge sender, and one is the output of the limiter, which jumpers over to the other gauge(s), temp, and oil, if you have an oil ga.

If you search around, or Redfish may chime in here, there are ways to bypass the original fuel gauge one and incorporate an external "add on" electronic one.

Don't ask why Ma did that--pretty silly if ya as' me
 
jhdeval said:
Okay so it appears my gas gauge just has a faulty ground. I am going to need to look at that but the temp gauge is still surging. Could it be the thermostat? How does it work and how do I know? I don't think it is the sensor as I have replaced that less then a year ago.
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I dont know how your fuel gauge could have had a faulty ground It gets 5 volts input on one post and a signal from the sender on the other post. The gauge itself isn't chassis gounded.
Those gauges having 3 posts do have the limiter housed inside and that gauge is chassis grounded by the manner in which it is mounted in the housing to providea ground path for the limiter.
Even in thiese gaugss the 5 volt circuit is not and should not be chassis grounded.

In the case of the original thread starter, email me. I can talk you through a few tests and find then fix the fault.
As for others posting their issues here, that will only cause confusion for everyone because they aren't all the same.
Better o start your own thread or just contact me diredtly.
 
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