Instrument voltage regulator on the fritz?

[Wollfen]

I have been watching my gauges on the Plymouth GT while driving it and can see that the temp gauge reads almost on full hot and the car is not boiling. Also the gas gauge reads less than a quarter with half a tank of gas, so I'm thinking its the regulator that screws to the back of the instrument cluster, anybody concur? Also where do I get one of those?

 

[commando1]

The 5V regulator is available on eBay. I got mine from AutoZone.
There's a guy who makes a solid state regulator but I burned out two of those. There's DIY instructions on the net for the solid state but they are no better.
OEM

Radio Shack DIY

 

[Wollfen]

If it is definitely 5V output then I can grab one off ebay for sure.

 

[commando1]

If it is definitely 5V output then I can grab one off ebay for sure.

Absolutely positively 99.9% sure...

 

[Wollfen]

Absolutely positively 99.9% sure...

Lol, I'm that sure too.

 

[66/440]

The 5V regulator is available on eBay. I got mine from AutoZone.
There's a guy who makes a solid state regulator but I burned out two of those. There's DIY instructions on the net for the solid state but they are no better.
OEM

Radio Shack DIY

Stan, who's solid state product were you using that burned out? I have one installed from DEMONIVR that is working well but I want to make sure that I don't have any issues to look forward to.

 

[66/440]

I have been watching my gauges on the Plymouth GT while driving it and can see that the temp gauge reads almost on full hot and the car is not boiling. Also the gas gauge reads less than a quarter with half a tank of gas, so I'm thinking its the regulator that screws to the back of the instrument cluster, anybody concur? Also where do I get one of those?

Correct me if I am wrong but isn't gauge calibration done in each gauge? The IVR only serves to regulate from 12v to 5v for water temp, oil pressure and fuel gauges. On some mid late 60's models if the IVR is faulty or missing your car will not start. Not sure this applies to your '71. Could it be a poor ground?

 

[Big_John]

I have been watching my gauges on the Plymouth GT while driving it and can see that the temp gauge reads almost on full hot and the car is not boiling. Also the gas gauge reads less than a quarter with half a tank of gas, so I'm thinking its the regulator that screws to the back of the instrument cluster, anybody concur? Also where do I get one of those?

I think the regulator could do this, but it's also possibly two different issues.

Did the temp gauge come up to hot immediately or did it come up slowly? I would also look at the wire from the temp sender to be sure it's not shorted to ground somewhere. The gas gauge could be the sender or a bad ground to the sender.

Either way, the regulator is cheap enough to change.

 

[commando1]

The VR just takes a few seconds to test if you put it on the table.
It doesnt put out a constant 5V.
It puts out 12v off and on in equal time increments for an average of ~5-6V.

 

[Gerald Morris]

Rock Auto vends a decent one from Standard here: More Information for STANDARD MOTOR PRODUCTS VRC601

Here's a cheaper No-Name on eBay: VRC601 Instrument Cluster Voltage Regulator FITS Dodge, Chrysler, Plymouth vehic

I use USB heavily at times also, so will likely soon supplement the instrument cluster 6V supply w a decent 10A 5V digital grade supply. here's a cool lookin rig, purports to give 12A w surge protection: Multi 10 Port Fast USB Charging Station 12A Power Adapter with Surge Protection

I wouldn't advise mixing the instrument cluster power bus with anything digital. Let the VRC-601 do its thing there. IFF you find an NOS instrument cluster supply, which does a crude electro-mechanical dance which Stan already described, you could flatten the power down a bit with a big capacitor, if you see a need for that. I would, as even genuine NOS gauges, lights and such will last longer if the voltage isn't spiking and dipping on them all the time. U can probably get a big power cap such as the filter caps the sound-freaks dig, and then if you're a REAL power purist, get a power resistor, say 10K, 10W and do a crude filter with a decent RC constant. You may want to put the old skool instrument cluster regulatoron an O-scope and then run your motor up and down through your normal range of RPMs to see what the period of your supplyis going to be, min and max. Then you caqn make a judgement call, say, around 2k to 3k rpm, calculate your tau, parallel the R and C to ground from your cluster power bus, and see how flat you get it on the scope.

This IS my idea of a joke, but one which will work.

 

[Wollfen]

The gauges come up real slow , so I know there isn't a short somewhere. Also the sender and ground are brand new and fitted properly, I made doubly sure of that because i am tied of getting under the car. I think I'm losing patience in my old age I have been thinking about the ground issue in regards to the cluster since I am getting too high a read on the temp gauge and not high enough on the fuel gauge. Now that I have been thinking about it, if the regulator was faulty then all the gauges would do the same thing. So now I'm thinking I have to check for a loose,corroded or faulty connection.

 

[Turboomni]

What all does this regulator supply power to? Reason I ask is my fuel gauge and temp gauge don't work.

 

[Wollfen]

What all does this regulator supply power to? Reason I ask is my fuel gauge and temp gauge don't work.

It brings the voltage down from 12V to 5V for the gauges, if it dies altogether your gauges dont work at all.

 

[Wollfen]

For my car I will be checking the ground at the Instrument cluster first. That can bring about issues too. Usually gauges are very reliable and it is the sender units, or corroded wires etc that causes the problems. Start simple then work your way up. Me, I am taking a break, hence no news.

 

[Turboomni]

So temp and fuel gauges and tach if so equipped ,,anything else?

 

[Mr C]

I had this happen and I found that when the regulator sticks, all of the gauges rise and peg out together at the same time (because they are all getting too much juice). If it's not doing that, you likely have other, independent issues (hole in float leading to partially sunk float and erroneous reading, poor ground, etc).

 

[Turboomni]

I had this happen and I found that when the regulator sticks, all of the gauges rise and peg out together at the same time (because they are all getting too much juice). If it's not doing that, you likely have other, independent issues (hole in float leading to partially sunk float and erroneous reading, poor ground, etc).

So if it fails completely no gauges will work at all or show no reading I would guess.
Do the regulators tend to stick usually or can they fail completely too? Reason I ask is both the fuel level and temp are not operative in my Fury.

 

[Wollfen]

I am pretty sure that only the fuel and temp gauges are controlled by that regulator, since the amp gauge is the only other one that has a needle, it has direct power from the battery. It can be the voltage regulator or as I have mentioned, may be a bad earth or even something simpler like a loose wire or something.

 

[Mr C]

So if it fails completely no gauges will work at all or show no reading I would guess.
Do the regulators tend to stick usually or can they fail completely too? Reason I ask is both the fuel level and temp are not operative in my Fury.

The instrument voltage regulator (IVR) is like a set of points, so it can fail in either open or closed positions. Here's a excerpt from article at link:

The IVR has a heated bi-metal bar similar to those found in the gauges. As the bar moves, it forces a set of points open and closed to provide a steady flow of electricity to the gauge. The instruments see it as an average of five volts, what they were designed for. If the contact points stay open too long, you'll see simultaneous low readings, and if they stay closed too long, you'll see simultaneous high readings.

Instrument Gauge Repair - Tech Articles - Mopar Muscle Magazine

 

[Turboomni]

Thanks for posting that Mr C