Trooperthorn

I had to replace one on my crew years ago, but I can't remember if it was for the fuel gauge or oil or what.

Moparmax

Dash - Gauge Volt Limiter - NOS # 3592899

Jim Lane

It is a voltage regulator, all of the old cars and trucks had them, but not as much any more.

Dieselbuilder

thats a thingahbot that fits on the watyoumacallet

Thunderhog

Like was said before, it's a voltage regulator. the gauges use 5 volts, and since voltage fluctuates on our 12 volt systems, it keeps voltage a nice even 5 volts... in theroy!

Thiss

Could that thing a ma bob cause my voltage Gage to dance?

Crossy's son

never seen one of them on any of the 90-93 clusters i've had apart

Jim Lane

The 90-93 should all VDO instrumentation (electronic speedometer) and the circuitry is built in. 60's, 70's and 80's should all have them.
Some snapped in with a snap like terminal while the others had blade terminals.

Most of the old regulators were a thermal type where a bimetallic strip was wrapped with nichrome wire as the current through the wire heated the bimetallic strip it would bend and open the contacts, as the circuit was open it would cool off again closing the contacts and the cycle starts over. This crude pulse was then smoothed over using a capacitor to give usually the fuel, temp and oil gauge a regulated 5 volts.

Now you can easily build one using an LM-7805 regulator or an LM-317 adjustable regulator and a few support components.

Jim

Trooperthorn

Thanks folks. I got this thinkin' goin' on in my head about blending my first gen ctd with my old instruments in my 77 crew. I am no electronics expert, but I am trying to understand these things.

Thunderhog

[Most of the old regulators were a thermal type where a bimetallic strip was wrapped with nichrome wire as the current through the wire heated the bimetallic strip it would bend and open the contacts, as the circuit was open it would cool off again closing the contacts and the cycle starts over. This crude pulse was then smoothed over using a capacitor to give usually the fuel, temp and oil gauge a regulated 5 volts.)
JIM LANE QUOTE

And they often "stick" which causes your gauges to swing to the high side side for a moment, then return to normal.
This is a common problem for all old Mopars.
This is EXACTLY why I changed my 1985 truck over to a 1993 cluster.
Now i have an accurate electronic speedometer, a voltage guage (instead of a stupid AMP guage) and VDO stepper motor guages.
It was really pretty easy.
WIN, WIN,WIN!

griffination

Gotta say if you plan on keeping the old cluster then converting the regulator to electronic as mentioned above makes things much better. I did this to my old 78' Ferd and the gauges were notably more stable and accurate, best of all the parts all fit neatly into the original regulator box so it appears stock.