the fuel and temp guages do not work on my 70duster rally dash. I know nothing about electrical problems except for changing a fuse or bulbs.I put on a new sending unit for the temp. and have power to the unit but absolutely no reading on the guage.The voltage limiter is not on the back of the cluster and was wondering if that could be the problem. I also couldn't get a test light to light up on the wire going to the gas tank at the tank.Has anyone had any luck using a sunpro or any aftermarket under the dash fuel gauge? and should I go in that direction?

Without the voltage limiter the gauges won't work. Install one before you go trying to redo everything.

Thanks Stumpy, can they be found locally like in a Radio Shack? I saw one on ebay or somewhere for 9.95

Parts store or Ebay. Radio shack doesn't handle them.

The limiter is in your fuel gauge on that dash.

I thought all the rally dashes had them?

they do but it's in your fuel gauge its self.

You can test it in the car without taking the
dash out.

how do you know they are getting voltage?

I'm not sure they are getting voltage,the wire that attaches to the temp. sending unit lights up (with a test light)when I turn the key on

Here's a like to a site that explains how your
voltage regulator work inside the fuel gauge on
a rallye dash. I will try to copy a few pages from
my service manual for you that describe how to test
the gauges and limiter.

http://www.demonivr.com/Chrysler%20Rallye%20Gauges.html

OOPS!! I missed the Rally dash part.

I know you knew that Stumpy, he's going to wish
it were a non rallye when he is working on it

Mine never worked right until I swapped out the
fuel for an IVR gauge. They work pretty well.

should I say the heck with it and buy one of the under dash guages? From alot of what I hearing most of these mopar guages in 40 year old cars seem to have alot of problems not working

I'm almost positive that you should NOT have a constant test light illumination when you probe the sending unit connectors.....there should be "Pulsating" power...i.e...the test light should flash every 2 seconds.
That is the way the limiter works...."limited" voltage....otherwise the guages would pin high.

When my limiter-gas gauge quit, I had oil pres showing incorrect also. All 3 gauges seamed to read half of what they should. I'm the stinker that got the last gauge in the dealer parts system, and that was in about 1996.

you are so right about the flashing light. I just went out to the garage and checked it. It continues to flash. I took the under dash trio of oil,temp,and amps off the car sometime ago and bought new sending units for oil and temp.The oil guage works but seems to read high on the guage about three fourths the way upand when I had a brand new duster back in 1970 I don't remeber it ever being any higher than halfway. When the under dash unit was on it usually red around 40-50 lbs pressure.

I thought the external voltage limiter was only for the fuel and temp guage to break down the voltage to 5 volts to keep the guage from burning up?

I remember watching the 3 gauge readings fall while stopped at a red light. The ammeter being an independent gauge isolated from the rest, worked as it should.

Pull the wires off your oil and temp senders and
ground them. See if the gauges start moving. This
should help narrow it down as to what the issue is.
If the needles move the gauges are at least moving.

The gas guage has a set of contact's in it that pulsate in order to provide 5 volts out.

If the dash is out you can test each guage with some batteries hooked together (3 volts will move each guage a little more than 1/2.

You also have to be certain all the curcuit board connection's (including the crimped pins for the harness plug are clean and tight).

I have converted working dashes over to the "Ehrenburg" solid state regulators and am ready to do another with RT Engineerings new regulator.

I highly recommend it even if the original is working!

The RT engineering one is more money BUT mimics the factory performance AND won't fry your working guages should a ground loss occur.

Also , checking everything with a multimeter is better than the factory procedure which uses a test light.

It will show the exact voltage to each guage, when your only using 5 volts, 1 volt either way is significant.