Challenger rallye gauges don`t function???

!973 Challenger. Rallye gauges. I used two D batteries and alligator clips to test all the individual gauges. All gauges moved to the center. I believe all the gauges to be good. The voltage regulator is new. Just recently i found the 3 way wire that jumps to the other gauges. ( the wire that daisy chains them together). With everything plugged in i still have no gauges. What am i missing here ? Thank you for the help !

My 73 had ground issues. I had to add a jumper to get a better ground.

Check your voltage at the limiter even if it's new it could be bad.

Make sure it’s screwed to the dash frame. That is how it’s grounded.

Is the ground reinforcement wire in tact?

I don’t recall a ground strap or wire . ? Could you explain where the ground goes to and from ? What should be hot on the voltage reg ? Thanks .

Like he said, the dash frame is supposed to be the ground. In my case I couldn't get a good ground no matter how much I cleaned and tightened it so I added a wire from the metal gauge cluster to the ground wire under the steering column. that grounds the dash to the column.

If the E body is like the 71 B body, the gauge mounting is kind of hap hazard, so the factory added a ground strap from the panel to the left metal frame work of the body. It shows it in the service manual.

Strap? Is a regular wire the harness got to attach to a J nut with a screw to dashframe. The other end of the wire plugs straight to a VL bracket provision on rallye cluster and is on the multipin conector on standard clusters. On B bodies at least.

BE CAREFULL... if the VL is NOT grounded you can BURN the gauges. The VL requires - and + to work. If - is missed the points inside will keep closed allowing 12 volts to the gauges. The ground wire must be in place. The chassis ground to cluster is also good to be there and nice..

on pic the VL with the bracket provision for the ground plug. The wire gets a wider terminal ( prong is also wider ) to save from connect a diff wire there which is not the propper ground wire

Thanks for the replies. I am about to go to the garage and dig into it. I will report back .

I removed the wires to see the VL. The light blue wire coming from the VL makes a connection to two gauges . Do I have to add a jumper wire to have all three connected ? Thanks

Edit . A connection between the light blue /gray on the oil gauge and the empty dark blue/ post . On the gas gauge .

Like this ?

Yes. Normally the wire feeding between gauges and VL is black. Dunno wher it comes that one.

FYI

New VL harness

.....

Thanks for the help ! I`m gonna order the new harness and I will report back . One other thing. Using a test light on the gauges the light pulses like a turn signal. Does that show the VL is working? Thanks again !

Yes that's the way it limits the voltage.

The problem is the jumper should have 4 connections on it not 3. You can see it in the picture on ebay link of back of gauge and on the wire diagram. The 1 you have might be from a standard dash.

UPDATE: Installed new VL harness to oil gas and temp. Went to hook up ammeter. Red connected . As soon as I touched black it turned red hot in my fingers . No damage anywhere but woah. So I reconnected the leads for the ammeter back together . This is how it has been wired for last 20 years. Besides the ammeter leads being connected everything is wired as it should . Starting with oil gauge . Using a test light both posts will pulse like a turn signal.The wire on the oil pressure sensor is also pulsing. Prior to the new harness oil wire was dead. So i thought i had a good gauge , its wired correctly. I have hot at the oil sensor . Why no gauge ? Bad sensor? P.S I`m just highlighting oil gauge because i feel easiest to get working . Thanks for all the help . If you have advice please explain it to me in the simplest terms. Like i`m 5 . 😂

Is being a bit hard to read you.

yes you can get sender damaged... or gray wire.

about ammeter. after 50 years of use and abuse there is a chance the ammeter isolators are gone now... they could be already cracked quite ago but with the movement it could miss a piece and is being grounded. Time to remove the assembly and replace the isolators. It would be even better reinforce the ammeter studs to the shunt inside

https://premiumdashdecals.com/shop/dodge/dart/dart-demon/all-car-lines-ammeter-insulator/

some reading about how an ammeter is inside here:

https://www.forbbodiesonly.com/moparforum/threads/dissection-and-study-of-a-mopar-ammeter.199179/

Yes the rectangle isolator piece is missing . What material could I use in its place ? What size nuts / thread go on the ammeter post ? I’m gonna retest the gauges and make sure they are good. Would the red wire touching the back of gauge cluster without the isolator cause a short or potential melt down ? Thanks .

Yes you need to isolate the studs on the ammeter, otherwise it's meltdown/fire time, you could use some electrical insulated fiber washers, they need to be under the nuts that will tighten the ammeter studs to the housing, I'd recommend you buy/purchase a test meter, not a test light, to check for continuity/ground after you install the insulated washers under the ammeter retaining nuts, then ground one lead of the test meter to the cluster main housing and test each of the ammeter studs with the other lead while maintaining ground with the first/black lead of the meter, make sure the meter is on continuity/Omega, depending on the type of meter you have: digital or analog, it may also have an audible sound/buzz for ground/continuity, needle movement or digital display? whatever it is, you DON'T want any ground or continuity when probing the ammeter studs individually while maintaining ground with the black lead on the main cluster, if you have ground/continuity then either you didn't properly isolate the studs, the gauge may be defective, or a host of other maladies we can guess at all day, you really need a good meter to help you find/solve issues.... FYI: depending on your meter the only continuity you want to see on the ammeter studs is when you apply both test probes to each stud at the same time....AFTER you've confirmed each stud is isolated from the cluster housing/chassis ground

As far as the oil gauge function, make sure you have the correct sending unit it should look like this....



Mike

Thank you . First I’m gonna test all four gauges. Next install the insulator on the ammeter. Then I will test as per dayclona . I will report back .

Why worry about the insulator material? Just get them already made from that seller. It uses two of them! One inside and another one outside, not just the one visible outside.

And sure any contact of any of the ammeter studs or shunt inside or outside with the cluster housing with make a HUGE fail. ALL THE POWER to the car runs throught that wires and gauge, except the starter motor.

Do it yourself a favor and check that ammeter inside and outside, not just because the insulators but also for tight or loosen studs inside the ammeter. That a very missunderstood and hated gauge because just afew guys really understands its function and how it works. Is a hard to beat gauge but really abused along the years, however very usefull if you understand its readings.

And get a nice powerfull alt and couple of parallel wire paths out of the bulkhead will help on get the charging system propperly balanced and protect all the charging system. Later will post a few threads about that.

UPDATE / what happened report. I now understand what happened. I installed the new/correct harness from the voltage limiter to the oil,gas and temp gauges. While i was connecting everything the insulator on the back of the amp gauge fell off. I connected the red . When i went to connect the black ..... hot hot hot. I disconnected everything . I found the damaged insulator on the floor mat. I am now a member of now you know club. After a break i went back and tested the gauges. Gas and temp dead . Oil and alt still work. The posts on the alt gauge were very loose and one broke off on the inside during removal. So all my wiring is fine. Voltage limiter is grounded and working. With 3 dead gauges i feel my best move is to order all 4 new . I will get new oil pressure sensor. Getting the gas gauge to work gonna be another task. Thank you so much for all the help.

😡😡

thanks for posting the update as it may help someone down the road
As far as the broken insulator

Be careful with grounding also. After my full resto (that I did) my electronics were wacky too. Discovered I had a bad ground to the dash frame that I repainted before reinstallation. Scraped some paint off, reattached the ground, no more problems.

I think Ammeter could be fixed using a screw and nut ( not a thick one ) to replace the stud at the shunt. The ammeter will "pop out" the nuts thickness but I think the cluster bezel still have room for that, and maybe the shunt stud provision can be bent/shaped a bit to save that. Some indexing of the nut could be required for a correct fit into the housing provision for the amm, then some lead added for better conductivity between screw and shunt and also locking the nut. Shure the isolation gets the hole made for the squared shape of the stud on the base to keep in place the assembly but can be made to work centering the screws when reasembling. As far I recall the repro piece you probably buy will get bolt and nut anyway, not any more a pressed in stud like originals. That's at least what I recall have seen around on the web about the new repro ammeters thought

I'm wondering how the gas and tem gauges could get damaged if they were in working order.

Note: they could be also fixed if the wire inside got burnt at an accesible area to twist them and get them joint again.

another thanks for the update !
two ways these kind of replies help. one, so guys that haven't yet had to deal with "xxxx" problem get a heads up on what to expect, and two, so guys like me that "forget" are reminded about what we did in the same situation.