Project Notes from a Rallye Dash Overhaul including Gauges, LED Lighting Upgrade, & RetroSound Stereo Installation in a '71 Duster 340 4-speed AC car

**UPDATED 7/16/24 with a link to a time-lapse video publicly posted to my YouTube channel that I made at 5 am this morning. The quick video shows a birds-eye view of most of the rallye dash bezel removal process. the rallye dash removal from a Mopar A body. Watch carefully to see the point when I realized I had forgotten to tape the top of the steering column (D'oh!). Not shown because I started videoing after are 1) dropping the steering column 2) removing the wiper switch bezel 3) unmounting the knob radio. Take your time and do it right, lol.

**UPDATED 06/05/2024** For anyone who has viewed this article previously, you may be happy (or mad, lol) to know that I have chosen to reformat it into a "real" how-to article - what it should have been in the first place. What was posted previously was at-best, information overload, and at worst, not much help to anyone but me. For context and if you are curious, the original unedited post, including a few before and after pics, appear at the very end. You might just find some useful information in the linked PDF if you don't mind wading through a ton of information you absolutely will not care about, lol.

FEEDBACK REQUESTED: As of this update, I elected not to include any of the numerous pictures I took during the project in hopes of not cluttering the tutorial unnecessarily. There are quite a few detailed pictures in the companion article linked below. If you think adding pics to this post would be helpful, please let me know. Alternatively, if you have a need for any specific pics, please message me. Thanks.

NOTES:

• Per the service manual, I was able to successfully remove the bezel/cluster assembly without dropping the steering column. With my ’67 Barracuda, dropping the column is a required step in the service manual. With hindsight from near the end of this project, I would (and ultimately did) drop the column in this car. The reason I didn’t at first was because the AC vents would need to at least be loosened and moved or possibly completely removed first. That was a lot of messing around for me with this car that likely will not be an issue in your car. If you do not drop the column, the bezel fitment for removal/reinstallation is just too tight to ensure preventing accidental damage to the bezel during the process. When I had an issue later in this project that required starting over, I dropped the column, so I have included those steps in this tutorial.
• My project also involved installing a new RetroSound factory-looking modern sound system. Rather than cluttering this tutorial with those steps, I elected to focus on the bezel/cluster only. I posted another article that documents a very similar procedure I did on my 1967 Barracuda that includes the audio system information, which can be found HERE. If you have any questions about any of this, please feel free to private message me. I am happy to answer any questions that I can.

Bezel/Cluster Removal:

1. Disconnect the negative cable from the battery.
2. Thoroughly tape the top of the steering column and the lower dash frame area below where the bottom of the bezel contacts the frame to prevent scratches.
3. Reach up under the dash from the left footwell and disconnect the speedometer cable (unscrew it if it is a ’67, unclip it if it’s a later year) and let the cable hang inside the dash frame. Often pulling the parking brake handle toward you a bit first (engaging the parking brake) will make access to the speedo cable where it meets the speedo more easily accessible.
4. Drop the steering column by…
   • Loosen well, but do not remove the two 1/2” column collar bolts at the firewall. The collar only needs to be free enough to allow some movement. The column will only ultimately drop an inch or two maximum. NOTE: Distinguish these two bolts from the three firewall column bracket bolts – leave those in place and tight.
   • Remove the under-column plastic trim piece where the column meets the dash frame by removing 4 phillips screws.
   • Remove the two forward column mounting nuts and one rearward column mounting bolt (all are 7/16”). NOTE: Distinguish these two nuts and one bolt from the three column bracket bolts – those attach the column to the supporting bracket and removal of those gains you nothing.
   • With all these mounting fasteners loosened/removed, the steering column will drop just a a little, but far enough to permit easier removal and reinstallation of the bezel/cluster assembly. I have found that temporarily supporting the column in this dropped position to not be necessary, but certainly do so with some scrap wire or twine if you like.
5. Remove the seven stainless phillips screws that mount the bezel/cluster to the dash frame (4 on top, 3 on the bottom).
6. Disconnect the headlight switch from the bezel:
   • Reach up under the dash, again from the driver footwell and locate the push release button on the bottom of the headlight switch. Press the button in (up) and gently pull the headlight knob toward you until it activates fully (headlights would be on) and then ultimately comes all the way out and separates from the switch body.
   • Remove the headlight switch bezel nut that connects the headlight switch to the bezel. This is supposed to require a special tool. Yeah right. I used tiny needle nose in the tiny notches that encircle the outer edge of the bezel nut, but a pair of jeweler’s screw drivers on either side of the diameter also works. This allows the headlight switch to be separated from the bezel and hang inside the dash frame.
7. To disconnect the wiper switch from the bezel, remove the wiper switch bezel nut essentially the same way and for the same reason as the headlight switch bezel nut.
8. Now start to carefully roll the bezel forward to gain access to the upper rear of it, while also ensuring that you are not putting any undue strain on it anywhere. NOTE: the rest of this removal process requires patience and trial-and-error type thinking to keep from breaking anything. In my estimation, the Mopar engineers had little concern for removal and repairs when they designed these dash assemblies. There is almost no slack on any wire and almost no room to access or maneuver. Take your time and you will eventually get everything disconnected and the assembly removed without damaging it.
9. If your rallye dash has a flasher switch at the upper left (some do not), either disconnect it from behind, or alternatively leave it connected and do the same operation you did on the headlight and wiper switches (remove the bezel nut and let it hang), whichever is easier.
10. Reach behind the bezel top just a little left of the speedometer and disconnect the 3-wire dash lighting connector (thin black plastic rectangular connector with a red, orange and green wire) from the printed circuit board (PCB) on the top back of the metal cluster housing and (again) let it hang inside the dash frame. This completes the removals/disconnections from the left side of the steering wheel.
11. Continue to carefully roll/reposition the bezel/cluster assembly (primarily forward, but also perhaps toward the right side) in relation to the cavity. You are now trying to get the right side of the assembly as far out of the cavity as it can be without putting any undue strain on anything, with the goal of beginning to work on removals/disconnections from the right side, ultimately working back toward the center.
12. Remove the radio if present.
    • NOTE: Before I even started the dash removal, I yanked out the existing awful DIN stereo and it’s mounting cage, which revealed the extent of the previous owner hackery to my metal dash frame. This is the point where I would normally be removing the original (I wish) knob-style radio (or maybe in your case, thumbwheel-style) from behind and underneath the dash frame (after removing the knobs, front mounting nuts, and rear strap support). That, unfortunately was not an option in my AC car. I noted at this point (while staring at the gaping hole in the bezel and dash frame left by removing the DIN radio) how little room I would have to install my new original looking modern RetroSound radio head unit because of the encroachment of the aftermarket AC installation and the lack of access to the radio cavity from underneath. But that was my problem and hopefully will not be yours.
    • The shorter story here would have been to say that now is a good time to remove your radio if present, lol.
13. NOTE: This car has AC controls. Non-AC cars have similar but slightly different heater controls. Disconnection of either of these units from the bezel is essentially the same. Remove the small square chrome slider knob (or knobs) from the control lever(s) with a 3/32” hex key.
14. Now you need to gain access to and remove the two rear mounting bolts that attach the control assembly to the cluster housing. These bolts can be loosened and removed with a stubby box end 3/8” wrench and/or a small 3/8” socket. I also had to remove a small flat metal “bridge” bracket that seemed to support some of the weight of the controls. It is on the top right of the control assembly and is connected to the controls via the right-side mounting bolt, and to the bezel with a small Philips screw.
15. With the AC controls disconnected and now also hanging inside the dash frame (do not bother to disconnect the cable or cables) and the radio removed, continue to roll the bezel further forward and to the right, if possible, to gain better access the rest of what needs to be disconnected from the center rear of the assembly.
16. Remove the circular multi-wire gauge and lighting connector from the PCB. It is located on the back of the PCB in the center of the 4-gauge cluster.
17. Remove the two heavy gauge wires from the ammeter terminal posts that are toward the top of that same 4-gauge cluster (the wire on upper terminal should be black and the one on the lower and to the left terminal should be red). These are mounted with 3/8” nuts and can be removed with the same tools used to disconnect the AC controls (3/8 stubby wrench and or socket).
18. Now the bezel/cluster assembly should be completely free, and able to be carefully removed by continuing to move it toward the right and out of the passenger door.

Cluster Disassembly, Inspection, and Overhaul:

1. After the assembly is out of the car, move it to a padded workbench for disassembly.
2. Separate the bezel and gauge cluster by removing the seven small mounting screws that hold the cluster housing to the plastic bezel. NOTE: AC clusters (and maybe just heater cars, idk) will sometimes also have a bracket that connects the two that supports the weight of the controls that will need to be removed. Be sure to also remove anything else from the bezel that might prevent separation, specifically the trip knob (if present), headlight switch, and wiper switch if not removed previously.
3. The first thing you will want to do before doing anything else with your gauges is to determine if the factory instrument voltage regulator (IVR) that was built into the fuel gauge in an original setup has been upgraded. If it has not, I would strongly recommend that you do so. Much more information about this can be found by searching the multiple threads that exist on FABO, or just check this one out (LINK).
4. Once the IVR issue has been sorted, bench-test all the gauges with some jumper leads, a power source, and a resistance box (or some loose resistors if you don’t have a resistance box). NOTE: This may sound more difficult and involved than it actually is if you are not electronically inclined, but it really isn’t a big deal. The goal is to simply simulate how the gauges would operate in the car, by supplying them with voltage (on one gauge terminal) and the correct resistances to ground (other gauge terminal), allowing you to simulate the sender signals to the gauges.
   • NOTES: The FUEL, TEMP, and OIL gauges need +5VDC applied at the appropriate power input terminal post, and need a series resistance to ground at the other terminal post to simulate operation.
   • These posts can identified on the TEMP and OIL gauges (as viewed from the rear and upright) as left post=power, and right post=sender (ground through a series resistance). Looking at the rear of the FUEL gauge with it in an upright position, the (UNMODIFIED*) terminal posts are lower left=+12VDC vehicle power, top/center post=+5VDC from the internal voltage regulator (IVR), and lower right=sender (ground through a series resistance).
   • *It is extremely important that you determine whether or not the factory built-in IVR has been modified (disabled) before applying power to ANY of these three gauges. This can be most easily identified by the presence of a discreet (external) solid-state IVR. If none is present, assume the gauge has not been modified and +12V should be applied to the lower left post.
     • Be aware that an unmodified FUEL gauge could very well (some might say probably) have a non-functioning internal IVR, which at best will mean none of the gauges will work (but could still be functional), and at worst, the internal IVR is shorted, and that condition will burn up all three gauges with 12V applied for any length of time. If that is the case it has probably already happened when the cluster was still in the car.
     • You can also verify (or try to verify) the status of the fuel gauge internals by measuring the continuity (resistance) between the 12V input post and the 5V output post. Using a multimeter set to OHMS, measure between the posts. ANY continuity (any ohms value read on the meter) measured between these posts indicates that the internal IVR has not been disabled and that the "points" are closed. An "open" measurement (no continuity) is slightly less conclusive, because it could mean that the internal IVR has not been disabled, but the "points" are open (very unlikely) or that the internal IVR has been intentionally disabled. If you are still unsure, only perform a powered bench test of all three gauges after they have been removed from the housing (meaning they are no longer electrically connected to each other). This will be your best insurance against damaging all three of them with a misstep.
   • If all three gauges are still mounted to the PCB (have not yet been individually removed), then they are all connected via a PCB trace to the top center post of the FUEL gauge (follow the trace on the PCB for a visual). If the FUEL gauge has been modified, the 12V post is essentially a non-factor (the internal points-style connection between the left post and the top/center post has been cut) and you can simply supply +5VDC to the top/center post and test all three gauges one at a time.
   • If you are unsure about any of the above, it is safest to remove all three gauges from the cluster PCB and test them individually. Please message me or comment in the DISCUSSION tab if you have questions.
   • The series resistance values to ground you will need to test each of the three gauges are (be as precise as you can reasonably be with these values, but a little slop is fine):
     • LOW/EMPTY = 73.7 ohms
     • MID/HALF = 23.0 ohms
     • HIGH/FULL = 10.2 ohms
   • Final NOTE: I didn't want to bog down any further with any more specifics about this process. Please feel free to private message me or comment if you need some guidance.
5. I record what I observe on all the gauge displays with FULL, MID, and LOW signals applied for future reference.
6. Remove and refurbish/replace (as applicable to your project) any non-functioning gauges, tach, and/or speedometer. NOTE: It is a good idea at this stage to also clean and or refurbish/replace the gauge lenses that are typically “melted” in place in the bezel (at least I think the factory installed them with heat, probably a soldering iron). Clean them with a gentle polish made for clear plastic (Meguiar’s makes one). The lenses are extremely susceptible to scratching, so be forewarned that you can expect varying degrees of success with rehabilitation. This is another thing that is somewhat beyond the scope of this tutorial. Message me if you want to.
7. I installed the new printed circuit boards (PCBs) on the back of the cluster housing (LINK). Yours may be fine with just some cleanup. All gauges must be removed to replace the PCBs. Be careful not to lift or otherwise damage the copper traces and pins. Electronics cleaning spray and microfiber cloths work well for this. Re-soldering loose or broken pins is an option, but the new replacements are affordable and will probably save you some headaches.
8. I installed and bench tested new LED bulbs into the cluster housing after sorting out any gauge issues and reinstalling all of them. NOTE: LEDs are polarity sensitive and must be bench tested to verify that they are installed correctly and work before you put the cluster back into the car. Pay special attention to the BRAKE warning lamp when you bench test it, to ensure you have the correct polarity, because BRAKE is the only indicator that has two discreet connections (all other indicators only have a +VDC feed and get their ground from the cluster housing). Again, you need to ensure you have all bulbs oriented correctly in the sockets for them to work in the car. The BRAKE FEED (pin D) is positive and the BRAKE SEND (pin F) is negative.
   
   • 
9. There are many ways you can rehabilitate a worn looking bezel that are not difficult or particularly expensive. Overlays are available and affordable and can make most of the surfaces easily look brand new. New lenses are available, but pricey. The trickiest parts of rehabbing a bezel are the areas that were originally "chromed plastic". But patience and some good masking and spray painting can work wonders. Some argent silver paint on areas that would typically be chrome will make most people happy. Again, this is as about as much detail on this part of the project as I want to include here. I'm happy to answer any questions I can via the DISCUSSION tab or a private message.
10. Once you are satisfied that everything is working properly and looks the way you want it to, reassemble the cluster housing to the bezel. Be extra careful of the trip knob (if present). That is what you should use to orient them together. Don’t force anything and make sure all of the mounting holes are correctly aligned before you reinstall any of them. The plastic holes that the screws thread into are extremely easy to strip or ‘hog out’ if you are not careful.

Bezel/Cluster Reinstallation:
NOTE: Reinstalling the bezel/cluster is essentially the reverse of removal, but here are a few hopefully helpful notes/tips:

1. I installed new screw capture clips in the metal dash frame to receive the bezel mounting screws. I have found that the originals are many times missing or have been hogged out and it is just a good idea to rehab just about anything you can think of before reassembly.
2. I also replaced both factory flashers with grounded LED compatible flashers. This is only necessary if you are also upgrading your exterior lighting to LEDs. If you skip this, the factory flashers will not work properly. If you are only upgrading your dash bulbs, you will not require new flashers. If you do install some (even as just a future provision), they should have a ground lead that will need good, secure grounding to work properly. The hazard flasher should be up inside the dash frame near the fuse block (to the left of the steering column near the headlight switch). I grounded mine to an invisible area on the bottom of the dash frame with a screw. The turns flasher should be underneath the glove box and can be easily grounded the same way.
3. I struggled for several hours trying to reconnect everything to the bezel/cluster and fit it into the frame. I also managed to chew up a lot of the paintwork on the lower bezel veneers and trim, primarily due to the existing hackery that had been done to my metal dash frame by a previous owner when they installed the DIN-mounted stereo. Hopefully none of that will be an issue for you, but my point in mentioning all of this is that you cannot be too careful or too patient when reinstalling the assembly. Take your time and do not force anything back together. If it is not fitting, there is a reason, and it needs to be corrected. Ensure good connections. If you replaced your PCBs, you will likely find that the circular connector will not seat as well as it did originally, due to slightly thicker pins. This is normal and only connecting them as far as they will reasonably go together is fine. I have never had the connector come loose later on.
4. I also installed an LED replacement bulb in the glove box light socket.
5. I utilized the factory flasher switch in the ’67 bezel (not needed for ’71 with a column-mounted flasher switch) to operate the line-lock. There are many other possible options for using this switch if you have a similar scenario.
6. Reinstall the AC/Heater control slider knob(s) and the heater and wiper switch bezel nuts and knobs.
7. Reinstall the radio if applicable.
8. Once you have everything connected and the bezel/cluster assembly resting back in place, but not yet secured with screws, reconnect the battery and do a full system check to ensure everything is working and there is no interference happening inside the cavity (be sure to check that the wipers are not hitting anything when they are moving).
9. Don't forget to reconnect the speedometer cable and re-secure the steering column and trim.
10. Reinstall the seven bezel mounting screws and go for a drive.

**AS ORIGINALLY POSTED**
So this is not your typical how-to. It started out as me keeping project notes for myself, and gradually morphed into something much more as the project progressed (and regressed) and detoured (and derailed) during the six weeks it took me to finish it. It took that long because my barn time is typically limited to weekends when I don't have other commitments, as I still work full time and also support my wife with her ceramic art sales on many weekends this time of year. All that said, it took WAY LONGER than I ever imagined it would and was chock full of whack-a-mole after whack-a-mole issues that fought me at almost every step along the way. The resulting document became almost a mental health diary for me by the end, and probably reads as such. I may do a proper how-to once I am no longer in the post-project stupor because I took a TON of pics along the way. For now, I am posting this just to do something with it, and in hopes that someone out there somewhere might get some useful information from it if they are ever presented with similar challenges. Be forewarned that I did my best to go through it quickly at the end and tried to make it cogent for the average reader and I also tried to remove any offensive language (and believe me, there was a lot of that in there at certain points along the way, lol), but I am not going to guarantee it is perfect. It also has more information than anyone but me will ever want to know, so please be aware of that as you read through it and skip past the parts that may seem like irrelevant babbling. ;) I also posted a how-to that is in a more normal format when I did a similar project on my '67 Barracuda. That more easily readable article can be found here: Step-by-Step '67 Rallye Gauge Cluster Overhaul/Audio System Upgrade

I started with a car that had come to me with an aftermarket (but surprisingly factory looking) AC system, that was and continues to be ALWAYS in the way of every damn thing I need to get to. It also had a shabby, crappy sounding Kenwood DIN mount CD player installed by some hack who nearly destroyed the rallye bezel and the underlying sheet metal of the dash frame in the radio area. I had procured a '67 rallye dash bezel that needed some love, but was otherwise unmolested. The '67 having a flasher switch in the bezel (where a '71 already has a column mounted flasher switch) turned out to be a bonus, because I was able to replace the hidden line-lock toggle switch with the factory looking (but also camouflaged) switch. The '67 to '71 swap also caused a few other challenges too, but nothing insurmountable. One last thing I should mention is that none (and I mean not one) of the dash lights or indicators worked when I got the car. I upgraded all the interior lighting to LEDs and intend to do the same for the exterior when I've had a chance to catch my breath a bit and actually have some fun driving the car for a change.

Anyway, here is a link to the document. It is a PDF made shareable from my One Drive that I swear is benign and without any security risks. I hope that is allowed because I really don't want to even think about trying to copy-and-paste the thing right now. It is probably much easier to view it on a PC instead of a phone.
Enjoy it if you can (and if you have a little patience).


And here are a few pics that show what I started with and the end result.

BEFORE








AFTER