65 Barracuda gauge problems

I just aquired a 65 plymouth barracuda recently, 273 auto,904 presumably. Engine has been mildly built and runs really strong. I LOVE THIS CAR! She is my baby! Anyways, I am having an issue with the fuel and temp gauges. They do not work. Gauge reads empty and I just filled it up, and temp never comes off cold. I have done some fairly extensive research and found out that a common problem is the voltage limiter for the gauges. I replaced with a new one(aftermarket), and still no gauges. I was thinking it would be a sending unit problem but the temp gauge also does not work. I have a wiring schematic on the car and located the wire from the sending unit but havnt tested it yet. I'm thinking it uses resistance to operate the gauge but im not all that familiar with this kind of troubleshooting. I did use my testlight and check the limiter for power and Its not showing any. Neither is the actual plug in wells on the printed curcuit. I checked the harness to the cluster unplugged and have one wire with power. But when plugged in I have power through several wires. Any help on testing the fuel gauge sending unit wire or troubleshooting the gauge cluster would be much appreciated! Thanks everyone! I will also post pictures of the car as soon as I figure out how to uploadd them to the site(I'm new here)!:banghead:

I have been through this battle with my 65 formula s. rebuilt car and much restoration work ongoing to car. When doing the restoration car was on turn style lift upsidedown and went over completly as far a rust and mechanical work. We took off the gas tank, trans, repaired both floor metal units for example. Replaced the gas tank sending unit when replacing it and it when put back together still wants to read empty all the time. I was very dissapointed for sure. It will actually some times move up to half a tank but seems to only do it once and awhile? I was very frustrated with it, but gave up and keep a note pad and write down miles when filling it and keep track to refill gas tank. I also fight the battle with other guages as the speedometer will wiggle all over the place when driving sometimes being close to real speed, but not keeping track so good as it will go up hard when speeding up or slowing down. It can be very frustraiting. I also have a rare rpm guage that is original dealer installed for my Formula S model. It is not hooked up at this time to the now 318 in the car. I plan to redo total electrical system down the road soon probably nex fall/winter with a kit you get as the early a body has a simple system lights, guages, and can be done yourself, I did my 66 cuda many years ago with the same kit. It also goes with the electronic ignition upgrade I currently have installed! It is frustrating as driving at night you have no interior lights on the dash even though all my headlights and tail lights work just fine! I just say dont sweat the small stuff for now and will redo the old wires as they are worn out and fuse set ect a mess! It all is old and needs to be replaced as is typical in such a vehicle. Unless it is a perfect restoration, one should do a restortion to modernality and upgrade. Check here I do not remember the name of the company who sells the kit , but it fits exactly our a body Barracuda's. and simple to put in, with box, wires, ect, few hundred bucks and new car preformance! I am saving now to do it again!

65Cudalover!

Thanks for the input. My gas gauge hasn't moved in the 3 weeks ive owned the car. I have filled it a couple of times. I'm wondering if its the actual instrument cluster thats bad but just not sure. I will keep digging!

Have you tried grounding the wire to the sending unit and see if fuel gauge goes to full? This will tell you if its the sending unit or the gauge.

The instrument panel will not function while dangling from the harness connectors unless you add/supply a chassis ground. A ground through a test light would show power in and out of the limiter and other circuits too but they still wouldn't function.
Hope this helps.

in my 66 (its different than yours, but similar) the pins (two sets of 4) that are integrated with the printed board over years of vibration tend to get fragile and separate from the board itself, mine had this problem. I ended up using sections of paperclips through the hollow pins to hold them straight to the board, and re-soldered them to the printed circuits, used Q-bond (a superglue that can be used with filling powders) at the base of the pins to add strength so this problem wouldnt happen again. sofar so good!

Im not exactly what pins we are referring to. The limiter is a 3 blade male plug in. And the pins for the wiring harness has about 10 pins on it. There is a ground wire that goes from the printed circuit board to the metal frame that the steering column bolts to. I dont think its factory from what I can tell. I will take some photos of the back of the cluster so I can give you a better idea of what everything looks like. There is alot of slop in the limiter when its plugged in to the board and no power flowing through it that I can tell. My test light did not light up when I checked it.

I assume you bought one of the electronic regulators ($30 on ebay). It sounds like it may not be working (probably not installed correctly), but not positive since it sounds like you are using a 12 V test lamp instead of a multimeter (cheap or free at Harbor Freight). The Vreg should put out 5 V, which may not light your tester. Also, as mentioned, the case of the dash cluster must have a jumper wire to ground.

Did you follow the instructions with photos for installing the new Vreg? You must open the fuel gage to get at the factory one and slip heat shrink over the wire wound arm to disable it. At least, I did in my 65 Dart. Your fish may have the rallye dash with tachometer and may be different, but I recall still inside the fuel gage, indeed even in cars up to ~1972 with the rallye dash.

Until you get 5 V on the Vreg output, neither your fuel nor temp gages will work. As I recall, it comes out on the spring finger that sticks off the circuit board, where the copper stud from the fuel gage protrudes.

I did buy the regulator off ebay. Used 12v test light on the vreg when plugged into back of cluster and didnt get a light on test light. I did this assuming 12v would have to pass through vreg and 5v would come out. Is there gonna be a 2nd vreg inside the gas gauge? I replace what i thought was the vreg on the back of the cluster. I also have the cluster grounded to the steering column mount, this is the way it was grounded when I took it apart. The cluster was never dangling from the harness. It was supported on the column and was tested mounted on dash afer limiter installation. I saved some front and back ppictures of a cluster for sale on ebay, and forgive me if the owner of that cluster is a member here. I simply used the pictures as reference. I need all the help I can get. The cluster in these photos is identical to mine. The only difference I see is that this cluster has a grounded condensor(kinda like the kind you see with ignition points) wired to the limiter. Mine doesnt have the condensor or is missing it, and this could be the very culprit keeping my gauges from working. Thank you to everyone here. This is very frustrating!

OK, What looks like a condenser is a noise suppresion cap' . The original limiters mechanical points would make a pop noise in radio speaker. Since a solid state regulator doesn't make a pop noise , you wouldn't need the cap' . I dont know what you bought so... Anyway, There is one small problem. That little black wire on the cap' had a male spade terminal that was poked into the contact slot along with the male spade on the limiter. Delete the one and you have a loose fit and probable lost connection.
There are members here that will tell you to solder those female contacts in the boards to the copper foil on the boards, and that fine I suppose.
Bottom line, what you have right now is loose connections.
There have been cases where poking around with a tester showed it working and once installed it didn't work.
There is one solid state limiter that comes with ring terminals and 3 small screws to attach them at those slots to solve these issues for the end user.
Some vendors just sell parts. Others promote happy moparing whether that includes selling a part or not. Good luck

I always test the installed regulators on the bench using a power supply before installing the whole dash unit. I also test all lights and clean or solder any loose connections. Even when doing all that I install the dash and I still get that one bulb that won't work... kind of pisses me off.

That's why we like photos. Your rallye cluster (w/ tachometer) is totally different than my 65 Dart's. If the rectangular can Vreg is factory, then I am even more confused. I thought those only started ~1967 in regular clusters and not until ~1972 in rallye clusters. However, your fuel gage connectors look totally different than mine, so the Vreg was probably not in there.

First, get a multimeter and measure the Vreg output. If you decide to replace it, I suggest getting an electronic one, which are affordable and much better. Yours looks like an original "thermo-electric" type that pulses on and off to give an average 5 V output.

Ok everyone, Because of the ridiculous amounts of snow we got here in Kansa slowed me down in making progress in my tracking down of the problem I am having with my gauges on my 65 cuda. This is the stock setup cluster, not the rallye. I pulled the cluster out of the car today and dissasemled it What I found is a bad spot on the printed circuit board. Not sure if its repairable. Hopefully someone out here can help me in this. I am pretty sure this is the problem. I am including the pictures of what I have found. The bad spot is in the middle of the pins where the main harness plugs into the cluster. The bad spot is one of the copper foil pathways that carries current to the gauges and dashlights. The foil pathway appears to lead to the output side of the limiter plug in spot. Can you guys study the pictures and maybe throw in your opinion as to whether this is the whole reason I have no fuel or temp gauge. Also, I would like to test the gauges to see if they are fried or not. Im assumong this is done with performing an ohms test. Does anyone have those numbers? Thats for the help everyone!

Bill

P.S. In the last post I proof read(after I posted the thread)and realized that I mis spelled some words. I really am not grammatically challenged, LOL. However, I am not the best typer. Just wanted to clarify!


Bill

You could patch that trace to complete the 12 volt path to that center post or just splice in a wire from the wire in the harness connector to the wire of noise supression capacitor which is also in that center slot.
You would leave all other original connections intact so 12 volts would still go the the pin on the board.
Just keep in mind that copper trace was weak there to serve as a fusible ( weakest link ). Could still be a fault other than the original limiter and capacitor.
Check your gauges for 20 ohms across.

That's so easy to fix it's a crime

Just get a scrap piece of insulated wire, just about anything from 14 to 18ga, and follow the trace, under the blue, out to the "fat" areas on each side. Take a sharp flat screwdriver, knife, etc, and scrape an area down to clean copper.

Make sure the wire is stripped to clean copper (IE not old corroded wire) and "tin" the wire with your iron and solder

"Tin" the copper you scraped clean, then just take needle nose, etc, and solder the wire down to the scraped areas.

Before you fix it, make sure it is really broken. Use an ohmeter from that pin to the Vreg terminal. It looks like the copper trace just lifted a bit, maybe from heat, but is still intact. These circuit boards are amazingly simple to follow and repair. Anybody that understands V=IR can understand one. You should see what people deal with at companies where I have worked, with tiny surface mount chips and traces you can barely see (like on a PC motherboard).

Update!!!

Sorry everyone for the hiatus! I soldered a piece of single strand 18 ga wire to the trace and covered it with some liquid electrical tape. I reassembled the cluster and low and behold, I have gauges. Or at least a gas gauge! When I turned the key and monitored the gauges I noticed the temp gauge pegged out to hot, and i hadn't even started the car yet. Five minutes later I seen magic smoke behind the gauges and then the temp gauge went back to cold and hasn't moved since. I would like to install an aftermarket triple pod gauge cluster for it. I would like to personally thank everyone for your insight on this issue. It has been very frustrating and finally we tackled it!

Thanks!

Bill