Hello! Here's the situation. Neither the temp or fuel gauge on my '65 Fury III worked when I got the car. I finally dug into it a few days ago, but have not had success. Here's a summary of where I am without going into excruciating detail about all the hours I've spend on trying to get these gauges to work. When I started, neither gauge worked... First, I pulled the gauge pod and gently sanded all of the contacts on the printed circuit board, re-soldered the 4 pins on the board for the socket connector, gently sanded the pins to remove any oxidation, retightened all of the terminals in the socket by slightly crimping/crushing them, wire brushed all of the mounting terminals for each gauge, cleaned each nut, and re***embled everything tightly. When I reinstalled the gauges and turned on the key, both gauges pegged, and the temp gauge started to smoke. I immediately disconnected everything and decided to start with the temp gauge. I read the manual and decided to run some tests. The voltage step-down control in the fuel gauge that feeds the temp gauge jumps between 1 and 7 volts, so it appears as if it works (per the manual). I have continuity through the circuit board to the temp gauge, so I know that the temp gauge is getting current as it should. I disconnected the temp sending unit wire at the water pump and checked for a short in the wire at the socket end, and there was none; no current would p*** through the wire when it was disconnected, and current flowed when it was connected. Lastly, the sending unit showed about 78 ohms with the engine slightly warm. I believe that the resistance range should be 25 - 152, so the unit appears to be working. So...the temp gauge it getting the correct current, there's no short in the wire to the sensing unit on the engine, and the sensing unit appears to be in line. Seems like a bad gauge(?). Onto the fuel gauge. It was getting about 14v through the socket. The wire in the socket going to the gas tank sending unit measured about 72 ohms resistance. I can't find the spec in the manual, but at least I know that it's not infinite resistance. So, I know that the gauge is getting power and it seems as if the sending unit is not bad, although I haven't dropped the tank to test it. Here's the rub...during the 100 or so times I had the gauges out, if I held the gauge pod and tilted it forward, putting some pressure on the harness, they would work...kind of...for 30 seconds or so. The fuel gauge would move to full, or halfway there (I have about half a tank of fuel), and the temp gauge would be to maybe 1/4 hot...then it would go to cold. YES, I had the gauge pod grounded. Sometimes they would work, and sometimes they wouldn't, other times one and not the other. To see if there might have been a break in the harness, I put test lights into the sockets that feed the gauges and gauge lights, jiggled the harness behind the dash, but I still got steady power, so it doesn't appear as if there are any breaks in the harness. NOTE - The car is a fresh repaint, so I also ran new grounds from the neg battery terminal to the frame and to the firewall to ***ure that all parts of the car were grounded. So...I have gauges that "kinda" work when you hold them in a special way. Everything else is seemingly in order. The manual tells how to test the gauges, but they use a special tool that I don't have. I did feel 12V to the power terminal on the fuel gauge, grounded the housing, then grounded the terminal going to the sensor, and the gauge pegged full. Seems like it works??? Any ideas what's going on? I had to walk away for a day 'cause it's frustrating the hell out of me. Thanks... Chris
Try disconnecting any bulkhead connectors where they p*** through the firewall. Check for any signs of corrosion, clean and dry as needed, maybe use a bit of dielectric grease and make sure they lock back together properly when you re***emble.
There is a voltage regulator that drops the voltage from 14 to 6 volts on the gauge cluster. After all these years most of them go bad. All the US car company's used 6 volt gauges until around 1990. You can get a new one from any good parts store? If you are lucky to have one in your area. You can also build a electronic using a IC regulator set to 6 volts. There is a post on how to build one on the ham. If you can not find this go to Google and check. There are many sites that have this mod. Good luck, Ed.
Found a couple links. The second one scroll down until the schematic shows up. There is a parts list also. 1962to1965mopar.ornocar.com chargersourceguide.com\voltagelimiter.HTML Hope this helps, Ed
Clay - Already did that. This is not my first Mopar/C body, and I know that they're notorious for corrosion in the bulkhead fittings. I pulled them apart , cleaned the male and female terminals, and packed them with grease. All seems well. Harvey - Per the factory shop manual, the fuel gauge should have 12v going to it; the fuel gauge has an integral voltage regulator that drops the voltage to around 6 volts before it feeds the temp gauge through the circuit board. I put a test light and a volt meter on the fuel gauge voltage reg output, and test light will flashed/the volt meter jumped around, which, according to the manual, is what should happen. I have the factory manual which has the schematic, but thanks for the link. Anyone else? Chris
The voltage limiter for the temp & fuel guage should have one leg ground, one 12 volts , one pulsing 0 to 5 volts to the two guages . You should have the pulsing voltage at both the fuel sender and temp sending unit, momentary grounding the pulse wire at either sender should raise its guage. Some cases a bad voltage limiter will destroy both guages.
If the voltage to the gauges is correct, and the gauges are grounding properly through the sending units, the gauges are both junk. The fact that you got a temporary reading from them by somersaulting them just right reinforces the fact the gauges are junk. Gene
some mopars, Barracudas from the 60s for instance, the fuel gauge is the dash voltage regulator, others use a small rectangular metal pod with 3 plug ins. which Chris is already aware of. The amp meter is source of most electrical problems in a 60s early 70s mopar, but other than possibly burning the harness up when it goes, or causing a no charge situation, so I don't think that's it. Maybe 50 Dodge 4x4 is right. There are a few 65 Furys in a yard about 20 miles from me if that's what it winds up being. If N.C. has been crushed out.
Gary et. al - Thanks for the replies. The fuel gauge has 3 terminals on the back; 1 has 12v going into it from the socket, one has a copper bridge on it from the circuit board that puts out pulsing voltage and feeds the temp gauge, and one shows pulsing voltage as well. I ***ume that the gauge grounds in the dash through the gauge housing. It appears that all is as it should be as far as the connections and voltage goes. At the moment, I have the temp gauge disconnected at the sensor on the engine. If I connect it, the gauge pegs and will eventually start to smoke like it did the first time. I'm aware of the issues with Mopar amp gauges. It took me a week to figure out the bad amp gauge on my first C body last year, but that was only after burning out 7 sets of headlights because of the unregulated voltage. I already ordered a set of gauges from Skip at French Lake Auto Parts, but I have no idea if they'll be good or not. Randy Routt - I may take you up on your offer if the first set of gauges are no good. Does anyone know if there's a vendor making repop gauges out there? Thanks... Chris
Chris, some time you DO have to walk away from your project.I don't if you remmber my 1956 buick station wagon.My DRINKING WENT UP AND I THOUGHT I WAS GOING TO SMOKE CIGS. AND I DONT EVEN SMOKE.LOL.Just walk away and settle down buddy. It always worked for me. The people are very helpful on this site .They helped me through a lot. Heres before shot.Bruce. .
Bruce - I do recall reading about your ordeal. I think you also chimed in when I was having electrical problems with my first C body. Something so simple shouldn't break your balls as much as it does. I ended up taking this weekend off from the Fury. I have the same post going at www.forcbodiesonly.com, but it gets much less traffic than the HAMB. Hopefully it's just the gauges. Chris
The Jalopy Journal
