Three dead gauges, FUEL TEMP OIL

[rikubot]

Hello you beautiful people.

I am having an issue with my fuel, temp, and oil pressure gauges. I have tested them AND the circuit board outside of the dash, and they seemed to work. The bulbs lit up, and the gauges went to 3/4 full when juiced with 2 double A batteries. I got a brand-spankin' new dash harness from M&K in there, and a new engine harness as well. Oh, and a BRAND NEW solid state voltage regulator from RT-Engineering. I am about 85% sure the sending units work, as they did before I operated on my dash and did a triple bypass surgery with the new harness. I snipped out some of the worst home-made wiring known to man. Any guesses or advice is very much appreciated. Am I missing something? Should I just buy new senders for temp and oil? I can't think of anything else it would be. Can I test my senders? Also, there's a wiring coming out of my fuel sender that isn't attached to anything, is this the ground? If so, where do I bolt it? Let me hear your thoughts!

-Mike

[XH29N0G]

Someone on here will be able to tell, but I bet there are ways to check the temp and oil senders before buying new ones.  I have not looked into how they work, but it could have to do with resistance and this would be possible to test with an ohm meter.  The main reason I responded was to mention that if you do not have a factory service manual or a wiring diagram, that you probably want to get one and trace out the various wires.  I never traced out wires until having this car, and while it takes patience, it really helps in diagnosing these sorts of problems.  

[69wannabe]

Sounds like you instrument cluster voltage regulator bit the dust. Mine died a couple of year's back and I was able to replace it on the back of the cluster without removing the whole cluster. Actually you may be better of to replace it with a new solid state instrument voltage regulator/limiter. There is a way to check it to see if it is good or bad when you get it off the cluster but I haven't checked one in so long I don't remember how to check it. I have a few of these in a drawer out in my shop if your's is bad but they are like the original style. Maybe Pete will chime in and post how to check it so you can check it and see what you got and so I can check the one's I got and see if they are any good or not. I can send you one of these if you need it but like I said earlier it may be a good time to upgrade to a solid state style one. 

[rikubot]

Sounds like you instrument cluster voltage regulator bit the dust. Mine died a couple of year's back and I was able to replace it on the back of the cluster without removing the whole cluster. Actually you may be better of to replace it with a new solid state instrument voltage regulator/limiter. There is a way to check it to see if it is good or bad when you get it off the cluster but I haven't checked one in so long I don't remember how to check it. I have a few of these in a drawer out in my shop if your's is bad but they are like the original style. Maybe Pete will chime in and post how to check it so you can check it and see what you got and so I can check the one's I got and see if they are any good or not. I can send you one of these if you need it but like I said earlier it may be a good time to upgrade to a solid state style one. 

Thank you very much Wannabe I really appreciate the offer. That's what my first thinking was too, so I went ahead and got that new Solid State regulator. I was 99% sure I had my issue pinned to that regulator and I got the new one in the mail today, installed it, and boom, same place as before but out $60. I'm still glad I bought it, but I'm going crazy not knowing why they still don't work.

[A383Wing]

wondering if you have a bad pin on the printed circuit board

[rikubot]

Someone on here will be able to tell, but I bet there are ways to check the temp and oil senders before buying new ones.  I have not looked into how they work, but it could have to do with resistance and this would be possible to test with an ohm meter.  The main reason I responded was to mention that if you do not have a factory service manual or a wiring diagram, that you probably want to get one and trace out the various wires.  I never traces out wires until having this car, and while it takes patience, it really helps in diagnosing these sorts of problems. 

XH,

Yes sir, I can't live without them right now haha. The service manual says "faulty voltage limiter" or "open circuit on battery side (input of limiter)" if I have the three dead gauges. Seems the black 12v feed wire is powering the limiter as the red indicator light is blinking when ignition is turned on. I find it pretty hard to believe all three senders don't work (they worked before), so the lack of function blows my mind. Damn near has me watching the Kardashians to punish myself. I read that the gauges are slow to read in these old cars, so about how long do they take to show levels? What could the "open circuit on battery side" be? I have a brand new engine harness plugged into a brand new dash harness, plugged into a tested circuit board and tested gauges, with a brand new solid state voltage limiter. WHAT AM I MISSING? IT'S DEVIL VOODOO I TELL YA!!!!

Thanks for the help Mopar Bro

[Dino]

The solid state regulator is a must, don't worry about that part anymore.  I had all 3 gauges fry when my stock limiter died about 2 hours after installing my restored cluster, not fun.

The gauges work and the likely hood of all senders to be dead is pretty slim.  Either the pins on the circut board are not what they used to be, or there's no power going to the board.  I'd solder the pins to the board first EVEN if it tested out okay on the bench.  Mine did the same.  Eventually I ran out of options, cleaned the board again, and spent a few minutes soldering.  Haven't had a problem since.

Where's this wire coming out of the fuel sender exactly?  One wire should attach to the little rod on the sender itself.  The ground is a clamp that goes from the sender to the metal fuel line by bridging the rubber hose.

Gauuges start moving within two seconds.  You have the cluster grounded to the dash frame right?

[rikubot]

wondering if you have a bad pin on the printed circuit board

I like how you're thinking, however I did check the pins for each separate gauge using the two AA battery trick, so I figured those three were cool. The black 12v feed coming from the harness I checked with a makeshift test light, and the new IVR4 Voltage Limiter has a lil' red light that blinks when it's working (assuming meaning it's getting the 12v feed from the circuit board), so I figure its pin is working as well. The pin that runs the lights worked as well, although it's not real important right now.

[Dino]

wondering if you have a bad pin on the printed circuit board

I like how you're thinking, however I did check the pins for each separate gauge using the two AA battery trick, so I figured those three were cool. The black 12v feed coming from the harness I checked with a makeshift test light, and the new IVR4 Voltage Limiter has a lil' red light that blinks when it's working (assuming meaning it's getting the 12v feed from the circuit board), so I figure its pin is working as well. The pin that runs the lights worked as well, although it's not real important right now.

That's how it was on mine, all tested fine on the bench yet once the heavy connector was pushed into place, different story.

[rikubot]

The solid state regulator is a must, don't worry about that part anymore.  I had all 3 gauges fry when my stock limiter died about 2 hours after installing my restored cluster, not fun.

The gauges work and the likely hood of all senders to be dead is pretty slim.  Either the pins on the circut board are not what they used to be, or there's no power going to the board.  I'd solder the pins to the board first EVEN if it tested out okay on the bench.  Mine did the same.  Eventually I ran out of options, cleaned the board again, and spent a few minutes soldering.  Haven't had a problem since.

Where's this wire coming out of the fuel sender exactly?  One wire should attach to the little rod on the sender itself.  The ground is a clamp that goes from the sender to the metal fuel line by bridging the rubber hose.

Gauuges start moving within two seconds.  You have the cluster grounded to the dash frame right?

Next time I pull the cluster out I'll be soldering those pins. I don't want to chance it. Tell me if I'm right in thinking that the power to the circuit is good if the red light on IVR4 is blinking? This is where I get VERY confused. The 12v power definitely IS coming from the black wire, it lit my lil #57 bulb up pretty good. I made a test light out of an old turn signal bulb and socket. Seems to work ok.  

The wire looks like it's coming out of the hole where the fuel line is coming out. I'll get a picture tomorrow in the daylight. That whole area on my car is pretty molested and I have a hard time making it right with nothing to look at. I recently pulled a non-working electric pump off it and had to franken-hose my fuel line. And yes sir, cluster is grounded.

[Dino]

Yes the blinking led indicates power to the IVR.  That doesn't mean it's sending it to the gauges though.

I'd love to see a picture of that fuel sender wire.   

[rikubot]

Yes the blinking led indicates power to the IVR.  That doesn't mean it's sending it to the gauges though.

I'd love to see a picture of that fuel sender wire.   

Dang it, you're right. So that could mean that the little copper thing that the bottom pin of the regulator plugs into may not be making contact with the board. I knew I should have pulled those, cleaned the contacts, and put a little dielectric grease on 'em. Maybe even dropped some solder on em. Do I need flux for that? I have a hard time with solder cuz my gun is crap.

Ok I will get a good photo of that area ASAP. I know the ground has been tinkered with because the end loop thing looks fairly new and colored like the aftermarket ones.

[Dino]

Careful with those big solder guns.  You may just want to pick up a Harbor Freight or Lowes solder iron for this, its cheap and will do the job.  Just make sure you tin the tip first.  Yes use flux unless the solder itself has flux in it.  Make sure the pins are snug, I was able to twist one or two on mine and they snugged right up.  Make sure the board is clean and solder away.  Do not spend more than a few seconds on each pin.  If the solder doesn't flow it's a gun issue, don't fry the board.  Solder both sides and you'll be good to go.  There's good videos on youtube to do small electronics soldering if you need them.

[rikubot]

I've got a little 30 watt thing I got from wal mart when my Xbox needed a new disc drive. It doesn't work great but it should get the job done. Once I get that all soldered up and it doesn't work, I'm totally out of ideas. Then I'm just gonna have to try sweet talkin' to her under a full moon haha

[rikubot]

And I want to add that I really appreciate your help Dino! I see you on here a lot helping people out and its pretty damn cool. Thanks again good sir 

[Dino]

My pleasure.  It would probably be better if I actually knew what he heck I was talking about.   

[rikubot]

Haha you sure could have fooled me! "Fake it til you make it!"

[rikubot]

I just thought of some possibly valuable information: One of the tabs where my cluster bolts to the dash has been cut off the dash itself to make room for the abomination that was my old gauge set. Its the tab that the top right screw goes into on the cluster. When I mount it up, I screw in all four remaining screws. Do you think this would need to be there to ground my cluster completely? I wouldn't think so because the turn indicators work but I just wanted to hear everyone's thoughts. It IS in the area of my problem.

[Dino]

Although you could have a bad ground, one screw through the frame should do it.  When in doubt add a lead wth alligator clips for testing.  Just make sure the ground is on clean metal.

[rikubot]

I got up under the car this morning to take a pic of that wire coming out of the tank. It looks like it is coming out of the same hole as the fuel line. Its flat, then is spliced into traditional insulated wire. Also, I just had a thought, If the sending units were the problem, wouldn't the gauges be pegged all the way up? Especially if the gauges were getting power from the 5v feed out of the regulator? Don't the senders give off a signal based off resistance? Or at least doesn't the fuel sender?

Sorry the pic is terrible. Iphone 4.

[rikubot]

Here's the end of the wire coming out of my fuel sending unit.

[Bronzedodge]

Something is odd there.  The 1st pic looks like the ground strap, which should bridge the short rubber line from the pickup.  Something wrong with your ground strap perhaps?   

[Dino]

Yep, first pic is the ground strap but it's really short and you have a ot of rubber hose there for some reason.  It looks like they just bridged al that with a wire. Without that ground the gauge would not work.  It's a bit messy and redoing it would not be a bad idea, but in essence it should do the job.

[rikubot]

Thanks guys, I knew something was fishy.

What happened was someone had installed an electric fuel pump there, and it quit working, so I pulled the sucker off. I used rubber hose to patch the missing fuel line (didn't know any better). So should I just clamp that ground strap to the fuel line? Or bolt it to the body?

[Pete in NH]

Thanks guys, I knew something was fishy.

What happened was someone had installed an electric fuel pump there, and it quit working, so I pulled the sucker off. I used rubber hose to patch the missing fuel line (didn't know any better). So should I just clamp that ground strap to the fuel line? Or bolt it to the body?

Tie wrapping the wire terminal to the fuel line isn't really going to work. You want to run a wire from the sending unit metal to the body ground itself. I would use something nice and flexible like a piece of ground braid.

The factory used a metal strap with a clip on either end that bridged the rubber fuel line section and then depended on the fuel line mounting clips into the frame for a ground. A direct ground would be more reliable.

Also, I would ground that "tab" you talked about a few posts back on the one mounting screw of the dash printed circuit board. It can't hurt and might be your problem of the three gauges not working. Bad connections between the pins on the circuit board connector and the circuit board foil as mentioned is also a common problem.

[rikubot]

I'll bolt that wire to the body today. I still need to solder my pins to the board as well. I did have a nice surprise last night. I got bored and went to go start up my car, so of course I started playing with switches. I noticed a tiny little glow on my gauges when I put the headlights on. So I started messing with the dimmer. Low and behold, I have backlights to all six of my gauges! I about had a heart attack. I've never seen real Charger gauges lit up, and although it was pretty dim, it looked so cool! I did find a sweet spot toward the top of the dim setting where they are bright enough to read with ease. My dimmer switch is dodgy as it gets but I'm just happy it sorta works, and now I can see my dead gauges at night haha. 

I'll go tie up that ground right now...

[Dino]

Some leds in that cluster will really give you a heart attack!   

I'm not a big fan of leds but in the dash they are right at home.  Just leave the turn signal indicators and high beam indicator stock, they don't need leds.

[68charger440]

I will give a third nod to make sure that the cluster is grounded.  I have seen that cause similar problems before even though you would swear it was grounded.  The aligator clips on a wire to both the cluster and a ground is sure a quick and easy test just to be sure.

[rikubot]

Some leds in that cluster will really give you a heart attack!   

I'm not a big fan of leds but in the dash they are right at home.  Just leave the turn signal indicators and high beam indicator stock, they don't need leds.

I REALLY want to do LEDs on the backlighting. I saw a post on here where someone did theirs and it was more blueish and looked great. I thought I faved the page but I must not have. What about the brake warning light? It seems bright enough already. Also, what kind of LEDs did you use, and do I need to do anything else to my electrical system or just plug them in?

[rikubot]

I will give a third nod to make sure that the cluster is grounded.  I have seen that cause similar problems before even though you would swear it was grounded.  The aligator clips on a wire to both the cluster and a ground is sure a quick and easy test just to be sure.

Will do my friend. This is the ONLY thing left to do so it HAS to work!

[rikubot]

Here's a strange happening: I bolted that ground to the trunk floor, replaced some taillight bulbs, and now I don't have ignition? Started up just great last night...?

[68charger440]

Here's a strange happening: I bolted that ground to the trunk floor, replaced some taillight bulbs, and now I don't have ignition? Started up just great last night...?

These electrical systems were weak when they were brand new, add 45 plus years and new power sucking gadgets to the mix and nightmares happen.  Do you have a copy of the wiring schematic?  If not you need to get one.  Search on line and you can find them.  What do you mean you don't have ignition?  Does it turn but not start, or do you have nothing at all?  Might be time to break out the multimeter.

[rikubot]

It turned out to be a tired positive battery cable...again. I've had troubles with it before that I thought I fixed but it just needs to be replaced. Yes sir thanks for the tip. I do have most of the wiring schematics on my computer. They are my Bible for the time being. I have noticed a few inconsistencies in a couple of them but for the most part they are a Godsend. I would just get a little "click" sound. I messed with a few things and now she starts up. I definitely need new cables in the near future.

I do have a little good news. My dome light is working now, and the dimmer will even activate it! My car fixes itself! Christine, anyone? 

[rikubot]

I have a little update:

I grounded out the corner of the bezel that had no tab to bolt to and still nada. I did finally get most of my interior lights working, though. I strung up a map harness based off of some pictures and got my key light and time relay to work. Still, the map light didn't work. Not sure why, I built up my harness just like in the pictures and tied it into the fuse box. Maybe a bad wire? The bulb is good    

I did take her for a cruise the other night and the headlamps and interior lights did great. The dome light popped on once because I have my dimmer all the way to the top to make the lights brighter and it must have just made contact to turn on. I've just about got my wiring figured out. Just need to figure out gauges, wiper motor, map light, washer squirter. You guys have been such a tremendous help!  

Edit: The air and heating lights also do not work when I plug the wire into the three prong plug coming off the main harness...