1970 300 instrument cluster/voltage limiter R&R???

[challenger]

Hello all, I have a fuel gauge issue that I am trying to remedy. I have removed the sending unit and cleaned it up so it now reads 0-50 ohms. I've read that they read 8-70 ohms but I am thinking what I have is proper. It certainly seems proper and I get the same resistance if I bypass the wiper and read the wire turns alone. I also grounded the wire at the connector behind the front kick panel and the gauge doesn't budge. I removed the voltage limiter and tested it but I cannot see any way to get it back in. There is no way to see how or where I am going as I fell my way around the back of the instrument cluster. I tried a camera, flashlight and everything else I could think of. Am I going to have to take the dash and instrument cluster out in order to reinstall the limiter?
This car gets driven just enough to cause me to have to do a few cursed repairs every Spring as my wife gets the itch to drive it while the temperature is holding steady at 73F +- .5 degrees. Once it gets too hot there is no longer any emergency to drive the car.
This year I am going to get things right and I am going to drive the living sh^& out of it every chance I get. This way the off season gremlins might be slow on the uptake and allow me to enjoy the car for twelve, or more, months straight.
I had the dash out a couple of years ago and this process sucked to be mild. I absolutely do not want to do this again if I can help it. Is there anyone out there that has replaced the voltage limiter without removing the instrument cluster? PLEASE tell me the secret to getting this little SON back in. IF there are othe ideas about the fuel gauge not working I would also greatly appreciate this to say the least.
Many thanks,
Howard
BTW - this is a convertible if this matters.

 

[Big_John]

Here's a pic of the back of the cluster from my 70 300 if that helps.

 

[Davea Lux]

Another thing you may need to check is the circuit board the limiter plugs into, these have been known to short out and burn out the pathway to the gauge. Spiders have also been know to spin their webs inside the cluster panel and lock up the gauge. Unfortunately these items will require the removal of the cluster to check. Another source of gauge failure is the coiled conductor spring at the base of the gauge needle, these have been known to break and leave the gauge inoperative.

Dave

 

[challenger]

Thanks for the help and info. Looks like time to start removing the seats and screws and on and an. People talk about removing the dash like it's a walk in the park. I found it to be a real PIA. Getting it back in was worse due to the ease in which so may wires cam be pinched.
Has ANYONE been able to replace this thing without removing the dash?

 

[Big_John]

Thanks for the help and info. Looks like time to start removing the seats and screws and on and an. People talk about removing the dash like it's a walk in the park. I found it to be a real PIA. Getting it back in was worse due to the ease in which so may wires cam be pinched.
Has ANYONE been able to replace this thing without removing the dash?

There is an alternative... but it still involves getting at the back of the dash.

See the blue wire hanging from the stud on the gas gauge in my pic? That connects to a voltage regulator that is part of the low fuel warning light relay. It was an option and my 70 300 vert has it. There is no plug in limiter in the back of the dash. The relay is over by the passenger ashtray.

So... two things could work for you... Either find a low fuel relay or replace it with something else.

I've seen the low fuel relays on Ebay, but someone figured out that they also fit an E body and the prices went through the roof. Example: Mopar # 2983828 Low Fuel Relay E Body Cuda, Challenger Barracuda

The other option would be this.
TechnoVersions - MeterMatch for Analog Gauge Correction

Scroll down to the Mopar section and you'll it includes a voltage regulator. A friend used one of these and aside from smoking the first one by hooking it up wrong, it's worked well for him. The bonus is you can correct the gauge too.

I would try the second option myself. The hookup would still take getting to the back of the gauge, but it might be easier.

I've had the complete dash out of mine and it's not a job for the faint of heart. I think that this could be done without such drastic measures.

I like to take the seat out for this stuff myself as it lets you get a better angle with your hand and it's easier on your back. Maybe loosen the steering column and let it drop a bit. I assume you've removed the A/C duct and column cover.

 

[challenger]

So far I have removed the a/c ducting and column cover so far. I am leaning to removing the dash as much as I dread the process. I'd rather not deal with the other options.
Thanks for the help BTW.

 

[Big_John]

So far I have removed the a/c ducting and column cover so far. I am leaning to removing the dash as much as I dread the process. I'd rather not deal with the other options.
Thanks for the help BTW.

If you are going to remove the entire dash, You could just unbolt the top, loosen the bottom bolts and pivot it out enough to reach behind it.

 

[Fury Pursuit]

You can install the limiter without removing the dash/cluster etc. You have to have smallish hands and a lot of patience. I used super glue to actually attach the limiter to my finger once.....it worked.

 

[challenger]

Well my hands are big and I can barely touch the back of the instrument cluster so I doubt that I can accomplish this without removing, or tipping down as John mentions, the dash. I'll have to look harder at the tilting idea. I don't readily see how this is done???

 

[Davea Lux]

Once you get the regulator back in, if you still have no gas gauge, try checking the fuse holder for the the instrument cluster for voltage. Sometimes these rust up between the fuse holder and the fuse so that you have a bad connection and no voltage to the gauge. When you hook a test light to the sensor lead to the tank unit you should get a flashing light, this means you have signal to the sensor. This usually means the tank unit is bad could also be that your tank has lost its ground and the sensor does not have a complete circuit to operate. You can try grounding the tank to the frame with a wire and some alligator clips to see if that helps. Feel your big hands pain, I had to have one of my daughters plug the regulator in for me on my 65 Chrysler.

 

[Big_John]

I'll have to look harder at the tilting idea. I don't readily see how this is done???

There are bolts that hold the dash to the top under the windshield and there are bolts right by the door hinges. Take the top ones out and loosen the bottom a couple turns.

The dash can pivot towards you... It helps that it's a convertible so you can stand up to do this.

I was just working on mine... (also a 70 300 vert) and was under the dash. I see the issue. The steering column bracket is right in the way. It would be easy to unbolt the column and see if it will drop down far enough so you can get your hands in there.

 

[challenger]

Thanks for the replies. It just so happens that I removed the drivers seat and dropped the steering wheel down just a few minutes ago. It does offer more room. I was able to put the lamp back in that I took out while fumbling around in my first attempt at getting to the limiter. Now I'll try again to see if I can put the limiter back. It's so tight but I'll try it. I noticed another concern. There is a capacitor mounted back there too. It has a space lug and I am wondering if it is for the limiter? I've read about some cars having capacitors but my FSM doesn't show one. Then again the FSM shows the setup with the low fuel warning option AND with a limiter so it's always up for deciphering. Anyone know if this is for the limiter? If so it will be even more enjoyable trying to get it back in with the limiter .
Until I get more information on that I'll investigate the bolts for tilting the dash.
Thanks again.

 

[challenger]

Never mind on the capacitor. I found out that it plugs in with the middle ignition spade.

 

[challenger]

Sorry to have to ask this but are you talking about the "ACC" fuse? My FSM shows that as the only one feeding the instrument cluster.
Maybe I'm missing something in looking at the electrical schematic in the FSM? I have found that the FSM from this car is lacking compared to other FSMs that I have and it's always the items you need detailed information on that missing or lacking detail.
As for the wiring/circuit I have buzzed out the wire from the sending unit to the connector behind the kick panel. Hooking the meter to the dark blue wire and a nearby ground I get a proper resistance reading so the sending unit and wire to that point are complete and/or functioning.
Thanks

Once you get the regulator back in, if you still have no gas gauge, try checking the fuse holder for the the instrument cluster for voltage. Sometimes these rust up between the fuse holder and the fuse so that you have a bad connection and no voltage to the gauge. When you hook a test light to the sensor lead to the tank unit you should get a flashing light, this means you have signal to the sensor. This usually means the tank unit is bad could also be that your tank has lost its ground and the sensor does not have a complete circuit to operate. You can try grounding the tank to the frame with a wire and some alligator clips to see if that helps. Feel your big hands pain, I had to have one of my daughters plug the regulator in for me on my 65 Chrysler.

 

[Davea Lux]

Sorry to have to ask this but are you talking about the "ACC" fuse? My FSM shows that as the only one feeding the instrument cluster.
Maybe I'm missing something in looking at the electrical schematic in the FSM? I have found that the FSM from this car is lacking compared to other FSMs that I have and it's always the items you need detailed information on that missing or lacking detail.
As for the wiring/circuit I have buzzed out the wire from the sending unit to the connector behind the kick panel. Hooking the meter to the dark blue wire and a nearby ground I get a proper resistance reading so the sending unit and wire to that point are complete and/or functioning.
Thanks

Try hooking a test light to ground and the blue wire, you should get the test light to blink. If there is no power, there is no blink and no signal. Usually there will be about a 2 amp fuse for the gauges although yours might be wired through the ACC.

Dave

 

[challenger]

Try hooking a test light to ground and the blue wire, you should get the test light to blink. If there is no power, there is no blink and no signal. Usually there will be about a 2 amp fuse for the gauges although yours might be wired through the ACC.

Dave

I suspect I'd get a flashing light if the limiter was installed but it isn't right now. I spent the about two hours again today trying to get this damn thing inserted into the pc card but it's hopeless. I have the seat out and I was lying on my back with my head under the dash trying as best as I could to get my hands in position but no way. I'll start removing the instrument cluster later today.
I hooked the limiter up to a 12v battery and used a test light to make sure it flashed out of the car and it does.

 

[Davea Lux]

I suspect I'd get a flashing light if the limiter was installed but it isn't right now. I spent the about two hours again today trying to get this damn thing inserted into the pc card but it's hopeless. I have the seat out and I was lying on my back with my head under the dash trying as best as I could to get my hands in position but no way. I'll start removing the instrument cluster later today.
I hooked the limiter up to a 12v battery and used a test light to make sure it flashed out of the car and it does.

I feel your pain. When you get it re-installed, be sure unplug the sensor lead from the gas tank unit before trying the flash test.

Dave

 

[challenger]

Will do. I'm taking a break from the cluster removal process. I am wondering if I am not better off removing the entire dash board. It's been a long time since I redid the dash in this car. I had the whole dash out and did all the Lettering and clean up but it was over 5 years ago. It may be that the cluster has to come out before the dash board can come out but I don't recall. I've been battling with the heater controls and I am already bleeding.

 

[Polara_500]

Well, heck, if I've been working on a vehicle for 5 minutes and I'm not bleeding it's a special day for me.

 

[challenger]

Well I got it out and it was as much fun as I remember

']

']

[/URL][/URL]
I made a little note almost 7 years ago when I did the "restoration" of the dash never thinking I'd see it again.
This car only has maybe 57,000 miles on it yet still has and had gremlins in the electrical system. Mainly the dash etc. I guess it's par for the course.