Which Fuse Feeds the Gauges (voltage limiter) on '71-74 BBody?

[Dibbons]

Some time ago sent my gauge cluster away to have the ammeter converted to a voltage meter. After installation (with new voltage limiter) everything worked OK. This 1972 Satellite Sebring Plus was "stored" for quite some time while doing an engine swap (318 to 340). Now it's running again with the 340 but none of the gauges work: oil pressure, fuel, coolant (except for the speedo/odometer do function).

First step is finding which fuse feeds the limiter (I ask here only because i'm not the greatest at reading wiring diagrams). Then I'll check for ground, and if necessary pull out the entire instrument cluster (not fun). Thank you.

Good video on the subject I just referenced:

 

[Dibbons]

Update: I found the fuse is the one labelled "ACC' just above the AC/Heater fuse. It was not blown and has power. The fuse is on the right bank of the fuse box, just below the 5 amp fuse.

I crawled under the dash and looked up toward the voltage limiter and much to my surprise found the power source wiring had become unplugged. I plugged it back in, but did not hear or feel anything like a click or any resistance the it just fell off once again. It appears to be factory style rubber-coated 90 degree plug.

I have no idea how I am going to snug up the connection. The power lead is female and the limiter connector is male, both "slick" as can be. I do now seem to remember when I installed the dash the same wire was very loose but I just kept my fingers crossed that it would stay put. My mistake.

Many electrical issues can be near impossible to track down. At least in this case, i found the problem.

 

[Nacho-RT74]

On Standard cluster is one of the top fuses… the one with blue wire on back and divorced from buss bars. It handles RUN (Ign1) circuit. Same fuse feeding also some other devices sourced by the RUN circuit (seatbelt warning system, brake and oil cluster pilot lights )

On Rallye cluster is on ACC buss bar and as you mentioned, the Acc circuit.

The female prong on limiter is the output to the gauges. The input is an U shaped male terminal, sharing connection with the noise supressor condenser.

The rubber coated 90* male end is the wiring to the gauges. It should get some holding pressure when being plugged to the limiter female end. Not reallly a click, but a holding pressure.

 

[Dibbons]

The rubber coated 90* male end is the wiring to the gauges.

OK, then I forgot already what the loose wire looked like, it's definitely a female wire end. Maybe I can squeeze it with something.

Can't squeeze it closed to tighten it because it is a hard black plastic (rectangular-shaped) and the terminal is locked inside it.

I did hold the wire on with one hand and turned the ignition key to the "on" position with the other and took a peek at the fuel gauge. However, the fuel gauge remained on empty. I guess there could be a problem with the float/sensor inside the gasoline tank.

I removed the electric oil pressure sensor to install a mechanical gauge, so no testing can be performed there.

I suppose the next time I fire up the engine I can see if the coolant temp gauge will function. Might have to hold the wire onto to voltage limiter while checking that one. To be continued. I really need to know fuel level, don't want to ran out of gas and block traffic or worse.

 

[Nacho-RT74]

Well there is a female one too, for the condenser but if that one gets unplugged the gauges will still work. Not the other one thought. Hence why I’m focusing on the one to the gauges.

Check the pics at this auction.

1970 74 CUDA CHALLENGER STANDARD DASH VOLTAGE REGULATOR CAPACITOR GAUGE 2984767 | eBay

And

Disculpa la interrupción...

This one to, althought the female prong to feed the gauges pigtail got bent

Disculpa la interrupción...

 

[Dibbons]

I found this photo online which shows the hard plastic cover over the power wire to the voltage limiter (the connector to the left of those soft rubbery ones). No easy way to make it fit any tighter.

 

[Nacho-RT74]

Yes, a plastic one with regular female packard terminal goes to the U shaped male terminal shared to the condenser. That’s the powered one coming from fuse box.

There is a wider one which goes to the chassis/bracket ground prong. Very important, because without a good ground, gauges can burn since limiter will be inoperative and full 12 volts will be going throught. Althought still without that one some ground should be get throught cluster housing itself once cluster is firmly attached to the dash frame (and limiter is screwed in tight againts cluster housing)

Pretty sure the one loosen on pic with black wire is that ground

 

[Dibbons]

Update: I was able to remove the plastic cover from the voltage limiter wire and squeeze it closed a little bit. Now it seems to be tight enough to stay on. The coolant temperature gauge is now working but not sure about the fuel gauge. It does move a little bit but still below the "E" mark. It could be that the tank is almost empty and the gauge is working. Photo #1 key off and photo #2 key on.

And one will notice with key on (engine running) the converted ammeter gauge (now a voltmeter) shows a charge but with key off shows a discharge. I disconnected the battery ground cable and the voltmeter stayed in the discharge zone. Going to contact Redline Gauge Restoration to ask if that is normal after their conversion. To be continued ...

 

[Nacho-RT74]

The conversion is probably correctly done, just scale or gauge face is incorrect/unmatched. The scale on an ammeter gets the ZERO in the middle, then according with where the load comes or goes, will show charge or discharge. ( - or + )

On a voltmeter, the “ZERO” (well not allways a Zero but the smaller value on scale… tipically 8 volts) is on the left end and will sweep like any regular gauge. There is no minus or discharge reading on a voltmeter.

Gas gauge… you can ground the wire arriving to gas sender. It should full sweep to the full side

 

[Sinitro]

Well there is a female one too, for the condenser but if that one gets unplugged the gauges will still work. Not the other one thought. Hence why I’m focusing on the one to the gauges.

Check the pics at this auction.

1970 74 CUDA CHALLENGER STANDARD DASH VOLTAGE REGULATOR CAPACITOR GAUGE 2984767 | eBay

And

Disculpa la interrupción...

This one to, althought the female prong to feed the gauges pigtail got bent

Disculpa la interrupción...

Note the condenser located on the back of the dash cluster has nothing to do with the guage readings and/or action.
Its sole purpose was to remove any audible pop that could be audible through an AM radio when the voltage limiter makes/breaks its internal contacts.

Just my $0.02...

 

[Dibbons]

And one will notice with key on (engine running) the converted ammeter gauge (now a voltmeter) shows a charge but with key off shows a discharge. I disconnected the battery ground cable and the voltmeter stayed in the discharge zone. Going to contact Redline Gauge Restoration to ask if that is normal after their conversion.

I spoke with tech at Redline and, while on the phone, I could not duplicate the voltmeter being stuck on the far left of the scale with the key off.

He said it normally stays wherever it is when the key is turned "off". Then when the key is turned "on" it reads in the middle. Then with engine started and running, of course, it shows either higher or lower depending on state of charge of battery and what accessories are enabled. It was operating exactly that way when I was speaking on the phone with the tech.

 

[Nacho-RT74]

Note the condenser located on the back of the dash cluster has nothing to do with the guage readings and/or action.
Its sole purpose was to remove any audible pop that could be audible through an AM radio when the voltage limiter makes/breaks its internal contacts.

Just my $0.02...

I think already talked that on a previous reply? Dunno. But I know that. Never said it affects the gauge readings or function

 

[Nacho-RT74]

I spoke with tech at Redline and, while on the phone, I could not duplicate the voltmeter being stuck on the far left of the scale with the key off.

He said it normally stays wherever it is when the key is turned "off". Then when the key is turned "on" it reads in the middle. Then with engine started and running, of course, it shows either higher or lower depending on state of charge of battery and what accessories are enabled. It was operating exactly that way when I was speaking on the phone with the tech.

Not depending on the state of charge but the voltage on network. Being in between 13 and 14.5 volts it means alt is working. Being on 12 volts rate or less it means alt is not working or barelly working.

That doesn’t mean is CHARGING by what Charging literally means, but sourcing.