Connecting Voltmeter on Classy Gauges Cluster to Painless 28-Circuit Harness

[Jeff10]

Hi Everyone,

The problem that I am experiencing is the upgraded voltmeter on a Classy Gauges rebuilt cluster isn't working.

A local shop installed the new Painless 28-circuit harness. It general they did a great job.

At the present time the voltmeter is not registering at all. I'll be seeing what I can under the dash later today. (I took the easy way out and removed the seat on the driver's side.) The alternator is a one-wire type.

I have read several threads on CB (Paul had great advice) about connecting a voltmeter to a switched power wire and then grounding the other side of the meter. Just to make things easier, I thought I would call Painless and asked if they have any kind of best practice for which switched power wire to use. The person who answered the tech line told me to use the same wire as the ammeter. Based on everything that I have read, that didn't sound right. I didn't stay on the phone long.

At this point I know I am going to have to look at how (if at all) the meter is connected right now.

(Any suggestions on the least frustrating way to work on the voltmeter terminals. Is it possible to do it with the dash installed? If I remove the four screws securing the cluster to the dash do think it's possible to drop it out the bottom with all the wiring attached to it? Or.... remove the dash?)

Thanks,

Jeff

 

[DirtDonk]

Good morning Jeff!
Should be pretty straightforward, I think. You will have to see how it’s connected currently, of course, but hooking it to the ammeter wire isn’t the best practice, as you figured.
That wouldn’t mean the gauge is powered all the time. It would give an accurate reading, and a voltmeter doesn’t use much current, so it probably wouldn’t shorten the life of a charge if the vehicle sat for extended periods by much. But it’s still not the best practice.

The shortest route is to splice it into the input wire for the IVR. Probably a hassle though.
The easiest route is usually to connect it to the center stud on the back of the ignition switch.
That’s accessory power and is on with the key in the ON position or the ACC position.
Just like the factory did it.

 

[EPB72]

Did the meter ever work?? after wiring harness installed..,, or is the cluster being added after wiring arness?....have you checked the fuses? ,,, as far as access removing the drivers side fresh air duct gives you good access... have you contacted the shop that installed the harness, maybe they will work with you or have some insight?

 

[Wild horse 75]

There should be keyed 12v power already at the gauges. All you need is to add a wire from that power wire to the voltmeter terminal and give it a ground which you will also have on the cluster for the lights. Don’t need to be chasing wires all over. Keep it simple. A volt gauge requires so little amperage that it won’t affect the operation of any of the other gauges.

 

[Jeff10]

Hey Guys,

I'll let you know what I find once I get started.

EPB72, All of the other gauges work. The refurbished cluster and the Painless harness were installed at the same time. I have reached out the original shop; but, I haven't heard back from him. The ducts shouldn't be a problem.

Wild horse 75, I agree... simple is best.

Thanks for your input.

Jeff

 

[Wild horse 75]

The instructions for the painless harness are online. Have a look through them. there should be a wire marked gauge power use that and just share a terminal with one of the other gauges. Then if it needs a separate ground share it with the light ground.

 

[DirtDonk]

Can’t share it with another gauge (after the IVR).
Has to be before the IVR, or you’ll get a false reading on the volt-meter.

 

[Wild horse 75]

Any IVR will be internal to the gauge. The painless harness will have a switched 12V wire to feed the gauges. That’s the wire I’m saying he should be sharing for the volt gauge. Since painless has no idea what gauges you’re using they can only supply 12V straight. I’m not suggesting he tries to grab a sender side wire.

 

[DirtDonk]

I get that. But no matter what the harness, anyone using a factory gauge cluster is using an IVR.
And the OP said he’s using a Klassy Chassis rebuilt cluster. Which means he’s got a factory cluster.
Or at least that’s what I took it to mean when they used the phrase “classy rebuilt” originally.

 

[Jeff10]

Hey Everyone,

Well.... progress at a slow pace. Seat removed and steering wheel removed, and still hardly enough room to work around the 3 pedals and the roll bar. Ugh.

I did confirm the wiring last night and compared it to the Painless manual.

The positive terminal on the voltmeter on the reworked cluster is Black/Yellow and the ground side is black. The good news is the shop that installed the harness did a great job bundling all the wiring together. The bad news is that they did too good a job. It's going to be kind of a mess once I get done with this. Pretty disappointing. Based on what I can see both of these wires do a turn into the bundle that leads to the firewall.... so my guess is that they are going to the alternator.

I also confirmed that the positive feed shows +12V when the key switch is on. (The ground side shows open... no continuity.)

So... the voltmeter is wired in the same way as the ammeter would have been wired.

Planning next steps...

1. The voltmeter has not worked in the short time the build has been running. I'm trying to understand if the voltmeter was damaged.
2. Based on one of Paul's comments earlier, it sounds like being wired the way it is should work when the motor is running and charging. (It is not working now when the motor is running.)
3. If I remove the black/yellow and black wires from the voltmeter, do I need to splice them back together to complete the circuit for the 3G type alternator I'm running? (I have read where most people do this, although there are some that leave them disconnected and don't have a problem.)
4. Running new wiring to the voltmeter to match the original install work for the Painless harness is going to be really difficult with the dash installed. And, pulling the dash probably means removing the roll cage and steering column. I am leaning towards running the power wire from the ignition switch to the gauge and a separate ground from the voltmeter to a lug on the bottom of the dash that was used to ground the tachometer (I think). This simplifies things; but, it won't be the way it should be to match the other work. (And, at this point I am just hopeful that the meter still works. If the meter doesn't work, I will need to rethink whether or not it's worth everything to replace it.)

This build is pretty nice and I hate do anything to take away from it's value. I don't want to spend any more time or money fixing something that wasn't done right to start with, although I do want it to be something that won't be criticized by anyone who might buy the Bronco. It's kind of a fine line.

Any thoughts?

Jeff

 

[DirtDonk]

While you’re under there simply test the meter.
Since you have an open on the ground now, run a dedicated ground jumper, temporarily, from the ground post to a known ground.
Doesn’t matter where, but once you touch the ground, the gauge should read battery voltage.

Speaking of battery voltage, did you test the black with yellow wire with the key off?
Is this the large size (10 gauge) wire normally for the ammeter? If so, it should have power at all times.
And no, you do not use it typically with a 3G.

Verify under the hood that your 3G has a dedicated charge wire running directly from the main output post to the battery.

I don’t know if the Painless harness requires the two wires to be connected, but you can test that theory by leaving them disconnected and see what happens.
But at any time you’re working on these, make sure they don’t have 12 V with the key off. If so, you need to disconnect the battery when touching this wire. And when you are testing, leave them capped off. You can use wire nuts temporarily to protect the end. Quicker than electrical, tape and easy to remove.
I know that Centech does require that they be connected because, like the factory harness, if you disconnect the 2 halves of the ammeter wire, literally nothing on the truck works.
You have to keep them connected.
But not the two normally used on a voltmeter.

You would have to find the other half of that wire. In fact, just to clarify, are the two wires on the back of the volt meter the same large 10 gauge wire?
If so, they do not belong on the voltmeter.

If you can take a clear picture of the back of the gauge cluster, that would help.

 

[1buckeyefan1]

I just went through the same setup.. explorer swap, painless harness and rolled my own voltmeter. I had it working and now tore it all back apart bc my other 3 gauges quit working ( probably a short)

What I did was use one of the extra painless accessory wires ran over to the voltmeter+. You should have extra if you want to do that and then tap into a ground stud for the other side of the voltmeter.

Alternatively if you don't want to run another wire in your bundle, you can splice the positive into the IVR. That's already at the gauge cluster.

Take it all with a grain of salt, as I'm now tearing my gauge cluster back out.. so I could be wrong. But it sounds right

 

[wsager]

Is the painless harness the Bronco specific one?

 

[MarsChariot]

What 1buckeyefan1 did is what I did. I used one of the dedicated ignition-on accessory posts on the Painless fuse box and ran it directly to the voltmeter. Has worked fine with no problems.

 

[Oldtimer]

At volt meter:
Does black/yellow read 12volts:
1) Key off?
2) Key on?
3) Is black connected to ground?
If 2&3 are yes working volt meter should read battery voltage.

Volt meter is connected between battery+ and ground.
Amp meter is connected between battery+ and alternator output.

You need to find the other end of both wires to determine how harness is set up.

If harness is set up for volt meter, DO NOT connecte black/yellow to black wire together.
If you do you will find out if system is properly fused, or you will see smoke.

If harness is set up for amp meter, total accessory/charging current is passing from black/yellow wire, thru meter, and into black wire. If cluster has VOLT meter, and you pass this current thru it, it IS broken and needs replacing.

 

[DirtDonk]

Agreed. I believe the wire harness installer followed the instructions for an ammeter, with the voltmeter.
Pretty sure the volt meter is toast, because the two wires connected to it are not positive and negative. They are two ends of the positive charge wires.
With, as Oldtimer said, potentially lots of current passing through it.
Far more than a voltmeter can handle.

 

[Jeff10]

Hey Everyone,

I have confirmed that the voltmeter was wired like it was an ammeter. I haven't been able to confirm yet whether or not the voltmeter still works. I hope to do that today. (Worst case it will be this weekend.) I am not optimistic that it still works.... but, who knows? Everything you guys have said makes sense and makes it clear it's not likely to work. Pretty PO'd that the shop that installed the harness and cluster did it wrong and now is pretty much blowing me off because they are too busy.

The Painless harness is Bronco specific, 28-circuit.

If it comes down to the voltmeter being bad I'll have a decision to make about the direction to go.

I'll keep you posted. Thanks for all of your support.

Jeff

 

[Jeff10]

Hey Everyone,

Not sure how it's possible with the way the meter was wired....

But...

The voltmeter works. I was able to remove the two ammeter wires from the meter terminals and attach two jumpers. Checking the voltage of a 9-volt transistor battery it moved the needle slightly (below the 10V on the meter scale). I connected 2 9-volts in series and the needle pegged above the 18V on the meter (max scale) and dropped down to around 17.

I just need to wire it correctly now. Probably this weekend.

I've been discussing the two ammeter wires with Paul. Right now they are not connected. Some people with the Painless harness say it isn't necessary even though it says it is in their manual. I think the plan is to make sure it runs and charges with them disconnected. If there's a problem I'll connect them together. Any other experience will be appreciated.

Thanks for all the advice.

Jeff