installing aftermarket voltmeter

-
Neal Zimmerman

Neal Zimmerman

Well-Known Member
Joined
Jul 24, 2016
Messages
154
Reaction score
53
Location
Springfield Oregon
My dash is no longer stock. I have installed all new Stewart Warners but the voltmeter is confusing me. I thought I could just slip it in to the stock wiring harness between the fat red and the fat black that used to feed the factory ammeter, but I am not too sure now. Instructions say negative post of voltmeter needs grounded.. Is that right??? And if so what is the color setup? Red goes to which post? Black to?? I'm confused.
Thanks
Neal
 
Neal Zimmerman said:
My dash is no longer stock. I have installed all new Stewart Warners but the voltmeter is confusing me. I thought I could just slip it in to the stock wiring harness between the fat red and the fat black that used to feed the factory ammeter, but I am not too sure now. Instructions say negative post of voltmeter needs grounded.. Is that right??? And if so what is the color setup? Red goes to which post? Black to?? I'm confused.
Thanks
Neal
Click to expand...




Then run the negative on the back of the voltmeter to the ground...

connect the two leads that used to be on the ammeter together in series and insulate them well from grounding...

I would then follow that into the fuse block input side and tap into that for the positive side of the volt meter... (You want right off the battery + or the big wire coming off the back of the alternator for the + input of the volt meter...

To run the gauge lights, tap into the orange wire coming out of the fuse block, or use the orange connector from the factory radio harness if you are not using that for the radio...
 
You cant connect a volt gauge to those red and black alt gauge wires.( That black wire is not a ground wire. It's simply on the side of the current path that eventually reaches grounds ). The volt gauge would be hot at all times and kill your battery. Attach those red and black wires together. Crimp a heavy gauge insulated butt connector, or solder and heat shrink, other. All the current in the cab goes through this so no such thing as overkill here. You can't bond these together too well. Find a blue with white tracer, that's switched hot. Tap that to positive side of the volt gauge. Negative side of volt gauge goes to chassis ground.
 
Last edited:
Here's what I'm running into.
I put a Bosch analog volt meter here and it twitched.
In the fused part close to the voltage limiter.
I'm running the RTE IVR4 limiter.
So I'm wondering , depending on what is used, the location may be necessary to avoid issues.

voltmeter.JPG



voltmeter 2.JPG












I tried it under the hood in this part of the circuit and it was stable.
So, I hooked it up further away and it was good.

volt.JPG
 
Neal,

I replaced the stock indash mopar ammeter with a Bosch voltmeter. I ran the ground terminal to the dash frame, drill a hole, scrape off the coating primer, use a terminal lug. Run the positive to any switched 12v source. Badda Boom Badda Bing.

FYI,

Marion
 
With our 40+year old vehicles, there are large voltage drops everywhere. Old connectors, long under sized wires are some of the main culprits. Make sure the dash is grounded well. Add extra grounding straps as needed to clean, unpainted, metal surfaces. The dash uses bolts and one black wire (at least on my ride) to ground itself. Your new volt gauge will give readings only as good as the connections that feed it.
 
The whole deal with the MAD article is getting the high charging current "out of' the two bulkhead terminals, and when you do that, the two then IN PARALLEL become a feed for the loads IN the car. So this is a "twofer" improvement

Crackedback sells a simple jumper that works. One thing you want to be careful of...........is bypassing this stuff.........you can end up bypassing the fuse link, and have NO protection for some old wiring.

The other issue related to the bulkhead/ MAD thing is the voltage drop in the harness feeding the VR, which then causes overvoltage.
 
Here's how that works, assuming the VR is actually "correctly" working and the battery is good.

1....It might be a ground problem, but fairly rare, although the VR (and the Mopar ECU ignition) MUST be grounded to the negative battery and AT THAT VOLTAGE, IE........no drop there

2....The BIG problem with these girls........taking the OEM circuit.......is drop in various points "on the road" to the VR

The functional path is BATTERY..........STARTER RELAY STUD.......FUSE LINK........through the BULKHEAD CONNECTOR (RED)........to the AMMETER.......THROUGH the AMMETER........out on BLACK..........branch off the WELDED SPICE........to the IGNITION SWITCH CONNECTOR..........through the SWITCH........out the SWITCH CONNECTOR ........(dark blue ignition "run") back out through the BULKHEAD CONNECTOR.........branch off to the ignition, choke if used, etc AND THE VOLTAGE REGULATOR

EACH of these points can have a bad connection, including the interior contacts of the switch itself.

One way to "cure" it is to cut the dark blue ignition out of the firewall, use the firewall side to trigger a relay, and the load contacts of the relay to feed the other end of the blue. Pull power from, say, the starter relay stud

You can measure VR power (ign) with key on/ engine off and compare to battery voltage. More than say .3V (3/10 of 1 volt) starts to ADD to battery charging voltage
 
adriver said:
Here's what I'm running into.
I put a Bosch analog volt meter here and it twitched.
In the fused part close to the voltage limiter.
I'm running the RTE IVR4 limiter.
So I'm wondering , depending on what is used, the location may be necessary to avoid issues.
Click to expand...
My volt gauge didn't twitch initially. Then a few days later that needle started continuous twitching. Knowing a twitch comes from a switch ( just like headlights and turn signals effected the ALT gauge ), with every other switch ruled out, no further diagnosis. A new voltage regulator fixed it.
I don't have any experience with RTE limiter in a vehicle.
 
You must log in or register to reply here.
-

Back
Top