Help wiring a new voltmeter. Can I use the wires from the cigarette lighter / powerpoint harness?

I've been following this site for a long time now, but have finally created an account so I can start posting stuff!

I am starting to work on some mods with my 2013 Tacoma. Most of them will be external LED light panels and some switches on the interior to toggle them. Since I'll be doing a lot of electrical work, I am starting with a simple voltmeter. If you're curious, here is the specific product I purchased from Amazon (and received yesterday):

$16 WATERWICH DC12-24V/0.1-10A Dual LED Digital Multimeter Amp Voltage Meter 2-in-1 Current Tester and Voltage Tester for Boat Marine Vehicle Truck ATV Car Camper LED Round Panel (Blue)

Voltmeter

As you can see from the pic, it's a pretty good fit for one of the cigarette lighter / power point spots in the center dash area. Incidentally, I'm going to replace the other one with a dual USB charger.

I've managed to remove the cig lighter / power point easy enough. I am wondering if I can use some of the wires from the cig harness to power up the voltmeter. It would seem that there must be simple power and ground wires from the harness and it's my understanding that so long as a power wire is hooked up to the voltmeter that's on the same circuit as the battery then it should get a proper reading. I've included a pic of what my particular center dash console looks like, though I assume it's pretty similar in most models.

Unfortunately I'm extremely new to all of this and so I'm trying to be cautious, but at the same time am pretty comfortable with the general wiring and such. If anyone is able to provide me with just a little bit of help on this part, perhaps a little confidence that I can in fact do it this way, and even a little guidance with their own suggestions, I would greatly appreciate it!

Thanks so much in advance.

 

Simple answer is yes.

Here is a print: https://www.customtacos.com/tech.ol...toyewd/06toypdf/ewd/2006/tacoma/h/em01d39.pdf

Green is power, White with a black stripe is ground.

 

Wow. That was such a fast reply. Thanks so much for that! I will probably give that a shot tomorrow.

The voltmeter I purchased has an readout for amperage too and so it has a third prong on the back of it. I'm guessing that in order to get the amps to read I'd have to run that as a jumper to some other device that I have in the car? But I figured for the time being that I'd just use it to get the voltage reading and can update it in the future once I have something that I want to measure the amperage of.

Anyway, thanks for the quick response!

 

I would recommend getting yourself a cheap voltmeter from harbor freight they work very well for there price point sometimes you can get them free with a purchase. This way when do your next electrical mod you can get more comfortable testing wires. And having a continuity tester is handy to. Make sure you post your lights when done. Good luck

 

You have switch blanks so you could also just pop in a usb power port w/12v meter using the socket wires for power. Mictuning makes them. I cut out the entire section and made a new panel with 3 more switch slots instead of the two power ports. One of the ports feeds the usb/meter.

After that I made another panel to fit the lower cubby.

 

Thanks so much. I actually have a pretty good multimeter that I've been using for years. I'm fairly competent with wiring in general, but I just don't have a lot of experience with the vehicle wiring so I'm definitely excited to find people who not only have the knowledge to help, but who are generally excited about seeing people work on these projects.

Anyway, I will definitely post pics of the lights once I start moving forward with them.

 

So I'm definitely going to be using the switch blanks for some of the switches. But I have to ask, how did you make that bottom cubby thing? I mean, I have the cubby area down there and I don't really use it for anything. I'd MUCH rather use the space for a police scanner that I have and would like to reinstall. You did such a great job with that! Did you 3D print it or did you get it made some how?

If you happen to have the plans for it and wouldn't mind sharing, I'd really love to do something very similar to that!

 

I found a combo USB voltmeter on eBay, it goes right into one of the blank switch covers.

 

Is this so that you can watch the volts on your battery so you know when you should start the truck?

 

Nah it’s usally for people (like myself) who are running a lot of aftermarket electrical stuff such as lights, fridges, or audio stuff. It lets you know if you are drawing too much power from your battery somewhere. Most people just run them because they look cool.

 

Do you have an installation guide for this device. I would love to see it... Or a link to a web site.

 

So unfortunately I have to take apart that entire center console (as described in detail in a different thread on here) to mount it properly - which will be an enormous PITA, but I hooked it up to the powerpoint leads and it looks great

Thanks for the help with that!

 

One other quick question about it though, so it has a third prong on the back for connecting to the load -- presumably what gets the amperage reading.

So say I had another device immediately next to it with just a positive and negative connection. Do I look the negative prong to the ground and then join the power wire to the LOAD on the voltmeter so that it gets the amperage?

So the new device would have ground going to ground wire. And then power going to a wire that connects to the voltmeter load, and then that wire connects to the original power wire for the new device? Basically a daisy chain of the power that goes through to load? ...or am I supposed to use the ground connection for the amperage load? ...or does it not matter?

 

Basically something like this? (apologies for non-standard electrical symbols)

 

For the ammeter to work you would connect the meter inline with the load, between it and ground. The 3rd pin is one connection and ground is the other for the ammeter. That way the device current goes to ground through the meter instead of a different ground connection.

 

Unfortunately, I do not. The device just came in a small plastic bag with 3 wire clips and that was it. No wiring diagram, no nothing. The back of it along side each prong just reads "+", "LOAD", and "-". So I just had to go off of that. There were some people complaining online that it had no wiring diagram with it, but people also said it was easy to figure out (which I suppose it was, but I wanted to be extra sure since I'm not skilled at wiring trucks)

 

Eliminate the wire from device + to meter load. Device + to 12v+, device - to meter load, meter - to ground.

 

Ahh. Awesome. So basically the same thing, but use the ground instead of the power or no additional jump to ground at all? Basically just the voltmeter itself creates the ground for the DEVICE.

Here's two possible pics of that wiring:

 

In other words the amp meter only reads the single specific load to which it is attached. That was what I wanted to see.To get the total load you would need to be on the Main Cable from the battery to see total current draw on the system. I'm just not seeing the usefulness of the Amp Meter.

 

So yea, I was originally hoping that I could set it up somehow so that I could get the total draw on the system, but I'm not really sure how I would go about doing that. I'm afraid I don't understand the vehicle wiring enough to really make a guess on how I'd have to wire that.

In terms of the usefulness, I'm planning to install a bunch of lights on the exterior of the truck so it would be nice to see what they're drawing, but I tend to agree that seeing an overall load when I turn things on/off would be much more useful and interesting.