Bought 12v Gauges, need help!

Luke Wilson · August 12, 2014, 01:05:05 PM

We're still in the middle of redoing the dash, and the UPS man just arrived with 5 beautiful new digital gauges from Summit Racing. Only missing the air pressure gauge now, which will arrive tomorrow, had to get it from Dakota Digital because Summit doesn't make one.

As soon as I got the instructions out for the first one, I realized that I made a mistake: in the process of trying to the find the balance between good looking and (relatively) inexpensive gauges, I had forgotten that they needed to be 24v, not 12v. And of course, all the gauges I just bought require 12v.

So my question would be, what is the best/cheapest solution here.... I would like to use these gauges if possible, I really like the way they are going to look. I found this helpful to see different solutions, but don't know which one would be best for this application: http://bus.getdave.com/Docs/12Von24V/

Thanks for putting up with the newbie questions - see, it even says I'm a newbie to the left of this post!

Luke

bevans6 · August 12, 2014, 01:42:59 PM

Many, if not most, MC-9's have a 12V source in the main electrical bay under the driver's window, I think it's stud 57. I would check there. The amount of current a few gauges will use is probably irrelevant to issues of battery balance and such.

Brian

Lin · August 12, 2014, 02:03:05 PM

Did you buy new sensors to match the gauges?

Luke Wilson · August 12, 2014, 02:14:35 PM

Thanks for that info, Brian, appreciate it a lot. Will definitely check on that.

I didn't buy new sensors, Lin. The old ones all seemed to be working, just unmatched and ugly! I didn't think it would be necessary to replace senders.

Lin · August 12, 2014, 02:24:57 PM

Like-- senders have to match the gauges resistance range (except for voltmeter). I am also not sure if the 12v gauges are compatible with senders designed for 24v.

oldmansax · August 12, 2014, 02:28:50 PM

Quote from: Luke Wilson on August 12, 2014, 02:14:35 PM
I didn't buy new sensors, Lin. The old ones all seemed to be working, just unmatched and ugly! I didn't think it would be necessary to replace senders.

Sensors have to be matched to the gauges.

TOM

harleyman_1000 · August 12, 2014, 02:48:58 PM

Can you return or exchange the 12 volt gages for 24 volt ones?

HB of CJ · August 12, 2014, 03:59:03 PM

Answers already given and thank you. Yep...you need 24vdc gages to do it the best way. Yep....each gage must have an engine correct gage correct sender. Also important is the distance run from the gages from the engine and senders. Everything needs to be balanced. Are you going to run a big amp gage?

Another can of worms. Dedicated grounds also come to mind. Might be best to return what you have and start over. Sorry. This stuff needs to be researched and properly balanced so it will work right. HB of CJ (old coot) Welcome to this fine Bus Conversion Forum.

PS. Have you considered a fun trip to your local, friendly, knowledgeable, (not really) CHEAP heavy duty truck wrecking yard bringing your own hand tools and a plastic 6 gallon round bucket with handle? Find a wrecked tractor with your same mill and pull all the neat cheap cool trucker gages you want plus the needed proper senders?

You can easily get about a $1000 bucks worth of all the gages you need, some you do not, and some that are just heavy trucker cool for about 10 cents on the dollar. Yep!! Plus it is fun doing all of this, which is also the point.

RJ · August 12, 2014, 05:27:22 PM

Quote from: HB of CJ on August 12, 2014, 03:59:03 PM
PS. Have you considered a fun trip to your local, friendly, knowledgeable, (not really) CHEAP heavy duty truck wrecking yard bringing your own hand tools and a plastic 6 gallon round bucket with handle? Find a wrecked tractor with your same mill and pull all the neat cheap cool trucker gages you want plus the needed proper senders?

You can easily get about a $1000 bucks worth of all the gages you need, some you do not, and some that are just heavy trucker cool for about 10 cents on the dollar. Yep!! Plus it is fun doing all of this, which is also the point.

HB -

Great idea, except. . .

Most 18-wheelers are still 12V, so he's right back to square one. $:-\$

FWIW & HTH. . .

eagle19952 · August 12, 2014, 05:41:39 PM

so your saying that all of your current gauges were toast...?

Luke Wilson · August 13, 2014, 04:44:19 AM

Okay, looks like I'll be returning my gauges then... a real bummer, but a lesson learned.

Just so I'm clear for the future, are senders always specific to gauges then? Meaning, if I were to get 24v gauges (new or from a truck junkyard), will they work with the original senders or are they something that has to be replaced together?

Thanks for all the help!

Luke

bevans6 · August 13, 2014, 09:36:54 AM

I have never bought a gauge that didn't come with it's matched sender right there in the box Sometimes with a complete wiring harness with all the special plugs to make it all work. FWIW.

Brian

Lin · August 13, 2014, 02:49:13 PM

You can buy gauges and senders together or separately. If you are getting new sending units, make sure they are the right port size. You should be able to research the ohm range on your existing gauges and buy new gauges with the same range if you want to do it that way. I doubt that the original units were anything so exotic that you would not be able to match them easily. If they are the original gauges, MCI will be able to tell you the range. If not, whatever the manufacturer is would be able to do the same.