The Stovebolt Site Forums The Shop Area The Electrical Bay Gauges ?

Don't know if this is the correct forum or not? (hipo). Anyway i have a 51 Chevy truck with an ls-1. I have aftermarket Classic instrument gauges. The wiring harness I purchased separately, has the instrument wires available. I want to know how can I check the signals from these wires.

what does 'check the signals' mean? you want to find out which wire is which? you want to find out if the senders work? you need to clarify what you're trying to do

an ohmmeter will track the connections, although I'd expect the harness to have some sort of labels .... to find out what's happening on each wire, you'll have to start by knowing what's supposed to happen, electric gauges mostly have variable resistance senders so you'll need the engine running to check their function

Bill

I know what wires are what. I want to know how do I check the wires from the harness to see if the input is getting to the gauges. Running the engine is not a problem.

Check the input with a voltmeter. Check the senders with an ohmmeter.

What type of reading should I be looking for on each meter ?

You are making this a lot more difficult than it needs to be. There should be a 12V power source to each gauge. As stated above the senders are variable resisters to ground. The fuel sender for instance will be approximately 0 to 30 ohms. Approximately because truck gauges are not scientific instruments. They are a reference. I don't know what the ohm range is on the oil and temp sensors but they vary with the oil pressure and the coolant temp. If you get some resistance then they probably work.

As stated above, there is really no reason to go through all this. Hook them up and see if they work. If they don't, then troubleshoot.

The reason that it is difficult is because the answer to the questions are being avioded. if you don't know just state that.The gauges has been hooked up and they are not working !!! why else would I be checking the wiring?Seems rather elementry to me. I simply asked what type of reading I should be getting. I'm no electrician. and as you can see from the answers no one addressed this till now. I don't need to know to run the engine, to hook them up and see what happens? I simply want to knpow what ype of reading I should be getting. I may have asked it in the wrong way. But I can hook the tester up and find out if I'm getting the correct signal if any at all is what I was asking. If the subject is too difficult just dont answer.

well, if you want folks to help figure out your problem, it helps to clarify the situation, and helps if you understand the reading you'll get anywhere will depend on the gauge - so you're just getting this all assembled, it's running and completely wired up per the appropriate wiring diagrams, and none of the gauges do anything?

the senders don't have "signals", they're pretty much resistors that affect the current flow thru the gauge, the "signal" is battery voltage to the power terminal of each gauge, the amount of power that the resistance allows to flow causes the gauge to read

I'd first off check the wires with an ohmmeter and insure things are connected to the right locations - next would be insure the gauges have power supplied to the proper terminal .... I'd expect to get a paper with the gauges that has wiring shown, and once wired properly, I'd expect the gauges to "twitch" somehow as soon as the key is turned, if not, they aren't getting power .... have a fuse panel?

Bill

You won't be getting any more advice from me. It was explained by Bill in basic terms and you didn't get it. I explained it in simpler basic terms and you lashed out at me for it. Good luck with your project and your attitude.

When you calm down go back and read nd find out who lashed out. If i did not get it do you think your statement was going to make me understand better? You explained absolutley nothing.Yuo answereing are not will not make or break my project. try and be more considerate when you ask questions. " Just hook them up and see what happens" Wow how genious is that

Gauges are hooked uyp and has power, and are grounded. The fuel gauege is the only one that reads, the lights are also working in the gauge. They zero out when the power is off. The oil pressure gauge is not moving at all when fired up, but the computer is satisfied?? truck will run and drive just not sure if the readings are correct. that's why I was wondering if there was some type if signal I could check for?? I thought that was a simple enough question.I will call the harness maker and see if there is something I'm missing or he can help me with.Wiring has been rechecked grounds,hot,lights, etc... all seems to be in order.Fuses are good , gauges seem to be ok?

hmmm, so it'd appear the senders aren't correct or you've used teflon or other sealer on the sender threads, isolating them from the required ground - if you ground the oil pressure sender connection, the gauge should read above 100psi .... not sure about the computer hookup, but the gauges should have their own senders, are the senders from ,or recommended by, Classic Instruments? are you using the Classic Instruments wiring harness?

as said, the senders are simple variable resistors, they don't generate signals, they respond with resistance changes to temperature or pressure changes

Bill

No sir i have not removed or installed any senders, I simply installed the harness (engine stand alone) the harness for the chasis is american auto wire, the classic instruments are connected through the american autowire harness the dash wires for the engine has the marked wires: oil pressure, water temp,and speedo.

I would try a couple of jumper wires from the senders to the gauges. At least then you would isolate any wiring problem. Just be sure to disconnect the current wires first. I'd do one guage at a time and have the engine warmed up for the temp