Need help using a 12v test light

Question

This should not be this complicated. I don't understand what I am doing wrong.

I am trying to test if there is voltage to a switch.

I hook up my test light negative and positive to an old 12v battery I have sitting around. It lights up.

I then keep the connection to the 12volt negative and put the tip of the test light on the power wire of a switch I am NOT sure is getting power (3 way rocker switch for hydraulic slide outs). Nothing.

I put the tip of the test light on a switch I know HAS power and is working (the center connector of a 3 way rocker switch for the electric slide out). Nothing.

12 volt is on in the trailer. The electric slide works.

Why?

old-biscuit · Answer

"I hook up my test light negative and positive to an old 12v battery I have sitting around. It lights up.

I then keep the connection to the 12volt negative ......"

If you are leaving the negative connected to the old battery nothing is what should happen. The old battery sitting around is not part of the circuit.

Need to put negative lead on a good clean ground that is part of rig....frame, ground stud etc.

Test light is OK for testing if power is available BUT it will NOT tell you if enough power is available.
A digital volt meter is a better tool

yc_1 · Answer

Put the alligator clip on your battery positive and repeat the test. The switch may be set up to supply a ground versus voltage.

dennis_m_m · Answer

Maybe I'm reading too much into this, if so I apologize.

You said: "I hook up my test light negative and positive to an old 12v battery I have sitting around. It lights up.

I then keep the connection to the 12volt negative and put the tip of the test light on the power wire of a switch"

I read that to say that you are leaving the ground (negative) connection on the test light connected to the old battery. Is that right? If so you will not get a light. The ground needs to be on the same 12 volt circuit as the switch.

winged_one · Answer

Ok, finally was able to get a decent ground on the trailer and found electric to the electric slide, but nothing to the hydraulic slide swich. Was able to open and close the hydraulic with the remote, so I don't know.

Guess it's time to see if our extended warranty is worth what we paid for it.

wa8yxm · Answer

Are you sure the switch is switching POWER to the slide controller?It might be grounding the desired direction of travel

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Need help using a 12v test light

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