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Mystic Knight
09-09-2007, 09:46 PM
Here's a little quiz concerning something I just noticed while wiring up my truck.

I have a '91 S15 Jimmy that's been heavily customized. I'm slowly getting things back together. As I've been wiring up the custom led lighting I've noticed something that left me scratching my head. Nothing really wrong. Just had me curious why it's doing this...

If I ground my multimeter to the body and put the + to the turn signal hot I get a constant 12v. Not alternating as expected.

If I ground my test light to the same ground and put the tip to the turn signal hot the test light blinks.

I then went one step farther and wired the test light up again then touched the multimeter to the test light leads. Then I could see the voltage alternating between 11 and 4v.

My question is this: What makes the test light blink when the multimeter reads a constant 12v? Does the multimeter carry no load? I've installed an "electronic no-load flasher" which I assumed would flash regardless of the load. Any ideas anyone? This is just a curiosity thing.

spinelli
09-09-2007, 09:51 PM
Sounds like there is a setting on your DMM to hold the peak voltage reading.

Mystic Knight
09-09-2007, 10:03 PM
I might agree if it weren't for the fact that it constantly changes when it's hooked up to the test light leads.

Mystic Knight
09-10-2007, 11:55 AM
Haha. Not too many people excited to answer the Blinker Quiz. I didn't think there's be too many people with a ton of knowledge about flasher modules. :p:

Ferendon
09-10-2007, 05:08 PM
DMMs don't give instant readings. The drop in voltage is quick enough that the DMM doesn't get a chance to read it before the voltage comes back up.

smd4life
09-10-2007, 05:12 PM
DMMs don't give instant readings. The drop in voltage is quick enough that the DMM doesn't get a chance to read it before the voltage comes back up.

x2

Relax
09-10-2007, 05:17 PM
He said it works with the test light hooked up- so its nothing wrong with the DMM or its refresh rate.

Mystic Knight
09-11-2007, 11:52 AM
Dur... The more I think about it the more I'm thinking the multimeter probably doesn't have much resistance. If it did you wouldn't be able to measure resistance with it accuratly. That is, unless it compensates for it's resistance when it displays the measured resistance in a circuit.

It's called an "electronic flasher". I've been told they're also called "no-load" flashers. I'm betting it's should really be labeled a "low-load" flasher. If it does need some kind of resistance to flash that would explain why it flashes with a bulb but not without one.

I've been looking for some info on the electronic flasher I bought but haven't been able to find much info. Gotta love products made in Korea. Over the next few days I'm going to try to get the other lights wired up now that I know the flasher actually works with a regular bulb. If I can't get it to flash correctly I'll throw a resistor inline to fix the problem. Seems kind of stupid having to do that though seeing as that's what I was trying to avoid when I bought the electronic flasher.

Like I said, this isn't really a problem with my ride. Just more curiousity than anything. It's stupid little distractions like this that make work on my ride go so slow. :laugh: