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Author Topic: Anyone know about electricity and voltages and stuff?  (Read 347 times)Share

AVR2

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Anyone know about electricity and voltages and stuff?
« on: January 14, 2012, 02:50:54 PM »
Hi chaps,

The digital information display in my ancient Jeep is dead and I'm trying to work out if it's the unit itself or if it's just not getting power. Got the pinout from the service manual, and connected my multimeter to the 12V and ground wires on the plug, but I'm not seeing either a steady 12V or 0V. Instead, I'm getting crazy random readings that are constantly changing, mostly in the minus range, and anything up to 400V (or -400V). Anyone have any ideas what's going on there?  :dunno:

The multimeter seems to be working OK because when I connect it across the battery terminals I get a steady 12.5V.
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Ian

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Re: Anyone know about electricity and voltages and stuff?
« Reply #1 on: January 14, 2012, 04:17:49 PM »
After seeing Richard Bailey in actio over the past few days I suggest contacting RBailey on the forum.
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Desert Dawg

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Re: Anyone know about electricity and voltages and stuff?
« Reply #2 on: January 16, 2012, 08:54:57 AM »
You possibly have a 'dry joint' somewhere in the wiring loom that supplies 12v to the display unit.

Working backwards from the display unit, locate and check all connectors etc... It may be as simple as unplugging the connectors, cleaning and spraying with contact cleaner and re-inserting the plugs/connectors in the loom. Also check the fuse connection in the main and/or sub fuse boxes as well.
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rbailey

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Re: Anyone know about electricity and voltages and stuff?
« Reply #3 on: January 16, 2012, 12:05:35 PM »
Yeap, sounds like a dry / dodgy joint.
Out with the cleaner and some scotch cloth, clean and wiggle.

Also are you sure it is 400 V and not 400mV on an auto ranging meter ?

If you are SURE that you have the right pin and it should be 12v then try a direct power feed off the battery and see if that helps.
However if it is not 12v and a mV or mA signal and you supply 12v you will make a lot of blue smoke and that is expensive.
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dwr

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Re: Anyone know about electricity and voltages and stuff?
« Reply #4 on: January 20, 2012, 09:35:37 PM »
Dry joint/bad connector (probably).  LCD style meters do stuff like that if they themselves have a bad connection or sometimes when their batteries are dying, if they aren't a 'pro' name like Fluke etc...

kr  D.
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AVR2

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Re: Anyone know about electricity and voltages and stuff?
« Reply #5 on: January 30, 2012, 03:15:20 PM »
Thanks guys. Haven't been around for a while but will check it out later.
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