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Chasing a short? (87 4runner front turn signal)

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Old 05-31-2012, 11:59 AM
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Chasing a short? (87 4runner front turn signal)

Soooooo....after finishing up my transmission swap (part 2), it wasn't long that I got back on the road and my driver's front turn signal stopped working.

In the cab, I heard a faster "click click click" when the left turn signal was engaged. I got out of the truck and the rear was working, but the front was not. I went to the store and got some new 194 bulbs, replaced the dead one (yes, it was burnt out), and buttoned it all back up. Same thing going on (though the new bulb is not dead yet).

I've tried a couple different 194s that I know are not dead - none of them work.

All the other blinkers work fine - are they all on the same circuit?

I'm a noob with electronics, but have a multimeter and even one of those light tools with the ice pick style end to pierce wires. I came across a site that had this diagram, showing how to do a test to find a short with the batter disconnected:

http://www.mustangmonthly.com/howto/...t/viewall.html

http://www.mustangmonthly.com/howto/.../photo_04.html

Is this the path you guys would take to find a short? Does this scenario sound like a short (the positive wire in the harness is somehow bare metal against the bod panels/frame, or the negative return wire?)?

Any tips much appreciated!

Phil
Old 05-31-2012, 02:09 PM
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Wink

Is it a short? If so then your fuse will be blown.

If it is a case of the blub not working look at the light socket have you cleaned it with electrical cleaner??

If only one is not working I bet the socket is corroded if it is beyond fixing time for a new one.
Old 05-31-2012, 02:16 PM
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Originally Posted by wyoming9
Is it a short? If so then your fuse will be blown.

If it is a case of the blub not working look at the light socket have you cleaned it with electrical cleaner??

If only one is not working I bet the socket is corroded if it is beyond fixing time for a new one.

I honestly don't know yet - have not dug into it but wanted to make sure I had the right approach. My assumption is that all the turn signals (at least the two front ones) are on the same circuit/fuse, so the fuse would not be blown...and I haven't checked yet.

I'll check the connector for corrosion as well.

If it's a short in the wires to the socket, is the approach above the best way?
Old 05-31-2012, 05:13 PM
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Turn on your drivers signal, connect the negative clip of your test light to the neg post of your battery. With the bulb removed from the socket use the test light and probe both connectors in the socket. Because your test light is grounded if there is power to the socket when you probe the positive side your test light should flash with the flasher. If it doesn't there is a problem with the positive feed. If it flashes then the problem is in your negative or ground return. Could be corrosion as already stated or a broken wire.
Old 06-01-2012, 08:05 AM
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Originally Posted by Hadmatt54
Turn on your drivers signal, connect the negative clip of your test light to the neg post of your battery. With the bulb removed from the socket use the test light and probe both connectors in the socket. Because your test light is grounded if there is power to the socket when you probe the positive side your test light should flash with the flasher. If it doesn't there is a problem with the positive feed. If it flashes then the problem is in your negative or ground return. Could be corrosion as already stated or a broken wire.
Thanks Hadmatt. So, with this setup, if everything were working the way it SHOULD, I would only see the test light flash when connected to ONE of the two socket terminals, correct? (the positive side). There shouldn't be flashing when connected to the negative side, since theoretically, the test light would be 100% connected to ground and not have any + input, right?
Old 06-01-2012, 03:02 PM
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You got it!
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