indicator insanity

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Trying to rewire '73 850, and the indicators are driving me insane. both front indicator work as they should, but the rear dont. There is continuity between front and back on each side, the flasher clicks, but the back refuse to light...
When I plug in the indicator idiot light, the front one either side flashes brightly, and all the other 3 flash very weakly. Now they are doing it with or withour idiot light...
 
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They do not have a dedicated earth wire, instead they earth through the chromed plastic surround and then the chrome stem. I got fed up with all the issues and added dedicated earth wires (ok battery return wires) to all my indicators. You have to dismantle them, feed the red wire through the hole in the middle of the chrome stem and the add a ring connector to fit one of the 2 screws holding the bulb holder. The other end of the red wire needs to go to the nearest red wire in the harness. The rear ones give more issues than the front ones, the rear tail light may also depend on the mudguard for its battery return as I am sure I added one at the same time, but memory is hazy on that one..
 

maylar

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LED's or light bulbs?

Check the ground on the rears. I think it comes from the frame.
 
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They do not have a dedicated earth wire, instead they earth through the chromed plastic surround and then the chrome stem. I got fed up with all the issues and added dedicated earth wires (ok battery return wires) to all my indicators. You have to dismantle them, feed the red wire through the hole in the middle of the chrome stem and the add a ring connector to fit one of the 2 screws holding the bulb holder. The other end of the red wire needs to go to the nearest red wire in the harness. The rear ones give more issues than the front ones, the rear tail light may also depend on the mudguard for its battery return as I am sure I added one at the same time, but memory is hazy on that one..
checked all the earths, all good...
 
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How have you checked them, my multimeter said there was continuity but the amperage it was capable of carrying was not enough for the bulb to fully light of the old style indicator relay to heat its internal metal strip enough to flash.
I only check continuity... will install better earth and try
 
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How have you checked them, my multimeter said there was continuity but the amperage it was capable of carrying was not enough for the bulb to fully light of the old style indicator relay to heat its internal metal strip enough to flash.
You sir, have my gratitude.
Funny thing, connected an earth to 1 indicator, and both work! Thanks and Cheers!
 
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LAB and I (in the past) had found the rear TAIL light has a red ground wire for the tail/brake lite assy. The 68-72 style properly uses the red wire if turn signals are used.
The late square tail light uses the red ground but not the turn signals. These 2 red wires should be manufactured and installed so the rear fender and frame are not improperly relied upon to run your blinkies .
At least that is what I did to my MKIII. It was so long ago I had forgotten , but a quick look saw some neat wire fabrication I had done in 1995.
I probably should add, my added red wires were just ring lugs under the stalk mounting nuts. So my chrome must have been OK as I didn't run additional internal grounds.
Just a bigger junction block for all the red wire in the tail light area.
 
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Funny thing, connected an earth to 1 indicator, and both work!
Bet you did a rear and the matching front chimed in, the rear is always worse and once fixed the front and rear amperage/voltage got the flasher unit working. Your next task is to do digital on the flasher unit so the voltage does not vary the flash rate with the engine revs.

I use this one, the spare terminal for an extra warning light I run to a 12v siren muffled with foam and under the seat. I get to feel and hear the flashers regardless of speed.

 

L.A.B.

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Funny thing, connected an earth to 1 indicator, and both work!

Because the rear indicators are attached to the same metal bracket so an earth wire works for both.
Sounds like there's no frame earth connection which would normally be either a spade connector attached to the rectifier '+stud' tab or a ring terminal under the rectifier nut which is the frame connection to earth/ground as earth/ground is harness red, not the 'frame'.
 
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When you've sorted your earth/ground issues I would consider swapping out the relay for a more modern solid state one, this one gives you the option of putting in LED bulbs or even a mixture of traditional incandescent bulbs and LEDs on the same circuit.
 
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It gets worse...I made separate earth wires and ran them from both rear indicator internal globe mountings through the stalks and connected to the red earth bullet in the tail light. when I turn the indicators on, the (new) flasher clicks furiously and the indicators flash randomly... same both sides..
 

Derek Wilson

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It gets worse...I made separate earth wires and ran them from both rear indicator internal globe mountings through the stalks and connected to the red earth bullet in the tail light. when I turn the indicators on, the (new) flasher clicks furiously and the indicators flash randomly... same both sides..
Sounds like one does not have a good ground - does it do the same thing when you switch to the signal the opposite direction?
 
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