Turn signal works; doesn't work

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m37jarhead
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Turn signal works; doesn't work

Post by m37jarhead »

Putting the finishing touches on hooking up the new front and rear wiring harness from Vintage Wiring.

Left turn signal only works intermittedly. Checked bulbs, connections and grounds. Jiggling the
turn signal lever has mixed results. Works sometimes; sometimes not.
Headlights, service lights, four-ways all work.

Any thoughts on where to check further?

Jerry
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Re: Turn signal works; doesn't work

Post by tbone1004 »

sounds like a bad switch from the lever. try bypassing the turn signal switch. If it works fine, then you have a bad switch. If it doesn't, use a test light and try that coming off of the switch and see if that works. If so, then you need to start chasing grounds.
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Re: Turn signal works; doesn't work

Post by Carter »

Disassemble the switch, unscrew 4 screws, halves might be stuck together so use a thin blade knife to coax them apart, nothing will jump out and get lost . Inspect and clean the contacts as you would with ignition points, remove oil film, oxides and possible corrosion on the points at the end of the fingers. You might want to clean the insides if the aluminum case as well since you have it apart, then reassemble and give it a try. I have done this with several and always had good luck bringing them back to life.

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Re: Turn signal works; doesn't work

Post by k8icu »

If you have a wire diagram you can take the connector off of the switch and jumper the wires for each light and see if the lights flash proper. If they do it's the switch that has issues. If not then it is either wiring or the flasher unit. Which flasher do you have the solid state or the older breaker type? That may be the problem also if you have the older system. And double check those grounds and make sure they are good that the lights and from the lights to frame etc.
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Re: Turn signal works; doesn't work

Post by m37jarhead »

Carter, great pic's. Points me right to the possible problem.

tbone and k8icu, more good ways to diagnose. Flasher is solid state and new.
Will recheck grounds too.

Thanks and will post results Sunday.

Jerry
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Re: Turn signal works; doesn't work

Post by tbone1004 »

bypassing switch should be pretty easy since all you have to do is take any hot 12v wire and touch it to where the left turn wire is. should start flashing normally and then you can at least determine that it is something in the switch then start taking it apart. good luck
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Re: Turn signal works; doesn't work

Post by m37jarhead »

tbone1004 wrote:bypassing switch should be pretty easy since all you have to do is take any hot 12v wire and touch it to where the left turn wire is. should start flashing normally and then you can at least determine that it is something in the switch then start taking it apart. good luck
Did you mean 24V?

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Re: Turn signal works; doesn't work

Post by tbone1004 »

sorry, yeah if it's still stock 24V then any hot wire coming jump will work.
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Re: Turn signal works; doesn't work

Post by Carter »

m37jarhead wrote:Carter, great pic's. Points me right to the possible problem Jerry
Glad to help Jerry, the switch is so easy to disassemble that it only took a couple of minutes to set up and get the shots. Hope you are able to correct the problem.
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Re: Turn signal works; doesn't work

Post by m37jarhead »

EUREKA !!

This morning I did exactly what Carter recommended. Cleaned up the points, re-assembled and
now all turn signals work. As Carter said.... probably didn't take me 20 minutes for what
turned out to be a minor project. Note that the points contacts did not "look" corrorded and
they seemed slightly out of alignment. Mom's nail file did the trick on the points contacts
and I did some minor adjustment to re-align to contacts.

For the little amount of time spent it might be worth anyone's while to do this maintainence
check on the turn signal indicator.

Thanks to Carter and all who contributed. Saved me some gray hairs.

Jerry
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‘43 GPW, '53 M37 W/W, ‘54 M170 Field Ambulance,
59 M43, '76 M151A2, '86 CUCV,
'43 GPW, 416 & 101 trailers.
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Re: Turn signal works; doesn't work

Post by Carter »

I am happy I was able to help solving you problem, I had the very same trouble with a NOS unit I installed on my truck and spent hours searching for a cause. I thought since the unit was new it must not be bad but after much time spent eliminating other possible areas of concern I focused my attention on the controller which, although was unused, turned out to be defective and with a thorough cleaning had a functioning turn signal system at last. After reading your orig. post I thought you may benefit from the knowledge I had gained through hours of trial and error. :D
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Re: Turn signal works; doesn't work

Post by j mccormick »

Mechanic to assistant- is the turn signal working? Assistant- yes,no,yes,no,yes,no.... :)
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Re: Turn signal works; doesn't work

Post by Carter »

LOL... :D
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Re: Turn signal works; doesn't work

Post by m37jarhead »

Yeah, thanks Carter. Saved me and probably many others untolled hours hunting down the problem.

Just goes to show, we can all benefit from other's experiences. Saves time, money and headaches.

I didn't think the new wiring from Vintage Wiring was the problem. All the "grounds" were carefully attached
with new star washers. Everthing else was new except the NOS turn signal indicator. I guess years of sitting
on a shelf allowed the contacts to corrode a bit and cause the prolem. Who'd a thunk it ???

Jerry
Member: Arizona Military Vehicle Collector's Club, Treasurer.
Past Pres
Member: MVPA #26600
Member: NRA
‘43 GPW, '53 M37 W/W, ‘54 M170 Field Ambulance,
59 M43, '76 M151A2, '86 CUCV,
'43 GPW, 416 & 101 trailers.
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