mfbanres

No light at negative side of coil SOLVED

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To start, yes I have done my homework and researched the issue.  I have three wiring diagrams and a shop manual.

 

This is a 73 tii that I am trying to start at the end of a 5 year restoration.  Battery is new, starter cranks, all electrical bits function.  There is no spark at the plugs or coil, so according to the trusty Haynes, I test the negative side of the coil with the ignition on, and the points open.  Nothing.  I have traced and tested wires through the firewall and under the dash.  Haynes says no juice from ignition switch.  Be that as it may, I am not finding the short or missing connection.  One more detail:  I clipped all the underseat and seatbelt nanny wires, and removed the buzzer.  So, after hours of circuit testing, I throw myself upon the forum:  what am I missing?

 

thanks,

Michael

Edited by mfbanres

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1.disconnect all wires from negative side

2.verify you have a light on the positive side

3.If step 2 lights up then verify you have a light on the negative

4.If step 2 doesn't light up then you have no voltage to the positive terminal

5.If step 3 lights up then one of those wires that were hooked up was grounding out the negative side

6.Now you can trace either positive or negative terminal wiring to determine if you are missing +12 (ignition sw, etc)or something is grounding out the negative terminal(points,condensor,or tach)

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Have you metered the POSITIVE side of the coil?

 

(see step 4, above)

 

You can always cheat, wire the hot side of the coil to the battery, and see if that starts it.

 

I suppose you may have

(7) open coil,

but that's really really uncommon.

 

Another useful test- attach test light to negative side of coil and battery +, and see if the light blinks while cranking...

 

t

 

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Thanks for the support.  Following up on your replies I started the continuity process all over again.  I traced the wires to the fuse box.  I unscrewed the fuse box.  Looking under I noticed the green wires from the ignition switch were not plugged in.

 

Plugged it in to No.11 fuse and everything lit up like a Christmas tree.

 

Lesson:  never assume anything.

 

Cheers,

 

Michael

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