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Author Topic: Third Fuse Not Live  (Read 152 times)

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june2021

  • An AMGBA Club Member
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  • Posts: 26
Third Fuse Not Live
« on: April 24, 2021, 11:33:20 AM »
I need your guidance on an issue I'm having with my '78 MGB.  It has a Pertronix and Weber carb.  When I go try to start the car I have nothing (turning the key in the ignition), I do hear the fuel pump and have lights.

So far to date- I've cleaned all battery connections, checked battery (tested good), and I'm able to start the car by taking the (brown/white) wire from starter relay and put it on bottom row of fuse block- car starts/ runs as normal when I do this.

Lastly, I used my test light on the third row fuse block when key is turned on in ignition and I have nothing.
Thoughts on next step to troubleshoot? Starter solenoid? Ignition switch?  I would appreciate any help.  Thank you.

Mark Younkin
Glasgow, KY

JohnTwist

  • AMGBA Club Tech Staff
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  • Posts: 117
    • University Motors
Re: Third Fuse Not Live
« Reply #1 on: April 24, 2021, 11:47:59 AM »
Two problems.  Wonít start and third fuse is not live.

WHITE/RED should illuminate your test light when the key is turned to START.  If so, check the other wires Ė BROWN always hot; BLACK always earth.  If those check out itís the relay (odd).

If the WHITE/RED does NOT illuminate the test light, then go back to the loom / connection between the key switch and the wiring harness.  Check it there, under the steering column.

The WHITE circuit is alive since the engine will start, but perhaps the ignition relay (in front of the fuse box) is faulty (not odd).  WHITE hot with ignition on; BROWN always hot; BLACK always earth; WHITE/BROWN feed to the fuse box.
Call me if youíre still having problems.

SAFETY FAST!
John H Twist
University Motors Online
100 East Beltline Avenue SE
Grand Rapids MI 49506-2410
Cell:  616-307 6737
www.universitymotorsltd.com
SAFETY FAST!
John H Twist
University Motors Online
100 East Beltline Avenue SE
Grand Rapids, MI  49506

616-307-6737
johntwist@universitymotorsltd.com
www.universitymotorsltd.com

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