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MG MGB Technical - MGBGT 1977 Wiring

I have completed wiring my GTV8 conversion and am approaching "start up".
Before I make the final battery connection how can I be sure that I don't have a dead short in the wiring which will result in a fried loom once I make that connection, or having safely made it, then turn the key on and find a similar problem?
Many thanks
Peter M
Peter M

Connect a battery charger to the terminals and you should get a zero reading on the ammeter with everything switched off then check the circuits by switching on one by one and note the readings. Then connect the battery with confidence and light the blue touch paper.
Iain MacKintosh

Thanks Iain.
Peter M
Peter M

That's a good idea with the battery charger!

I was going to suggest putting a temporary fuse right at the battery and checking each circuit works individually. Maybe a 15 amp one to start with then working up in fuse rating as you test the higher drain things like headlights (you probably need a 35A for them?). Pull out all the other normal fuses to disconnect all the circuits then put each one in as required.

You won't be able to test the starter of course but by the time you get to testing that you will know everything else is good.

Simon
Simon Jansen

I used a high-wattage bulb like a headlamp bulb in place of the ground strap. If the bulb comes on at full brilliance (test it first) then you know you have a short. Only the starter should cause this, and that is one circuit you have to leave until the battery is connected and hope it is OK. Some things will work normally or slightly dimmer than normal with the bulb in series, things like flashers will glow but not flash, and the wipers won't run but at least you can see they aren't going to short. Not that things like flashers and wipers are an issue as they are fused anyway, it's things on the unfused brown and white circuits you need to test.
Paul Hunt

Thanks Paul
Could I use a multimeter (on voltage) between earth and the negative terminal to achieve the same result?
What voltage should I be looking for if I can do this?
Where are the pitfalls in the starter circuit?
Many thanks
Peter M
Peter M

If you can isolate the circuits, another way to test them is to use a 12V battery from a cordless drill.Just hold the wires to the battery to make contact. Barrie E
Barrie Egerton

This thread was discussed between 25/08/2009 and 27/08/2009

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