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MG MGB Technical - Ballest wire, color code? 1980 SE

I've checked the archives on this but didn't find a definitive answer. What is the color code for the resistive wire used as a ballast on the late model B's ignition system? I'm trying to help a fellow club member sort out some wiring mods made by a PO and found a pink/white stripe wire in the main loom running from near the coil area up to around the left headlight where it was connected to a white/light green wire which ran back to the coil. Our manual shows two resistors in the circuit, one is numbered and identified as a 'ballast resistor' the other is not identified in any way. I'm not sure of the pink/white color code as the wire was melted pretty badly it's entire length. If this is indeed a resistive wire, does anyone know the resistance value?
Bill Young

Bill:

The ballast resistor rating is between 1.3 and 1.6 ohms. It is connected to the starter solenoid by the white/lt green wire and the white/brown wire connected to the fuse block.
A. R. Dennison

Yes you've got it, that pink and white wire is the one (at least it is in my american '75). Hiding it in the loom was a rotten idea, no idea why they did it as they often seem to overheat, melt and that can't be good for anthing next to it in the loom. Probably a good idea to put in one of the more commonly used ceramic ballist resistors. You'll often see them in Japanese cars, attached to the coil bracket.
Peter

The white/light-green connects the ballast wire to the coil +ve *and* the solenoid, the coil being the most important of these connections. It is a long length of resistance wire contained within the loom so it can dissipate its heat over a large area and is not concentrated in one place as a resistor does. If it has burnt then it has been carrying too much current, possibly because the coil had gone short-circuit at some time, or an electronic ignition module had been connected incorrectly or failed. The latter is a possiblity, many North American spec rubber bumper cars were fitted with the 'Opus' ('opeless) 45DE4 ignition system that did have an additional supply resistor with white and white/blue wires, although by 1980 these should have given way to the much better 45DM4 ignition system. All the ballasted systems use a 6v coil of about 1.5 ohms as well as the ballast resistance of a similar value regardless of which factory electronic system or points was used. Aftermarket electronic systems are something else. It is important to check you are using the correct coil.
Paul Hunt

This thread was discussed between 10/05/2004 and 11/05/2004

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