MG MGB and MGB GT Tech Talk
hi all
been working hard these last few days and all is on track, got back axle, brakes and most of wiring in, just about to put the engine and gearbox in now and fire her up.
I'm confused about one symbol on the wiring diagram. The white wire which goes from the fusebox to the coil has a zig zaggy logo on it, no idea what this component is, and clues?
I've worked from page 18 of this PDF http://www.advanceautowire.com/mgb.pdf
cheers,
Kev
A zig-zag is always a resistor on a wiring diagram. You've found the ignition ballast resistor. You may not be able to find it on the car.
What year is your car?
Ballest Resistor.
My '74 doesn't have one, so I couldn't tell you what it looks like. I'm sure someone else will be along with a full description.
Paul
Edit: Looks like John beat me to it.
That's why I said he probably can't find it and asked the year of his car. On later models it's built into the wire harness. It runs up to the front of the car and loops back to the coil. They do that because a resistor drops voltage by wasting it as heat. To keep the heat from being concentrated in a small area they spred it over a large one to keep the resistor from burning up. It's a good method and those things last forever.
Generally these are ceramic in construction, for heat dissipation.Usually bolted to the fender or firewall (in other cars) It's probably gonna be dirty black from years of engine bay time, but like was mentioned, generally last a loooooong time unless physically broken. My 79' has it just below the Coil.
If it's not an "in-line" deal, it will be a white ceramic bit - about 2 3/4" inches long (just found mine - unattached under the spare tire).
If you're referring to the fuel gauge sender, I think that symbol is actually a rheostat.....
John D. Weimer Wrote: