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77 midget electrical question

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77_MG_Midget

77_MG_Midget

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Ok... got by the heater hose routing problem. dropped a battery in the car to check out the wiring before I try to start it for the first time (hopefully this weekend). When I connected the positive cable, the starter selenoid began clicking immediately with the key off. I also had dashboard lights. I had replaced the ignition switch, so I thought maybe a problem there. I disconnected it under the dash, but no change.

I'm thinking I have something wired wrong? maybe the selenoid? not sure. The wiring diagram in the workshop manual doesn't exactly match. The main thing that stumps me is the diagram shows 2 white w/green strip wires running to the coil. My wires are not connected and purposely taped off in the harness. My coil wires are only white, white w/black strip. Maybe due to changing the amplifier? The car started fine before the restore, so I'm still thinking I've got the selenoid wired incorrectly.

Any Ideas please?
 
heck out this link. It was given to me last week. Look for you car and the wiring diagram is there. I just did my 70, and there are only 2 wires to the coil, white and white/black, If I remember white is positive side and the white balck is negative and runs to the distributor..
https://spritemidget.free.fr/techniques/elec/cadre.html
good luck
 
The reason you have two white/green wires going to the coil is because on the original set up, the coil ballast is integrated into the wiring harness. One white/green wire runs to the ballast, the other to the ignition switch. Thus, when you start the car, you have a full 12v to wake up your cold ignition system. Once the switch is in the "run" position, power to the coil goes through the ballast resistor.

So the question is: when the after market ignition system was installed, was the stock type coil exchanged for an internally ballasted coi?. Check your resistance across the +/- terminal. If it is 3ohms or greater, you should be good to go. If it is 1.5ohms or less, remove the white wire and hook the white/green wires back up.
 
thanks morris... I'd have never guessed that one. It's an aftermarket coil, but I'll have to check for an internal ballast as you said.
 
My coil has the following printed on it
"Not for use with an external ballast resistor"
"made in Mexico"

so... can I use it with an external ballast resistor made in the UK? /ubbthreads/images/graemlins/wink.gif
 
No hablar Espanol Senor! MG es Ingleses! /ubbthreads/images/graemlins/savewave.gif

Stuart. /ubbthreads/images/graemlins/cheers.gif
 
Well, figured out the wiring over the weekend. Sure enough, I had a wire on the selenoid in the wrong spot. A white w/red strip that powers the dash. Then, (this really makes me feel foolish), I had the fuse box in backwards. Seems that they split the lights (marker, tail, headlights) into separate sides at the output of the fuse box. Only has one wire coming in, red w/green strip. On the bottom of the fuse box is a jumper that I didn't notice. Because it was in backwards, this caused constant power to be jumped from the "always hot" to the switched circuit.

Working on the electrical sucks, at least for those of us that are ohms challenged. /ubbthreads/images/graemlins/blush.gif
 
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