QuestionI have a 1971 MGB. After I acquired the car I installed a new battery. It has a 12V negative ground. I installed the battery ioncorrectly and hooked up the ground to positive instead of negative. I fried the alternator. I reversed the battery so that it is now grounded to negative and installed a new alternator with the 3pin connnection following Moss' directions to convert from 5 pin to 3 pin. Now the car will not start, fuel pump does not activate, lights do not turn on. I checked the battery connections and get 12V at the end of the positive cable that is attached to the solenoid. Is it possible that something else fried and what would it be? Also the small spade connector at the solenoid is loose and I cannot tell if it might be broken inside the solenoid.
Thank you
AnswerHi Jim. Your MGB originally had two 6-volt batteries, so I presume you have had it converted to a single 12-volt battery.
Basically, there is no power getting through to the car at all.
You need a volt meter to check this out. Connect the black lead to a good earth (ground) and make sure you are getting at least 12 volts at the big terminal on the starter motor.
If you have no voltage there, I would guess that the battery has not got a good earth connection.
Assuming that you have power to the starter solenoid, it then goes via a brown wire directly to fuse #4 (the bottom one). That should also have 12 volts to it. My guess is it will be dead, in which case the problem is either with a connector (at either end of the brown wire), or else the wire has fried.
You may get away with running a new wire outside the loom directly from the starter motor solenoid to the fusebox.
If that doesn't fix it, then you will need to open up the loom to see what damage was done when the wire got hot.
