QuestionQUESTION: my 66mgb just went dead one day in my garage , iput in a new battery and relaced the starter still nothing, turning the key nothing no lights, wipers or radio .i did have a wire going to the solenoid heat up and break off?
ANSWER: Hi Jacky,
It sounds like you connected the two batteries up backwards. This is a positive ground car unless it had been converted.
Do you still have the original two 6v batteries? If so, how did you connect them?
Howard
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QUESTION: my mg has had a single 12 vlt battery for years, it IS a positive to ground hookup . I reconnected the new battery the same way (positive to ground) there is a constant wire to the cellunoid that is hot and melted as soon as the battery is connected?
ANSWER: Hi Jacky,
The 66 MGB has the remote mounted solenoid and if the large battery cable melts the insulation as soon as you connect it to the solenoid then that solenoid is for sure shorted out.
You also have a DC generator and not an alternator. This has a large 12 gauge brown wire connected also to the solenoid. This 12 gauge brown wire goes to the regulator for the generator.
When you have a short in the harness or in the 12 ga. wire it would melt that brown wire instead of the battery cable as the battery cable is much larger then the 12 ga. This proves that the short is in the solenoid itself.
If some one had installed a alternator in place of the generator then you can not have a positive ground system because to my knowledge there are no positive ground alternators. But even then if some one previously had installed a alternator it would have melted the large wire from the solenoid to the alternator instead of the battery cable because that wire would also have been a 12 gauge not as large as a battery cable.
The lugs on the solenoid have been insulated but on yours you need to closely examine them to see that they are not damaged and test the lugs with no wires on them with an ohm meter and replace it if either large lug is shorted.
Howard
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QUESTION: my mg was converted to an alternator many years ago, and it is positive to ground battery, and the wire that melted and is still hot is the brown wire going from the solenoid to the alternator. the battery wire to the solenoid is fine? your help is greatly appreciated.
AnswerJacky, You're not reading what I am writing. IF YOU HAVE AN ALTERNATOR, YOU MUST HAVE NEGATIVE GROUND!!!!! THERE ARE NO POSITIVE GROUND ALTERNATORS.
You connected the battery up backwards and you may have fried the alternator along with the wire to it.
The method to test it is to correct the wires with new wires first, then connect the battery up correctly but leave the wire from the alternator to the solenoid OFF. Also disconnect the wires from the back of the alternator. Now, with the battery connected up correctly (NEGATIVE GROUND) and positive to the solenoid, take a 12v test light and put the test light lead on the large post of the alternator, touch the positive post of the solenoid with the test light probe. If the light does NOT light the alternator MAY be ok. If the test light lights then the diode pack in the alternator is destroyed.
If the light does not light up, go ahead and connect up the wire from the solenoid to the alternator and plug the wires into the back of the alternator and go in the car and turn on the ignition (Not Start) Look at the "IGN" light on the instruments and it should be ON. Turn the key off and the light should go off. Then start the engine and watch the "IGN" light to see that it goes out. If it does, the regulator is probably ok.
let me know.
Howard
A final test is to put a volt meter across the battery posts and read battery voltage (12.5v +) and have someone start the engine and set the RPM at about 1500 RPM and read the volt meter again. It should read from 13.8v to 14.5v and if it does the regulator and alternator is working.
