Classic/Antique Car Repair: 58 Ford Retractable electrical issue, fair weather, issue question


Question
QUESTION: Hi, I've got an electrical question about our 58 Skyliner. most of the time we keep the top retracted in the trunk since it is pretty much a fair weather car anyways. a few weeks ago we tried to put the top on and found that there is a MAJOR short in the system somewhere. the top operates smoothly and latches down, which signals for the trunk lid to close, but when the trunk lid starts to come down the entire electrical system shorts and the car looses all electrical power. a few weeks ago the lid came down about half way before shorting but recently it shorted just as soon as the lid started to move. this problem occurs only when the top is on, when the top is retracted into the trunk the trunk lid closes with no problem at all.
Thank you very much for your time, any help or simply a point in the right direction is much appreciated.
         -Nathan

ANSWER: Do you mean that you loose headlights, accessories, and the car will not start when it looses power? Let me know.
Brad

---------- FOLLOW-UP ----------

QUESTION: we have not had the headlights on while running the top, but yes the radio dies when this happens. the car seems to lose spark and dies if the top switch is engaged for more than a second or so. once the car dies it may take a few seconds for the battery to regain enough juice to start it again. we almost always have the car running while operating the top, so that we are not relying solely on the battery. I do not believe we have tried operating the top with the car off since we discovered this problem.
-Thanks again, Nathan

ANSWER: OK, lets look at what is happening. if you are running the engine with it at idle, the generator is not producing anything to help the battery, you are still running off the battery. One of the reasons for the industry going to the alternator was that it would produce electricity at idle where a generator will not. I would want to get a voltmeter into the act when cycling the top. It sounds like you could have a battery that is weak and close to replacement time. Lowering the lid is one of the last steps in cycling the top either up or down and the battery has been supplying all the electricity needed to get to that point and that may be the fail point, or the lid motor might be drawing more electricity that the other motors. I would also check all the connections right from the battery back for a dirty or loose connection. I do not think that it is a short. Another thing that you could try is to bring the engine speed up to about 1500 RPM and try it. If the problem does not happen then you know that you have a battery problem. Let me know.
Brad

---------- FOLLOW-UP ----------

QUESTION: This problem also occurs with the engine revved up. once the lid starts to  close,(but only when the top is on), the car dies, no matter how high the RPM's are, (we have had the RPM's quite high). what we find perplexing is that the lid will run up and down perfectly as long at the top is in the trunk.
-Again, thank you so much for your time. Nathan

Answer
These motors are reversible and two sets of windings in them. It sounds like the windings in that direction may have a short and tripping a circuit breaker. Or there could be a wire in the trunk area getting pinched when you put the top in the trunk. I usually use an induction amp meter when chasing a problem like this to check the current draw. If I remember right the circuit breaker on this car is attached to the starter solenoid.
Brad