My 1962 T-Bird was in the shop late last year (new trans, starter relay, battery, assorted cables) and seemed to work well for ~ 5 mo (~ 500 mi). In May, after returning home from a pleasant Mother’s Day drive, I came back out to the car and it simply failed to start, although there occasionally was a weak click when I turned the ignition key. When I looked under the hood, I discovered that the shop had apparently installed the new battery with its leads reversed, ie., with the positive terminal lead grounded to the chassis and the negative lead connected to the relay (see attached file). It seems very hard for my friends to believe, but my car had appeared to function normally in spite of this. Is it possible for the car ignition (and other electrical components) to work with a reverse polarity battery connection ? Do you have an idea of how serious my problem is likely to be and what the most likely diagnosis / repair sequence would be ? Thanks for your help.
It IS possible to charge a battery backwards, the polarity of the battery then being reversed…But the battery will not perform very well in this condition nor will it last very long…Since your car as NO solid-state electronics, that would nt be an issue…But if a properly charged battery with properly marked posts was installed backwards, the starter would spin backwards and NOT start the car. The heater blower, radio, wiper motor would all not operate or run backwards…So I would say the battery was charged backwards or it was mis-marked. Check the battery polarity with a volt-meter and see if it agrees with the markings…
Thanks for your response, Caddyman. I had checked with my volt-meter and the battery markings seemed to be correct, adding to the confusion. Since my radio did not work and and I had not used the heater or wipers, I cannot verify those issues. I had received an opinion locally that starter would still function even if the leads were reversed, so your comment is interesting. All that I can say for sure is that it was a new battery, the leads were connected as shown in the photo and that it certainly appeared to work for 500 miles. The shop claims only that it started fine and by definition that it was working when they returned it to me (ie., they are not responsible for anything). I am trying to anticipate the need for replacing parts (relay, starter motor, etc. if there has been damage).
I suppose it IS possible the starter would operate correctly…And I know generators can indeed reverse their polarity just by connecting them backwards…The ignition system would still function but I expect the points would burn quickly as the condenser is indeed polarity sensitive…The voltage regulator may have been damaged and it may not have…
I would confront the shop and tell they have reversed the polarity of your car and you would like the problem corrected. They should at least replace the points and condenser if those parts are still obtainable. They will probably claim they could not have possibly done that…At some point, somebody has to connect the cables the right way and see what happens…
This may seem like a silly question, but does this car have a positive-ground electrical system? Some older cars do, but I’m not sure this is one of them.
Back in 1977 I purchased a 1948 Dodge from an elderly woman who had given up driving. Her son had installed a new battery in the car and reversed the leads. The car started and ran just fine, but the ammeter gauge showed discharge when the car was running and turning off the ignition and turning on the headlights made the ammeter gauge show a charge. What the woman’s son didn’t realize was that the Dodge was a positve ground car. The Dodge had a generator which wasn’t damaged. The starter motor turned the same direction. I can’t remember whether or not the tube type radio worked or not.
I remedied the situation by completely discharging the battery and bringing it up slowly with a low amperage battery charger. Once I installed the battery, I repolarized the generator–I think the procedure was to momentarily short the battery and armature connections on the regulator.
I am not certain whether your Thuderbird had an alternator or a generator in 1962. If it had an alternator, there is no way the battery connections could have been reversed without damaging the alternator diodes immediately. However, as I have pointed out, this wouldn’t damage the generator. Chysler products replaced the generator with the alternator in 1960. I know by 1965 all the manufacturers had gone to the alternator. However, I’m not certain when Ford products made the switch. Ford switched from positive ground to negative ground in 1956–the same year that Ford products went from a 6 volt system to a 12 volt system.
NO IT IS NOT POSSIBLE…HOWEVER…Some vehicles…usually OLD ones CAN have a POSITIVE EARTH system. If your system was a “regular” type…It would not…COULD not function properly at all…
So if this is how you found the batt after it had been working fine…then you may have a positive earth system…Nothing wrong with that…its just “backward” to many of us
OR someone monkeyd with your batt connections. and screwed them up…which is NOT GOOD.
We need to make sure what type of system you have
Caddyman should know his stuff…so I would lean his direction… But know for CERTAIN… Your current bat may just be DEAD enough that it hasnt messed up anything IF you do NOT have a Pos earth system…Fingers crossed. FOLLOW CADDYMANS ADVICE HERE…I side w him…
Then again…if someone reversed the cables…there arent exactly a ton of electronics to get fried…None Methinks actually.
If you expand the picture, you can see the generator mounted on the lower right of the engine…Polarizing the generator…You don’t hear that term much anymore…But back in the day, it was a common procedure…(and if may need to be performed on this car after the battery is correctly installed…)
I would check the battery carefully to establish it’s polarity and state of charge, charge it correctly, and connect it correctly and see what happens…I noticed the starter solenoid has been relocated from it’s normal position…
Blackbird…There are no electronics to fry…The car will tolerate the reversed polarity except for the radio…The generator may need to be polarized before it will charge again…The starter motor, being series wound, will indeed spin in the same direction regardless of polarity…The smaller motors, wiper and heater blower, will not…
Caddyman–you are right. The picture does show a generator. Repolarizing the generator is simple, but the way it is done depends on whether the field coil of the generator is internally or externally grounded. GM cars had an externally grounded field coil and Chrysler products had an internally grounded field coil. I don’t know how the Ford products were set up. The OP might go the the library and see if there is an old manual or the book “Fix Your Ford” by Bill Togboldt. This will explain the procedure to repolarize the generator.
Thanks a lot for all of the helpful comments, gents. I went out to do some errands and was quite happy to see the active discussion, which taught me a great deal. As C-Man states, the generator is clearly visible in the photo just below the position of the positive terminal and, as he states, there is very little electronically that is truly vulnerable in this wonderful beast. I will look over what my TBird manual says about all of your points (it has a section on repolarizing, see attached), and will contact my local car guy to see what comes next. BTW, when I contacted the shop they told me that they would look at the car if I got it towed, but were emphatic about not having messed things up. I am certain that I did not touch anything and that any changes to the battery, starter relay, etc. was their doing. They are actually transmission experts, but said the other stuff was too simple to screw up…
For information sake, see if the battery has been reversed polarized i.e. the negative terminal is now positive and the positive terminal negative. You can use a regular VOM/multimeter or more modern DVM. It would be informative to know if the battery reverse polarized the generator or the generator discharged the battery and recharged it to reverse polarity.
As Caddyman stated once a battery has been reverse polarized it will have reduced ampere-hour capacity even if the polarity is reswitched.
What I saw in the picture is the ground wire is RED and the positive wire to the solenoid looks to be black, but much of that wire is hidden from view. Once you get everything re-polarized I’d recommend changing the red cable ground cable to a black cable or at least wrap the red cable in black electrical tape. Perhaps the shop just hooked up red to + and black to - terminals on the battery; which in this car would hook the battery up backwards or like a + ground car.
A car of this vintage and especially one with a generator would handle this mix up without too much if any damage. My guess is the radio might be the most likely item to be damaged. In '62 solid state radios were just starting to be installed in cars, so if your radio works you are in good shape.