64 convt electrical issues

[stewart]

Hi all, recently inherited this 64 convertible. I have plenty of experience with Falcons and Mustangs, but this is my first bird, and I have a few issues I could use some direction on. History of the car and previous repairs are a mystery as the previous long time owner is deceased. I will just throw it all out there hoping it's all related and makes sense to someone...

I have a 12.9v draw with everything off, killing the battery. Emergency flasher in the dash flashes non stop - even after disconnecting the switch. I thought possibly bad flasher - removed it, still have the draw. Seatbelt light in the console lights up with the key on or off.
Taking a test light to the fuse box - every fuse has power with everything off, the key off and the doors closed. When connecting the battery - there is a very clear click coming from the upper PS dash area- above/behind the heater box - sounds and feels like it is right behind the vacuum canister that is under the hood.

Dash gauges don't seem to operate with any consistency - I figure that may be the constant voltage regulator- but will deal with that later.

I have recently replaced the gear shift lever to fix the sloppy park problem, and the steering coupler as it split when we had to move the car with a dead battery...

I have ordered all the electrical and service manuals from the birds nest, just hoping to get a jump on this problem so maybe my kid can take it to prom in a few weeks.

Thanks!
Stewart

[jtschug]

A phantom current draw should be measured in Amps, or better yet milli-Amps (mA), not Volts.

However, this isn't a phantom current draw. You've identified things that are "on" which will draw power. Many circuits are 'live' with the key off, so it isn't completely surprising that you are finding power. The emergency flashers are one of the systems which is supposed to work with the key off.

The problem this car is experiencing is not a failure mode of the car, but I've seen problems like this before. The problem is someone tried to fix an electrical problem by hotwiring it. You might find multiple places where relays or other things are hotwired. You might find wires smashed into connectors. These hot wires provide an electrical path which goes around switches and relays and prevents the car from being able to shut things off.

Here is where you should start: follow every wire harness you can find and look for black vinyl electrical tape. Ford did not use this kind of tape in 1964 and Ford dealerships did not use this kind of tape to make repairs. There is a short section of vinyl wrap on the driver's side inner fender, but it isn't tape. This tape is a marker left behind by some amateur shade-tree mechanic who tried to fix something the wrong way. These kind of poor attempts at electrical fixes lead to these kinds of problems. Find all these hotwires and rip them out of the car. Repair areas where someone has cut wires and spliced things together that were not originally connected from the factory. Look for cheap plastic crimped connectors. Look for wires with no loom covering. Find everything that doesn't look factory correct for 1964 and remove and try to restore the harness back to the way it was.

When you are done doing this the car probably won't work. That shade-tree mechanic many years ago was trying to fix *something* that was broken. Now that you've removed the bad attempted fix, you will need to diagnose and fix it correctly.

That said, there are few electrical changes from stock on a 1964 Thunderbird which are probably justified. First, the ammeter circuit does not use a shunt, and there have been many fires caused by that wire which goes from the alternator through the gauge in the dash. If you've got iffy wiring on that circuit which passes through the firewall in the passenger footwell area, then it is best to leave it disconnected. Second, there was a TSB in 1964 to add a horn relay. Usually this was located near the washer bag behind the driver's side headlight, but different dealerships did this repair differently, but this is something that was done shortly after the car was sold. Third might be an alternator upgrade. With the known issue on the ammeter circuit, this requires a bit more care on a 1964, but with a convertible, it is helpful to put in a more powerful alternator. You might be familiar with this kind of upgrade from Falcons and Mustangs. It can be done in a good way that makes the car more reliable, but it can also be done in a hack way that causes problems. In contradiction to my advice above, I would not automatically tear out a more modern alternator and restore it back to a 1964, but I would carefully look to see if it was installed properly.

I'm not sure if you are going to be ready for prom, some of these electrical gremlins are a real bear to deal with.

[stewart]

Thanks for the reply. The more I look , the worse it gets- lots of tape and cheap butt connectors.

Until I get the diagrams, chasing wires and making “repairs” will be me just banging my head on the dash…

I think I am going to put a battery disconnect in until I can find a good factory dash harness. I have reached out to a couple of places already.

[Terry64HT]

jt,
I saw in your post that you said a TSB added a relay to the horn circuit. I believe it was for the brake lights. The draw for the 6 rear brake bulbs was too much for the hydraulic switch so a relay was added. Not all 64's got it though. The horns always had a relay and the horn switch on the steering wheel closed a circuit for the ground of that relay. There was no power to the steering wheel. Could lead you down a rabbit hole if your were trying to diagnose horn problems with a volt meter.

Terry
64HT

[jtschug]

Hi Terry,

Yes, you are right. I have only had 1966 T-birds and where 1964's are different is a little outside my area of knowledge.