1964 Electrical Issues

[Bruce Boatner]

The blinker on my 1964 blinks too fast--about the same rate as a dog scratching his ear. The gas gauge needle is also erratic. One day I noticed that the gas gauge needle moves when the blinker is engaged so the source of both problems must be the same. I thought I saw somewhere that a poor ground could cause the fast blinking problem, and the wiring diagram appears to show a common ground for the fuel gauge and turn signals.

Does anyone know where the ground wire is located for the gas gauge and/or fuel gauge? Any other suggestions would be appreciated. BTW--I replaced the flasher but the blink rate stayed the same.

[Mike M.]

Re: 1964 Electrical Issues

I had a similer problem and it was the wrong bulbs. Mike

[Bruce Boatner]

Re: 1964 Electrical Issues

Mike,

Thanks for your response. In my case, the bulbs in place now are same ones in use when the flash rate was normal so I can at least rule the bulbs out.

[Brian M.]

Re: 1964 Electrical Issues

First off they are called lamps not bulbs. Bulbs go in the ground lamps go in a socket. Sorry but a good friend has been pounding this into my head.
Check to see that all lamps are working. If all working it could be your flasher. Good luck

[Dino L.]

Re: 1964 Electrical Issues

Bruce, sorry about Brian's slam on the bulb-lamp....geeesh...boot/trunk, bonnet /hood, tomato/tomatoooo...anyways...Here are a couple of things to check, there are several ground wires in the rear body harness, check them all, especially the lugs that go the back of the tail light bezel fasteners, also there is a single black plastic connector that slips over a lug at the fuel sender locking ring. They typically rust out...just lay on your back right below the long spare tire carrier swing bolt and look up to the tank you will see the sender connections. Also I would remove the lenses of parking lamps and tailights remove bulbs and check for corrosion as well as proper bulb type and number. In addition at the fuse block upper right corner there is a turn signal relay/flasher (blue or silver tung sol, make sure yours is correct) that makes the "BULBS" LOL blink. If you are radio equipped there will be a capacitor underneath that, remove the capacitor and see if that works, if not replace the flasher. Check the connection at the brake light switch on the brake pedal, then if none of that works jump into the steering column and check the turnsignal switch. Then all else fails I will give you 5000 for it.

[Jack H.]

Re: 1964 Electrical Issues

The original flashers used then were based on an active bi-metal element. One flasher was used for 3-lamp cars (base) and another for the 2-lamp car configuration (with backup lamp option). The blink rate is dictated by the load characteristics of the lamps you have installed as well as getting the right flasher to match the car's configuration.

Today, many simply install 1157 lamps because they fit and work but that isn't necessarily what the car shipped with from the factory. Check your owners manual for the correct original lamp number and you just might find the car originally shipped with 1034 lamps instead of the later 'improved' version of that lamp--the 1157. Then, make sure that what you have installed matches the factory original spec IF you're using a correct/original flasher module.

Later service replacement flashers would have a different design basis and be relatively insensitive to branch current/lamp load. So, you can get different results (blink rate) when you substitute flasher modules leaving the lamps the same.

There could be 'some' interaction between the flasher and gas guage because the electro-mechanical voltage regulator ('515) isn't as fast in responding to electrical load changes as the solid state regulators (optional with C60 in '65, then, eventually built into the alternator itself in '69).

To get a 'fast blink' you have to be pulling more branch current than the flasher was 'expecting' to see. A 'bad' ground would generally result in higher circuit resistance and therefore lower branch current...

The mid-year cars use a unique gas gauge circuit based on Whetstone bridge circuit topology--an elaborate electrical engineer's term for a design that makes the gauge reading independent of actual supply voltage (is the battery hi/low; is the alternator charging?). The gauge reading is based on voltage divider action between the position of the tank's swing arm changing the resistance of an immersed rheostat and the fixed winding resistances of the inductors embedded in the gauge itself.

To make the system work, you need TWO separate ground paths! One is at the gauge via the instrument cluster and its connection to the dash harness. The other is at the sending unit in the tank.

[William V.]

Re: 1964 Electrical Issues

Bruce

Dino gave you some excellent advice. A bad ground and / or corrosion on electrical terminals can cause the most exotic troubles imaginable. I had an 80 Chevy PU with a quick flashing problem and dim brake lights. I found that, while in reverse gear with the clutch depressed, my right foot on the brake, and the key turned off, the engine kept running. The engine was not dieseling but running at a smooth idle. When I removed my foot from the brake the engine stopped. The problem was the bed ground went open or to a high resistance which allowed current from the brake lights to feed back through the reverse lights and back feed the ignition. The fix was to add a ground strap from the bed to the frame. My guess is you have a ground and or corrosion issue.

Good Luck

BV

[Bruce Boatner]

Re: 1964 Electrical Issues

Holy Cow! This problem could be more complicated than I imagined. Just to give a little more background, the problem started after I replaced the flasher which somehow cured the problem I had with constantly blowing the fuse to the clock and turn signals. Everything worked fine for a while but eventually the blink rate got faster and faster. I tried a new flasher but no difference (the flashers were off the shelf from Auto Zone). Might help if I actually understood the basics of electrity--heck, I always thought a bulb went into a lamp. I will poke around some more armed with everyone's advice and pray that the electrical gods are kind to me.

[Brian M.]

Re: 1964 Electrical Issues

Dino, Please don't apologize for me. If you consider that a Slam, one of us has very thin skin.

[Dino L.]

Re: 1964 Electrical Issues

Bruce , I researched more about this problem, armed with the 3AG/AGC-4 4ampere fuse blowing for the radio and clock, which by the way fuses the instruments and lamps leads to a grounding problem to me.

When the turn signals flash quick you either have 1. the wrong flasher or a grounded lead or grounded bulb. Confirmed by GM manual

you should have 1157 directional signal lamps and your flasher should be model 224 tungsol blue metal round for 64 with back up lights, or a 145 signal stat various colors rectangular....if you dont have back up lights option then you need a AP373V tungsol flasher aluminum round or 143 signal stat variuos colors rectangular......or an Autozone equivalent equipment.

There is a 16 gage black wire in the rear harness that grounds to the license lamp housing, taillamp housings and fuel sender lock ring.check for corrosion, broken wire or loose connection, and open the lens and check for corrosion...the front lamps in a daily driver will get water in them some time. also the rear ones will get some condensation without the wicks in place...HAH from Mr thin skin

[Bruce Boatner]

Re: 1964 Electrical Issues

Dino,

Thanks so much for your help. I will check the rear harness for proper grounding first. If that doesn't work, I will make sure I have the proper "lamps". I'm pretty sure the Autozone flasher is suspect.

The wiring diagram shows all of the ground wires for the rear harness converging to a single ground wire. Do you happen to know where the connection is located as well the ground point (I am assuming somewhere on the frame)?.
I guess I can just trace all of the black wires from point to point. Problem is that they seem to disappear into the frame or under something else that I really do not want to remove.

I did check all the lamp sockets and noticed they were all clean sound (obviously were replaced at some point).

Thanks!

I checked a wiring diagram and noticed that I will check the "lamps" and make sure they are the correct type and invest in

[Louis Kolb]

Re: 1964 Electrical Issues

I have not had good results purchasing parts from Autozone. I got tired of returning 'new' parts that failed.

[William V.]

Re: 1964 Electrical Issues

Bruce

Did Thomas Edison invent the electric light lamp or electric light bulb??

The story about the pick up was to illustrate how a grounding trouble could cause very confusing and exotic problems that are easily fixed once it's figured out. I suggest you measure the resistance between the ground wire connected to the tail lamps and the frame, or temporality connect the tail lamp housing to the frame with alligator clips and see if this helps the condition. You could also have a problem with the park lamps in the front. I find the connector that connects the park lamp housing to the front wiring harness may get corded and causes similar problems.

Good Luck

BV

[Bruce Boatner]

Re: 1964 Electrical Issues

Bill,

I understood where you were coming from with your pickup story--it was great! I know I will be fine with the "fixing" part, it's just the "figuring it out" part that gives me fits.

Thanks so much for your help. I will be sure and post the solution when I do figure it out (wish more folks would do this).

Bruce

[Mike M.]

I meant wrong Lamps *NM*