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:willy:I just bought a 65 GTO Convertible, 455-Tripower, that is mechanically in great shape however there are several electrical issues that I'm hunting down. First off and my biggest concern is that none of the turn signals work nor do the brake lights work. When the head lights are on I do however have running lights at all four corners. I've checked all the ground straps and they are in place and clean with good contact. I replaced the Brake SW and turn signal SW attached to the Steering column under the dash. I have also removed and cleaned the fuse box and have 12vdc at every fuse I am supposed to except the wiper fuse, which is another issue. One thing that I cannot figure out is that there isn't a Flasher in the fuse box and upon closer inspection there aren't any wires or contacts in the fuse box for the flasher either. Since this is my first old pontiac I'm trying to figure out if all 65 GTO's had Flashers and if so could it located anywhere else besides under the dash in the fuse box? I purchased the Classic car colored schematic and it clearly shows the the flasher is part of the brakes light path but I cannot find it. Any suggestions?
 

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The flasher on my'65 is under the dash to the left of the steering column. It is hard to spot. Plugs into the wiring harness. There is no four way flasher standard, just the one for the turn signals. The ribbon loom that goes from fusebox to trunk (under the carpet) can get wet/corroded/shorted out. You may have issues there, but you'll have to remove the interior to check it visually. I would use an ohmmeter to check it for shorts to ground, or for open circuits. This stuff is a PITA, but not too hard. You need to be patient, have a good wiring diagram, and check each circuit for continuity, power, and ground. On mine, I put up with the turn signals not blinking whenever I had the brake pedal depressed. After about 10 years of this, I finally took a look, and had it fixed in about 30 minutes.....a lead had come loose at the horsehoe connector under the steering column. With the key on and the turn signal activated, do the lights come on but fail to blink, or do you get nothing at all?
 

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Thanks for your insight... Hopefully, I won't have to pull the interior out just yet..

I took a look last night under the dash and still did not find a Flasher. It should be connected to the brake switch so it can't be too far away. Currently the brake lights do not come on at all however - never. The tail lights only come on if I turn on the head lights. Although I haven't ohm'd it out yet, that leads me to believe that at least the wiring from under the dash to the tail lights is good - Tonight I will verify continuity for sure. In the schematic most lighting functions run from the horseshoe connector to and through the Light Switch, which again I am assuming is the turn signal switch on the steering column. There isn't another light switch is there? Tonight I will verify connectivity there as well.

The other issue I'm dealing with is that I have to track down is the top left fuse has no 12vdc on either side of it. My diagram tells me this is for wipers and dash/instrument lights. Once I find this 12v then I should have instrument lights and wipers. I cleaned off the contacts here and verified the fuse as well. but I'll tackle that next after I get the Brake/Turn signal issue fixed.
 

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The flasher on mine is in line almost with the brake light switch. If you go to the brake light switch and trace your hand back to the dash, under the lip by the steering column, that's where it should be. Yours may very well be missing. A lot of hacking was done to these cars in the past, and it's common to run into this sort of headache. That your tail lights and head lights work tells me that the grounds and circuits are basically ok. You more than likely have an under-dash issue. Look for cut, modified, or taped wires. Look for where it looks to be "messed with", and use a good wiring diagram. Good luck.
 

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Discussion Starter #5
Well - I found the Flasher - Thanks - It's not getting 12v so at least I'm getting closer. Will continue further tonight.
 

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I had the same problem with my 65. Started out as only having 1 brake light and 1 turn signal on opposite sides to none at all. Using a multimeter and a test light, tracked the problem down to the turn signal switch in the column. Replaced it and everything worked. Hope that helps. Good luck!
 

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My 66 was hacked also, they ran a new wire so they had running lights, and patched all the wires together, it was a mess. Took a while to straighten out, but I got it. Good luck, wiring isn't much fun, but at least the early cars didn't have very much.. When in doubt, ground it. I strapped grounds to everything under my dash, helped a lot.
 

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Discussion Starter #8
The other day I know I had a solid 12 vdc at the "Stop" fuse. Now it's more like 8v. I disconnected the Brake Sw, no change, then I disconnected the Flasher, no change, then the turn signal SW - No change. I think I'm back to pulling the fuse box and re-verifying the grounds and connections there before going on. On thing I know now that I didn't know before and that is that I have to hang upside down in the front seat to get to a vantage point where I can work and see everthing. Getting out isn't much fun either...
 

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You're wasting your time by removing the fuse box. The problem is most likely in the turn signal switch. Unless there is electrical continuity through the turn signal switch circuit, the brake lights will not work. You need to get an electrical schematic for your car, which is available free online Pontiac wiring 1957-1965 .
 

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Discussion Starter #10
Well - after some tracking I found that I had no power for anything that was running off of the ACC SW. I went back to the alternator which wasn't sending anything out to the voltage regulator. I took the alternator up to the shop and they confirmed it as bad. I replaced the Alternator and the Voltage regulator and now the generator light goes out shortly after starting the car and I have voltage to the bottom three fuses in the fuse box which run the wipers, brake lights, radio, and turn signals. Interesting now that the the drivers turn signal works but not the passenger side and the brake lights are the opposite. Passenger side works but not the drivers side.. I replaced both bulbs and have the same issue. Since I have at least one of the functions working at each corner I'm thinking the grounds are good and I'll trace out the ribbon cable throughout the car.

One thing I have a question about is the radio capacitor on the voltage regulator - Is it necessary to have one connected to the voltage regulator? There was a connector hooked up to the top of voltage regulator (not a capacitor) from the harness tat runs back up to the alternator but I cannot determine where the other end connects too - so I disconnected it. Concern? Isn't that connection for the capacitor?

Also, even though the alternator is mounted directly to the chassis - is there a need to connect a negative ground wire to it? I've not seen many that do. just curious.
 

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