1966 Emergency flashers

[Joe T.]

The emergency flashers work on the front passenger side and both rear. The driver side will not flash. The turn signals and parking lights work fine all around. Need help on this one.

[Donald A.]

Re: 1966 Emergency flashers

The turn signal wiring harness comes down the steering column from the switch at the steering wheel. It attaches via a double row curved connector to the harness that goes over towards the fuse panel and main harness area in the regular setup. With the V74 (4way flasher) option the double row curved connector is disengaged, the upper end (from the turn switch) attaches to the connector from the V74 harness and the other connector from the flasher harness attaches to the lower double row connector that goes over towards the main car harness area. If you detach both V74 connectors and attach your turn signal harness connector directly to your car harness connector, everything (turn signals, brakes etc) should work properly. Assuming it does then your problem is the connectors and/or wiring from the V74 harness connectors. Corrosion, slipped metal connectors inside the plastic, broken wire etc. This happened some time back with my car and simply disconnecting the V74, cleaning everything with contact cleaner and a small wire brush on the connector contacts and reattaching returned all to normal operation. It is possible for the copper sliders in the V74 box to get loose or lose contact but usually the culprit is the V74 wiring and/or connectors. Good luck with your repair! Here's a photo of what the connector areas look like after detaching from the car harnesses:

[Richard M.]

Re: 1966 Emergency flashers

Yes it could be a loose connection somewhere.....

But because the LF Directional works, this tells me that external harness connections are intact. Since the 4-Way switch interrupts the Directional circuit then activates the 4-Way circuit, I'd imagine the LF internal contact of the 4-Way switch has the bad connection. In particular, the Light Blue wire circuit.

Below is a 67-68 circuit diagram which may help. As you can see the Light Blue circuit is for LF directional. Also shown is the Light Blue(LF) source when in 4-Way mode(lower left corner of the hazard switch box diagram). The 4-Way simply switches out the Directional Flasher and switches in the 4-Way Flasher output directly to the LF, RF, and both rear lamps. I suspect the 4-Way LF internal contact is at fault.

This can be verified with a voltmeter or test light at the Light Blue terminals at the underdash connectors. You will have alternating voltage there in Directional mode, but not in 4-Way mode.

I think the 4-Way switch can come apart to clean the contacts. It's possible if you wiggle the harness at the back of the 4-Way it may temporarily work, but just as a diagnosis test, not a final fix.

Rich

[Joe T.]

Re: 1966 Emergency flashers

The turn signal wiring harness comes down the steering column from the switch at the steering wheel. It attaches via a double row curved connector to the harness that goes over towards the fuse panel and main harness area in the regular setup. With the V74 (4way flasher) option the double row curved connector is disengaged, the upper end (from the turn switch) attaches to the connector from the V74 harness and the other connector from the flasher harness attaches to the lower double row connector that goes over towards the main car harness area. If you detach both V74 connectors and attach your turn signal harness connector directly to your car harness connector, everything (turn signals, brakes etc) should work properly. Assuming it does then your problem is the connectors and/or wiring from the V74 harness connectors. Corrosion, slipped metal connectors inside the plastic, broken wire etc. This happened some time back with my car and simply disconnecting the V74, cleaning everything with contact cleaner and a small wire brush on the connector contacts and reattaching returned all to normal operation. It is possible for the copper sliders in the V74 box to get loose or lose contact but usually the culprit is the V74 wiring and/or connectors. Good luck with your repair! Here's a photo of what the connector areas look like after detaching from the car harnesses:

Thank you for the information and photo. I will give it a try tomorrow.

[Joe T.]

Re: 1966 Emergency flashers

Thank you. I will work on it tomorrow. I am new to NCRS and really appreciate the responses.

[Joe T.]

Re: 1966 Emergency flashers

I took the connectors apart, sprayed contact cleaned and wire brushed. Got the same problem with left front. At one time I had a very dim flash in the left and right front. After disconnecting and connecting the connectors several times, I am back to no left front and good flash the rest of the way around. Any suggestions?

[Donald A.]

Re: 1966 Emergency flashers

I took the connectors apart, sprayed contact cleaned and wire brushed. Got the same problem with left front. At one time I had a very dim flash in the left and right front. After disconnecting and connecting the connectors several times, I am back to no left front and good flash the rest of the way around. Any suggestions?

Well then the problem is in the V74 box itself. The red knob just unscrews, then remove the bulb inside the knob area, then remove the round knurled nut from the shaft of the V74 box and the box will fall out of its mount on the e-brake plate. Disengage the connectors and take the V74 unit to your work bench. Remove the two screws on the side of the box and very slowly/carefully loosen then lift up the side panel. Underneath you will see where the wire connectors attach to the copper sliders. One of those wires (probably the light blue one) will either be broken off or will be loose or the copper slider will have broken or something will be damaged that should be apparent when you study it. Hopefully it will be an easy fix. If not the signal-stat unit is common to millions of 60's cars and trucks and you can get parts or even the complete 105 unit on ebay or similar. Good luck

[Joe T.]

Re: 1966 Emergency flashers

Thanks Don. I will give it a try tomorrow. By the way, I have a 66 L72 in Milano with black leather interior. The convertible top is black also..

[Joe T.]

Re: 1966 Emergency flashers

I took the box apart and could not see any loose or broken wires. I blew out some dust and sprayed some contact cleaner. Will install back into the car tomorrow.

[Joe T.]

Re: 1966 Emergency flashers

Well, took the box apart, cleaned contacts, installed it back in the car and got a very dim blink on all 4 lights. Even the driver side front. Can't figure this one out?????

[Donald A.]

Re: 1966 Emergency flashers

Well, took the box apart, cleaned contacts, installed it back in the car and got a very dim blink on all 4 lights. Even the driver side front. Can't figure this one out?????

Make sure you have a solid ground to the V74 box. Its supposed to ground on the e-brake mount. If it is loose there or poor ground it may affect the flashing and it will stop the lamp inside the red knob from illuminating. Next check the flasher - it may be failing. Try a different one. Having weak flash on all four corners makes me think the circuits are now all active so what has changed is lack of power (weak flasher, bad connection, loose attachment of the red wire to the fuse panel etc) or lack of good ground. If it remains elusive I would still suspect loose connections or bad springs in the copper slider area inside the V74 box. It's been some time since I had mine apart but I seem to recall the contacts that slide are spring loaded, if the springs are weak, contact is intermittent or poor. Hope you get it fixed - good luck!

[Joe T.]

Re: 1966 Emergency flashers

Did a good ground and checked all wires with no success. Purchased a new flasher and now I have a good flash all around. I think I had one corroded copper contact. It was black on the tip prior to cleaning it and a defective flasher. Thank you for all of your help. Now I will move on to getting my rear compartment light to come on. I will post a new thread for it.

[Donald A.]

Re: 1966 Emergency flashers

Did a good ground and checked all wires with no success. Purchased a new flasher and now I have a good flash all around. I think I had one corroded copper contact. It was black on the tip prior to cleaning it and a defective flasher. Thank you for all of your help. Now I will move on to getting my rear compartment light to come on. I will post a new thread for it.

Good job, glad you got it!!

[Richard M.]

Re: 1966 Emergency flashers

Did a good ground and checked all wires with no success. Purchased a new flasher and now I have a good flash all around. I think I had one corroded copper contact. It was black on the tip prior to cleaning it and a defective flasher. Thank you for all of your help. Now I will move on to getting my rear compartment light to come on. I will post a new thread for it.

Joe, Great! You know what's strange...... Harry Sadlock had a weird problem like this on his 63 recently, in fact his Left Directional only, and his problem was also solved by a Flasher change. Hmmmm. The Flasher Demons abound.

BTW, that rear compartment bulb socket is notorious for dirty/loose socket pins. Note it should be a 2 terminal bulb(#90) so the socket housing is not grounded.

Rich

[James G.]

Re: 1966 Emergency flashers

I love it when two pros get together. Thanks Don and Rich for sharing. And you too Joe for posting the problem.