Brake light question

[Living in the Past]

Mark I believe when he said the rear signal worked I assume he meant the turn signals. If that is the case don't think there is a issue with tail light loom.​

 

[Coolerman]

Well DUH! Robcat, my apoligies. I failed to register you said in post #1 the turn signals work.

The GW wire top left is from the brake switch. When you press the pedal that wire should have +12V on it. The Brown/Orange wire, attached to the same post as the GW wire, is what jumpers the brake signal to both rear lights. I think you have an internal issue in the turn switch. USe needle nose pliers to bend the 4 metal tabs back so you can lift off the circuit board. Inspect the back of the board for worn contacts. Use some fine sand paper to clean them up. Check the shorting blocks also for corrosion and clean them up. Use dielectric grease when putting back together.

Here is the web page I did for the turn signal switch and electrical functionality. http://www.globalsoftware-inc.com/coolerman/fj40/6A.htm

 

[Robcat]

Missed this thread...
If you still don't have this working, then do the following.

Open the hood. On the passenger side firewall there are two 4 pin plugs. These are the plugs for the rear chassis harness. Unplug the two plugs. Now look at the male plugs only as they are the ones that go back to the rear lights. One of the plugs will have both a Green/Yellow and a Green/Orange wire in it. Use a jumper wire to the + terminal of the battery and touch it to the Green/Orange and Green/Yellow wires one at a time. GO is left and GY is right. If they light up, the rear harness, lights, and the ground for the lights, are all good and the problem must be the turn switch or the Hazard switch.

Using Coolerman's suggestion, I've ruled out any issues with the rear harness. I had a revelation followed by a major setback this past weekend.

While searching for the inline fuse to the hazards, I discovered that the wire (fuse holder and all) had been snipped about one inch from the harness. I had a very difficult time even reaching the wire, and cutting back the insulation and attaching a connector was next to impossible for a mechanical poser like me. After HOURS of effort that involved a few sparks (I didn't realize the wire was hot! Once I did, I disconnected the battery) and a LOT of tugging and pulling on the harness, I got the new fuse holder attached and was ready to announce to the neighborhood that I'd finally figured out my wiring dilemma. No such luck. After reconnecting the battery, I discovered that I have lost all dash lights, head lights, tail, and side markers. I disconnected the wire I had just connected to see if that was the issue, and nothing changed.

I've looked and looked for a fusible link or remote fuse I might have blown, but I can't find anything. Any suggestions?

I should also mention that I now have brake lights...on the front turn signals. The rear brake lights shine when I pull the hazard switch. Those and the turn signals are the only lights currently working. Argh!!

 

[Coolerman]

No fusible link on a 70. If all the lights mentioned quit working, then check that you didn't unplug the headlight switch or pull the big red wire out of the headlight switch connector.

If you have brake lights on your front turn signals you need to swap some connectors around. There are 6 wires with female bullet connectors on the main harness that connect to the turn switch, There are two GO, two GY, one GW and one GL. All you need to do is swap the two GO and the two GY and that will move the brake lights to the rear where they belong.

 

[Robcat]

Coolerman, you rock! NAILED the ongoing brake light mystery. I've still gotta fix whatever I broke trying to fix the original problem, but I HAVE BRAKE LIGHTS...and they're on the rear of the vehicle this time!

Now to get those headlights and dash lights working again...

 

[Robcat]

...hazards are working, too!

 

[Coolerman]

Awesome! Now check that headlight connector or it could be a bad headlight switch. It is also easy to take apart and clean.

 

[Robcat]

Headlights! It was the fuse box end of that big red wire you mentioned earlier. I took it off and cleaned it up, and wouldn't ya know it...illumination.

The schematic you made for the '70 proved invaluable. I have a Haynes manual, but the wire lettering was illegible, like a photocopy of a photocopy. I even looked at it under a low power microscope and couldn't make heads or tails of what it said! You saved the day. Well, at the rate I was going, you might just have save the entire month.

Thanks!