[gto4evr]

hey guys, before I go down a rabbit hole, can someone confirm how the front turn signals react?

when my lights are off, side markers flash in time with the turn signals (both with turn or hazards)

when my lights are on, the side markers flash opposite of the turn signals.

got a friend with a 72 that says his do the same thing but I'm really not seeing why this would be the case as I look at the wiring diagrams. my initial feeling was some kind of grounding problem but both sides do it equally and I'm not seeing anything weird with the headlights or running lights. everything is stock with standard bulbs and no wiring modifcations. I've been driving this car for 40 years and never noticed this before and know the 69 side markers do nothing other than come on with the headlights and they're basically wired the same way in the harnesses. I've got a post on this in the electrical forum but figured I might get more response here to at least confirm if this is normal or not. I guess it's not hard to believe two cars could be doing the same thing as these cars are notorious for grounding issues, especially after being 50 years old

Thanks,
Dennis

[gto4evr]

update just to close this post out for posterity:

I decided to check the wiring diagram on 72 which should be the same and low and behold, it's completely different than the 71 diagram. What I'm seeing on the 72 diagram makes sense as to what's happening so mystery solved, Neither wire going to the marker light is a dedicated full time ground so when lights are on, one side is powered and the other gets a ground through the turn signal circuit, when the turn signal is on, that ground wire becomes hot to power the turnsignal bulb which is why the light goes out when the turn signal is energized. weird way to force the side marker to work both ways but there it is. simply a wiring diagram error. probably a hold over from 70 which also didn't flash like 69 didn't.

[Shiny]

Interesting and yes, seems weird, but glad you got it figured out.

I'm curious which 71 wiring diagram you found in error. Was it in the repair manual or was it an aftermarket version?

[gto4evr]

Originally Posted by Shiny

Interesting and yes, seems weird, but glad you got it figured out.

I'm curious which 71 wiring diagram you found in error. Was it in the repair manual or was it an aftermarket version?

It was the main wiring diagram in the factory 1971 service manual. I collect tons of factory literature so I have every service manual and TSB binder from 64-74 so had the 72 service manual to look at to which showed the change they made to the headlight harness wiring diagram that apparently wasn't updated in time of the publication of the 71 book. Since 71 and 72 have identical headlight/turnsignal and sidemarker designs it's obviously a manual error that maybe everyone knew about back in 71 but 50 years later, it's now tribal knowledge lost to time.

[Judge273]

Can you post pictures of the manual that show the errors?