Wiring Problem

[halfwaythere]

I just finished putting the wiring harness in my 72 today and everything works great except whenever I turn on the headlights the blinker indicating lights on the instrument panel come on and the blinkers will not work. when I have the headlights off the blinkers work fine.


Any body know what to do?????

I'm bout ready to pull my hair out!!!!

[frost89434]

I would check all of your grounds. A bad ground will cause very weird things to happen.

[Lippyp]

I have the exact same problem on my '67 intermittantly, I know what causes it but haven't come up with a good solution yet. Put your hand up under the dash and pull the top left hand bulb as you look at the dash. If it's the right one it has a ground wire coming out of it and it is different to all the other bulb holders, it's a bit of an odd looking mother. All of the grounding for the panel goes through this one connection. You may find that the bulb has blown and changing it will cure the problem.

If not it I can guarantee that it will be this that is causing the problem, mine seems to be intermittantly making a bad ground connection but haven't worked out how to cure that yet as the wire seems to go into the harness. Any suggestions welcome, I am thinking of adding an extra soldered on wire and using it as a second ground.

My blinkers do keep on working though, you just can't see it easily on the dash tell-tales. Everything else on the dash goes dim including the little light on the gear indicator, pain in the ass if you are driving at night.

Hope this helps.

[mikej71]

I'm experiencing the same problem. I didn't have any ground wire
connected to the pc board, so I'm going to try that.

[SWINGSAX68]

Well boys, the biggest problem I had with ground was the tail lights, the front lamps should ground by the battery on the radiater support. I think they might ground over on the other end where the voltage regulator should be (on the radiator support behind the drivers side lamps.)

Just for sh**s and giggles, go ahead and turn your lights on and unscrew one of the bolts, if the lights go out completely than you have good ground, and that ain't the problem. But it wouldn't hurt to remove them any way and take some sand paper or a knife and scrape away some rust to make metal to metal contact.

Try your tail lights by turning whatever is giving you problems on (it's easier on stepsides w/the brackets and lamps) and wrap a wire from one of the bolts that holds the lamp to the bracket. Run this wire to a part on the fender or frame that has some good exposed metal. If this is the ground problem, doing this might at least make one side work better than ever, you would pretty much do the same trouble shooting with all the other lamps. I'm sure you can find those similar bolts on a fleetside truck. If this is the case you may just need to then find the original ground from the lamps in the harness and connect it, if not, just make some, by running wires with an o-ring from those lamp bolts to another part on the frame or fender.

I hope I didn't confuse anyone......I just go off sometimes.....

[SWINGSAX68]

P.S.
Halfwaythere,
you had the exact same problem I had, and if the turn lamps did work they were very very slow, right? I have a feeling that it is the tail lamps missing ground that solved worlds of things for me!!!!. My indicators on my dash wouldn't work so I would pound them until they did.....kind of like putting your hand back there. Also, check your blinker fuses.....might be weak. If one little lamp is missing ground, that could mean a whole lot of stuff is not going to work right, just need to keep looking!!!!

[jhow66]

This bulb on my former 72 is the one that supplies light to your shift indicator--the "wire" is really a fiber optic cable--it goes up the column with the wiring harness.
www.geocities.com/jhow66/2-.html