Hello all....I've had my SA for about a year now. I'm just curious if anyone has experienced this issue. In order for me to use my radio, antenna, or rear defrost my lights have to be on (park or headlight doesn't matter). I haven't investigatedone the issue, just thought maybe someone had a clue.

Thanx

Shane

 

Weird one Shane. First thing I would do is get the 79 OE Electric Wiring Manual. There may be a .pdf downloadable version thru a member here, or thru ebay on occasion. Expect to pay about $15.
The good news is that most of the wiring under the dash (and in the center console) is very straight-forward and easy to get at. The center console electrics are all on a single SUB harness that connects near the rear of the instrument cluster. I would start by removing the center console radio panel and the shift plate covers and check the connections at the 3 rocker switches there.
Obviously a common power lead that runs the lights then on to the switches may be the source. The light switches all are connected thru several harnesses that are under the Steering wheel column. Should be 4 . Check for correct plugging there too.

The manual makes the interconnection paths much clearer!

'Luck!
Stu Aull
80GS
Alaska

 

I'd check for good grounds if you end up digging into the wiring. Over time they can deteriorate and cause all sorts of weird symptoms and problems. If you've only had the car for a year, you could be experiencing a previous owners attempt at fixing or modifying something.

 

+1 on grounds. There is a ground wire straight up under the dash above the steering column.
You have to be upsidedown under the pedals to see it. Make sure its a good connection.

It could also be the ignition switch (not the lock cylinder) thats attached to the back of the
ignition lock. When it starts to have issues it has weird affects like this. I had to replace/rebuild
mine a few times over the years if I remember right.