Hello - my 73 seatbelt warning light and the right turn signal lights illuminate and remain on when I select my headlight switch on. Both parking and headlight functions cause this issue. My turn signals operate correctly but the indicator remains illuminated. My seatbelt light doesn’t function at all until I use the headlight switch. There is never a warning buzzer. 

Any ideas on where to start?  

ed

That's a weird one! I would have to think about a bad ground behind the dash somewhere...

Weird for sure! I have an aftermarket shop manual that has nice wiring diagrams and I was trying to see where that circuit might come together but no luck so far. At some point the dash will probably gave to come down for some other issues as well (lighting related). Thanks for the reply!

I have the wiring diagrams for '68-'82 Corvettes on my web page, you can view and/or download them from there if you wish.

Thanks Joel. I've downloaded them. I do have a shop manual but yours appear to be a little easier to follow. I guess I have my winter project planned if I need to pull the dash apart. Ugh.

What were you "tinkering" with before this happened?  😉

Well, nothing yet. The car was my fathers until he passed away. He had new engine and front lighting wiring harness installed but I didn't think that was the cause. I don't really know the car's history. There are a few other electrical issues - the aftermarket radio doesn't get power, the brake light doesn't work with the parking brake on and so on. 

Update - My right signal light no longer illuminates with the headlights on. Apparently, had something to do with a bad connection up front and my front right marker light was out. In looking at the wiring diagram, the brake warning control (tan), connected to the parking brake switch and the brake warning sensor, is close to the tan to brown that goes to the left headlight. However, I'm really not sure what I'm looking at when looking at the "bar" where these wires connect. Looking at the diagrams, can anyone advise what it is and if it would be possible my brake light is shorting to the headlight at that location?

In your second pic, the long "bar" is a connector. It appears to be the pass-thru connector at the firewall, under the brake booster/master cylinder. That particular connector has caused many problems on a lot of cars. It is the main connector for the forward wiring harness, and the fuse box. Sometimes, just un-plugging and plugging it back in will fix a loose connection. In order to disconnect that connector, you must first remove the bolt holding the two components(forward harness/fuse box) together. It can get corroded over time, or even just be loose.

OK! Thank you. I have looked at it and it has the new engine harness attached so maybe there's an issue at the connection.