I have re done all my main battery wiring in my 1987 turbo II. I have 2 main power wires from + of battery. One going to starter and the other to the engine bay fuse box. Then from that fuse box it goes to the alternator. I have one ground from battery to starter motor housing. My problem is when I hook up the battery the car is on. Interior lights turn on without key in ignition. How do I fix this?

 

When you say "interior lights" do you mean the idiot cluster lights or the dome and courtesy lights?

I suggest you download the Wiring Diagram section of the factory service manual and compare the main wiring to your work. But it does sound like everything is hooked up correctly.

The engine does have a grounding strap and the battery's ground should also connect directly to the body.

 

If it is the dome lights, those turn on without the ignition, if the doors are open. Maybe the door switches are broken / not mounted.

 

If you open the door with the battery hooked up the lights in the door and the one by the ignition will turn on, and the dome light if the switch is on door, if you shut the door the key hole light will remain on for a while. At least that’s what mine does.

 

sounds like these guys are on top of this. I do however suggest running another ground from the battery to the chassis. I believe the factory wire grounds on the driver's side shock tower near the main frame rail.

 

More importantly, I would suggest checking the battery to body ground and checking for any rust. If there is any rust, remove the bolt, buy a M6x1.00 thread tap (double-check the bolt size first, it may be larger, use with penetrating oil and start it by hand) and clean out the threads, replace or wire-wheel the ground bolt and re-assemble everything with electrolytic grease.