Brown and white stripe, goes up behind the fuse box. It has power when I put the test light on it. Anyone know what it’s for?

 

That looks like the same connector that is used on the mirror maplight.

The map light has power all the time and is controlled by the switch on the mirror, so its wire would have continuous power. The wire runs up along the A-pillar then across the top of the windshield to the mirror mount, down the mirror arm, and plugs into the receptacle on top of the mirror.

 

This isn’t long enough unless there’s a another wire to plug into. This is from fuse box hanging down towards the high beam switch. My pic went sideways

 

Reminds me of the wire going to the door switch for interior lights, dome light and some have under corners of dash lights. Does your dome light work? If not this wire may be the one which provides the ground to make the dome light work.

 

My vote is for the parking brake alarm. No bells or whistles, just a light on the dash.

 

The mirror also has it's own wire and (from memory from along time ago) connects to the power wire somewhere along the window frame.

 

I wonder if it makes any difference what year/model car?

 

Brown single white stripe = 10 Ohm resistance wire
Brown double white stripe = Park

1971 CSM

 

May be the under dash lights, they don’t work, but my roof and side lights work. My car is a 70 supreme

 

Have you considered reading the wiring diagram in the CSM?

 

That wire in the image looks more tan than brown. For a 1971 CS the parking brake switch is tan double white stripe. This may or may not be the same for the 1970 CS, but the 1970 CSM would demonstrate the appropriately color-coded wire for the parking brake switch.

 

1971 Original GM Oldsmobile CSM Wiring Diagram A Body "V-8"

Use at your own discretion. NOTE: This is the 1971 wiring diagram.

 

Thanks, I appreciate all the help, it does look more tan than brown

 

If I were to guess, I'd guess @ the parking brake dash lamp switch, also. It's easy enough to see if there is a wire in the parking brake switch. It's located at the top of the parking brake pedal bracket IIRC. If there isn't a wire in the parking brake switch already, there certainly should be.

 

Note the difference in the connectors between the mirror map lamp lead and the parking brake lead wire. This is from the 1970 PIM. That wire should plug into the parking brake lamp lead. Plug it in, push the parking brake in, turn the IGN and test it. It should light up. You can begin troubleshooting your other lighting issues with that diagram link I provided, but your best source is to buy the 1970 CSM which comes with color-coded wiring diagrams and is much easier to read, beside the plethora of information contained in the CSM.

 

^^^^ My hero.

 

Occasionally I'll can sneak in a winner.

 

Looks like it, now I have to see where to plug it in