I have a '68 442 with column shift. Previous owner installed a gauge pack, hacked up the old wiring harness, and did some odd things. Got a new dash harness, got the old harness out, and I am in the process of planning my installation, testing switches, seeing where things go, and fixing the hack job on some of the extension harnesses.

So as per the title, I have two questions at the moment:

For the simple one one, I am testing the neutral safety/backup light switch that mounts to the column. On the neutral safety prongs, when I sweep the plastic tab through its range of motion, I get continuity twice, presumably in park and N. But on the backup lights prongs, with the same sweep, I don't get continuity anywhere. Is my switch toast on the backup lights circuit or am I missing something?

Now for the more complicated question:
What is the correct way to wire in map light and options (rear defogger and pwr antenna in my case)? Previous owner had disconnected glove box light and radio and used those hots to power the options. He then wired the map light in series with one of them, cut the white wire to the map light and reused it as a ground so that the light only operates when the switch is moved.

Sorry I wrote y'all a book.

 

Sounds like the switch is bad. You should see continuity on the backup light terminals between the PARK and NEUTRAL positions.

Typically the factory provided a single terminal connector for these feeds. The accessory had a "Y" connector that plugged into the feed and provided another tap for additional accessories to be daisy-chained.

 

Thanks as always Joe!

Follow up questions:

Where would the lead for the accessories connect to the fuse panel?

Did a bit of research: does the map light need a courtesy light harness to function properly, if not, where does it connect to the the dash harness? What happens to the white wire? Single spade connector to ... ? second terminal on passenger door jamb button?

 

Which accessories? The orange wire that feeds power to the clock, cigarette lighter, and map/courtesy lights is built into every dash harness already. The courtesy lamp harness, if so equipped, plugs into one of the several connectors that are spliced into this orange wire in the dash harness. The lower RH corner of the wiring diagram (fig 12-2) in the CSM shows this. Other accessories plugged into the accessory power feeds in the front face of the fuse panel. There are four terminals running down the center of the panel. Some are hot all the time, some are switched, depending on the application.

This is actually a photo of a GTO panel, but the Olds is the same. Note that this one doesn't have all the feed locations populated. Also note that the recesses have different configurations for ridges on the male mating connector, to prevent an accessory that needs switched power from being plugged into a terminal that is full-time power.





RPO U29 was Lamps, Instrument Panel Courtesy and Map. They were installed as a set, so yes, you would need the entire harness for this to be plug-and-play.

The white wire is the ground. Yes, it goes to both door jamb switches (map light comes on with the courtesy lights). The switch on the map light provides a separate ground to just turn on the map light.

If you are trying to install the map light without the courtesy lights, you can simply connect the orange wire from the light to the feed in the dash harness and be sure the ground to the switch on the light is in place. The map light will function from the switch but not the door jamb switches. Of course, you could run the white wire to the jamb switches also if you wanted to do that.

 

Thanks again Joe, I'm getting close!

In my instance this would be power antenna and rear defrost. So these would take a hot from the "acc" slot on the front of the panel and be daisy chained together under the center of the dash?

So, the orange wires in the main harness, I have two left over: A male right by the ignition, and a female tethered to the white passenger ignition button wire. I thought the male went to the back of the tach for its lights, and the female was just the glovebox light but now I assume is for the courtesy lamp harness as well, correct?

This might explain some of the confusion, the only part of my courtesy light harness that is left over is the map light, which has been sliced and diced. I wonder if the rest of the harness is wherever the AC ducts are...