Hello everyone, first time poster! I'm the proud new owner of a 1969 Oldsmobile 98 LS (4 door hardtop) 455/auto. What an awesome car, well taken care of and had every option except for the rear seat centre speaker, and disk brakes! Pretty cool having factory A/C and cruise in 69!

Anyways. I've been working on getting all the lights freshened up and shining brightly. I've made good progress with the exterior lighting.

My main problem is to do with the courtesy lights. I don't know if all other 69 old's are the same, but my car's courtesy lights include 2 bulbs under the dash, 1 bulb on the dash above the radio that also contains the master switch, 2 bulbs on the pillars above the package tray, and 2 bulbs per door.

I have only replaced the two bulbs under the dash board so far, and they worked perfectly for a few days. Then one day i went for a drive, and attempted to turn on the lights using the master switch. Almost instantly, the driver side bulb burnt out and filled with white smoke. The passenger side continued to work and the fuse had surprisingly not blown.

I shut off the surviving light, then attempted to replace the burnt out bulb with a new one. The new bulb turned on instantly without me turning the switch on. My driver door switch does not work right now by the way, so it has no affect on the function. I have checked and they are all plugged in, so i don't think they're the problem.

So anyways, after i installed the driver side bulb which now won't shut off, i attempted to turn on the master switch, and they both come on very dimly, and then it blows the courtesy fuse.

So i replaced the fuse and took the bulb out. Now i can only use my passenger side bulb, and possibly all the rest i have yet to replace, accept the driver side bulb. Anybody ever seen this particular problem before? I feel like its something simple like a bare wire shorting out, but i don't understand why it blows the fuse and why the other bulb is not affected if the driver side bulb is removed. Something to do with the switch? Any particular wires i should check out first?

Sorry about the long post, any advice is greatly appreciated! I'm not the best wiring investigator haha.

Weston

P.S. heres a photo of the old beast. Needs lots of work, but its a damn good start.

 

Weston, you need the 1969 Oldsmobile factory Chassis Service Manual and the 1969 GM Fisher Body Manual. Get an original print copy; the reprints, CD-Rs and online PDFs have issues.

In addition to full color wiring diagrams the CSM and FBM will help you or anyone you hire to service the car do it properly.

First thing is make sure you're using the correct # bulbs in the underdash courtesy lights. I think 69 used a double contact bulb.

Also look into replacing that driver's door switch. It is a 3 terminal switch; other doors are 2. The switches complete the dome and courtesy lamp ground circuits and if one isn't working it can make plenty of problems.

With battery disconnected try spraying some WD40 or electrical contact cleaner into the pin switches and working them in and out a few times. If they're grunged up internally sometimes cleaning them helps.

Dare I say that car looks a little sinister parked in that alley?

 

^^^^^ X2, Confirm that ALL of the bulbs are correct first ^^^^^^^^

Great car, post pics when you can.

 

I have a 66 98 and Starfire. Yours May be different, but here’s what I can contribute. Yes, definitely get the correct bulb type and wattage in each bulb location so you know the bulbs aren’t your problem.

If yours is like mine there is a fuse between the battery and courtesy lights. Someone before you may have replaced it with a higher amperage fuse which is not blowing when it should and is, instead, blowing bulbs. Or the bulb housings could have corrosion or bad grounds. My system uses orange and white wires as a pair, perhaps yours does too.

The weakest part of the system: the door jamb switches physically move the courtesy light wires every time you open and close the doors. So they fray over time in the voids behind the kick panels and can ground out to the battery if the insulation has worn through or worn off.

To diagnose, look at the most used door switch first — aka the driver’s door. Then move to front passenger door switch, then onto the rears.

Hope this helps. These systems work well, but wear over time. As do we all

Chris