I have a 78 cutlass. My headlights were working fine but the last 2 weeks while driving at night of course my headlights would flash on and off every now n then. But now they don't work at all. I checked the fuses and they all are good. Headlights are new. Tailights work parking lights work but turn signals don't. Could someone plz help. Any info will help

 

Where is the dimmer switch? I don't know if they were up on the steering column by 1978 or still on the floor. Regardless, I would check the connections to it and whether it's working correctly. All power to the headlights passes through it, so if it's on the fritz, so will be your headlights.

 

I had a floor switch go bad on me years ago. To test it I removed the plug and jumped across with a cotter pin. Hot wire to one gave me the low beams, hot wire to the other gave me high beams. If you can find the plug as jaunty said this is an easy way to test the switch. John

 

Check the main harness connector at the front. It may have come loose or there may be corrosion on it.

I'm sure the 78 had the headlight dimmer up on the column with the signal switch.

 

Allan is correct. I looked it up just now at the Autozone website, and the dimmer switch for this car is definitely not floor-mounted. It's just an $11 part, so the cost to replace it if it's bad is nothing, but I'm guessing that getting at it is a bit involved as you will have to at least partially disassemble the steering column. If there were ever a time where a factory service manual for this car would come in handy, this is it.

If you don't have one, here's one for just $10 (plus shipping).

http://www.ebay.com/itm/1978-Oldsmob...899559&vxp=mtr


What I'd go for, though, is this:

http://www.ebay.com/itm/1978-OLDSMOB...777b6c&vxp=mtr

It's the factory service manual, which covers mostly from the beltline down, AND the Fisher Body Manual, which covers everything else. Electrical items sometime are covered in the body manual. It pays to have both on hand, and for just $12 (assuming you're the only bidder) and free shipping, you really can't go wrong.

 

Nice find Dan. I second the recommendation.

 

Could also be the circuit breaker in the headlight switch - either you've got a short, or the breaker's bad.

- Eric

 

Sounds like the headlight switch itself to me. It has a built-in circuit breaker for headlights. If there's too much current passing thru, or the CB has gotten weak, it will open and then reclose after it's cooled down a bit.

What type of headlights do you have? Sometimes newer high-powered headlamps will psuh an older or marginal switch over the edge.

Dimmer switch is no real problem to tackle but having the shop book will help, if for nothing else but how to set the preload on the switch and actuator rod. It does require lowering the steering column to get access to the switch attaching screws and wiring plug.

 

Not sure what kind of headlights I have but I pulled the headlight switch out of the dash and I'm getting power out of 2 of the outputs. Is this correct or should I have power coming from all 6 outputs (circuit blades)

 

If you did not change or modify the headlights right before they started flashing, then I suspect the breaker in the headlight switch has weakened. If you actually had a short, the light output would be next to nothing when they did light.
This happened with my old Ford. First an occasional flash, then eventually, they flashed more often. Replaced the light switch and it stopped.

The big red wire comes from the battery and feeds the headlight circuit and should be hot at all times. Light blue should be hot when headlights are on.

The big black / orange strip wire comes off the fuse block and feeds the running light circuit and should be hot at all times. Brown should be hot when running lights are on.

Other terninals are for the dash lights and courtesy light switch.

 

I'm going to test those locations and see what I get. Thx .will keep u posted. hx for the info