Need backup bulbs for my 71 Cutlass. Autozone and Advance Auto, the two local parts houses both list a 90 bulb for the car. I bought a couple but the have two terminals on the base. The socket has a single wire picking up ground from the case. Does anyone know the correct bulb number for this application?

 

Should be an 1156, no? That's the standard bulb for 12v cars for about 40 years.

I think the 90 was the special bulb for the rear seat lights in the convertibles.

- Eric

 

X 2 on what Eric said

dsolomon - it's right in the owners manual under the section on Lamp Specifications.
External Lamps - Back up (qty 2) 1156

These have only got one terminal at the bottom of the bulb. The 1157's are the ones with 2 terminals - they have to provide running lights + turn/brake indications.

 

1156 was the single - 1157 was the double!

 

And 90, if my memory is correct (I am not looking it up right now), has the same base size, double bottom contacts, a smaller bulb, and a single filament, with the filament connected to both of the bottom contacts, and the base not connected to anything, as used in the convertible pillar lights... A real oddball.
As I said in a different post, "Why ask why?"

- Eric

 

Awesome! I have several in the Chevelle parts bin. I guess the standard for chevy's is the standard for Olds. I read that the owners manual lists the bulbs but mine is tough to get to. When I do a resto I pull parts and load into bins. The manual is litterally the first thing to come out and bin #1 is at the bottom of the pile. Thanks for all the help.

Now for a quick rant... God I hate repop parts. One of my backup lamp housings had a corroded spring in the pigtail. I picked up a repop one at Carlisle this fall. Just went to install the bulb and it flops around in the socket like a fish. I am convinced that it will be an issue later. It just amazes me how such crap can be produced. Its like they take a shot at reverse engineering and when they find its out its not close they say "awh thats good enough". Guess I need to search for a used one.

Thanks again guys!

 

Yep, that's what I say. 90% of all the repop crap I have dealt with is "modify to fit".
Cannot even get a starter heat shield (small steel plate with two holes) to have the holes drilled in the right spot.....

 

The 1156, 1157, and (later on) 194 were used in the exterior lighting of pretty much every car, American or European, from the fifties through the eighties.

Light bulbs are listed in the owner's manual, the Chassis Service Manual, and any Motor or Chilton manual you might come across.

- Eric