IZAOLDS

I have a 71 cutlass, my headlight on the pass side is dim but not out, this is the second time its gone dim after replacement with a new lamp,and it only happens on that one side any suggestions or ideas fellaz of what this may be?????

MDchanic

Dirty contacts in the plug.

Possibly a loose-fitting spade lug female in the plug.

Remove the plug, use a very small screwdriver or pin to press down on the barbs on the back of each female spade connector in the plug, and pull them out the back (don't lose track of which goes where), give them a good cleaning (Dremel moto-tool with tiny wire brush fitting works great for terminals of all kinds), gently squeeze each connector with a pair of pliers to tighten (check tightness on headlight lugs), then reassemble with vaseline to reduce future corrosion.

- Eric

svnt442

Yeah it's a bad connection. The old bulb should still be good as well.

MDchanic

Good point.

IZAOLDS

thanks guys, yea Ive tossed the old lamp, now gotta tear it down and find that area of the bad connection wish id knwn that the first tear down, I jus thought it was a bad lamp, especially since it work'd fine after the change, but hey this is what you love to do with cars thats of this age, work on em.....

My442

The Packard type 56 connectors are exposed to the elements. The deisgn also allows corrosion to creep up the wires from the connector.

It is cheap insurance to replace the engine harness and forward light harness to cure those issues.

The underhood stuff takes a beating after 40 years.

I suggest M&H for the harnesses.

oldcutlass

It may also be at the connection of the drivers side lamp where the pigtail is. Faulty crimp. OR a corroded wire in between. I'd also check the grounds.

Yellowstatue

X2 on checking the ground connections...

Mingus

Dim is usually a bad ground. My wifes' LeMans was having an intermittent dim headlight. The ground wire was hooked securely, but was corroded under the connector. I cleaned it off and it's been fine since.
Mike

joe_padavano

X2 on all the above. Start with the ground terminal, which is under a screw on the core support behind the headlights. Remove and clean. Next check the terminals in the headlight connectors. The headlight terminals are actually Packard 59 series, which are larger versions of the more common Packard 56 terminals. You can remove the terminals from the plastic connector body with a jeweler's screwdriver or a straightened paper clip, allowing you to properly clean them. Use a dab of dielectric grease when you reinstall them.

TripDeuces

99% of the time an electrical problem can be traced to a bad ground. I'd start by checking the ground wires attached to the radiator core support and move out from there. It would be a good idea to pull the contacts out of the headlight plugs (pigtails) and clean then up also.