FREQUENT HEADLIGHT FAILURE on 62 LeSabre

[Guest COMPACTBC]

The headlights (low beam)burn out after only a few months of use. Anyone know what might be causing this to happen?

[Guest 70 Electra]

If you're using original (i.e. "old") sealed beams, the problem may be the lamps themselves. I can't tell you what I've spent on NOS T3 bulbs, only to watch them fry themselves into oblivion after anywhere from 1 minute to 6 months of service.

I've been told the "airtight" seal between the lens and reflector is sealed with a brittle sealer. It cracks from age and handling. Once this happens, there is no long the necessary vacuum condition inside the lamp. Moisture from the outside air enters the lamp, and it's soon all over for the T3.

Another possibility would be if the voltage regulator is allowing the generator to put out too much charge and this is prematurely buring out lamps.

[NTX5467]

As a point of interest, have you checked the voltage at the bulb with a voltmeter and the resistance at the connection joins in the wiring harness (really two different issues in some respects). Higher than normal voltage (like 14+ volts instead of 12.7 volts) might be an issue, but it would also affect other bulbs in the vehicle too.

If there are some degraded connections/terminals or gunked-up connections, that could result in high resistance and lower voltage to the bulb. The lights could be a little dim too. The bulkhead connection on the firewall should also be inspected too.

Other thing would be vibration. Maybe the hold down springs or the retaining ring around the edge of the lamp are loose? A side issue might be the quality of the sealed beams that are being built today not being quite what they were in earlier times.

Just some thoughts,

NTX5467

[Mrbuick714]

Do you have a Delco Voltage regulator? Some "Dimestore" regulators do not have temperature compensation ability,and the voltage climbs as they get hot. Delco units can give trouble if the upper points go bad. Check Delco units when they are up to operating temperature and you have a good battery that is fully charged. Ralph Crisp

[Dave@Moon]

I think NTX's point about vibration is the most likely suspect. If the voltage were a problem (and it should still be checked just to be sure) then <span style="font-style: italic">all</span> of the other bulbs would be burning out just as fast. In fact you'd probably see the problem first in the (much more frequently used) brake light bulbs.

Check your headlight buckets and retainer rings for weak spring retainer points as well as the springs themselves. Also the front apron may be being jarred by a loose fender or bumper mount and/or some missing rubber bits. Good luck!