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Headlights -GM

Interesting piece of Trivia.

I had a front halogen bulb going dim on the

1990 Silhouette, which has a four bulb front system. (two outers, low beam....two inners high beam).

Replaced the bulbs and started checking things out.

At low beam the two outer lamps come on At high beam the two inner lamps come on (and the outer ones are off).

It's a two wire system... each switch handles V+ to a different set of lamps.

So, I checked three GM cars

1990 Olds Silhouette Mini-Van 1992 Chevy Lumina APV 2002 Chevy Monte Carlo LS

And, (believe it or not), on all cars, the low beam calls for one set of two lamps. The high beam calls only for the other set of two.

otoh my friends 1994 Buick Regal uses a four lamp system and when using high beams all four lamps are lit !!!

Why would GM use two different headlight systems???

To convert this to a 4 light high beam system all I would need to do it jumper hot from the high beams to the low beams using a diode and quick connect coupler. Is this thinking correct ??

Thanks !!!

Reply to
Peter
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Perhaps the headlight capsule can't handle the excess heat, so only two are then lit instead of four. Look at the 97 Grand Prix's, notorious for the plastic headlight lens to literally fall off when driving.

A friend with a 92 Century drove for over a year with his high beams on thinking that his low beam ( which was burned out for a year ) would come on when the highbeams were on, but that wasn't the case.

The same Century had the LH turnsignal lens fall off the back part of the housing. That was probably due to a poor adhesion not heat.

Only two lights on at a time here.

========= Harryface =========

1991 Pontiac Bonneville LE 3800 V6 ( C ), Black/Slate Grey _~_~_~_~277, 300 miles_~_~_ ~_~_
Reply to
Harry Face

Quite possible. It could also be that they didn't design the reflective optics to be used as a high-beam on the low-beam side on some models. In that case, a user-designed conversion _may_ throw the wrong hi-beam pattern (illegal).

Reply to
James C. Reeves

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