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Help diagnosing front signal and marker lights, and low beams

I have a 2004 buick lesabre that last year had the steering wheel harness replaced (left blinker issues and then just total car dying while driving). This year, the right signal light blew out, along with the low beam light. When I replaced them, the low beam light was very faint, and the signal light worked (till the next morning for the low beam light and till I closed the hood). So fiddled with the signal light, it works- but now the right signal blinker works but not the marker light and still can not get the low beam to work again. Just wondering if anyone has any thoughts for me to figure out what is going on.

Sounds like a bad ground.

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Is it the actual low beam headlight that is dim? Or the little light on the dashboard is dim, the one indicating the headlights are on low?

the low beam headlight was actually dim, but now there is nothing. the green turn signal light stays lit but then eventually go off, only to turn on again. My dashboard lights have been goofy for year- light then dim, then light and I lost my mileage light (seems like for good now after 193000 miles).

if it was a bad ground as NYBo mentioned- how would I or could I test that (not much of an electrician though), best to take it to the garage?

Number 4 in the diagram, G103 is the ground location for the front turn signals and low beam lights.

A shop would probably measure the voltage at the headlight bulb connector. If it measured considerably less than battery voltage, the reason most likely would either be

  • a high resistance in the power lead between the battery and the bulb, or
  • a high resistance from the bulb ground to the chassis

They’d then connect a jumper wire from the bulb ground to the chassis. If the bulb brightened back to normal, they’d know it was the second of the two, a ground problem.

Since you say you don’t have much experience with electrical diagnosis, yes, going to a shop is probably the better choice.

thanks this is helpful

I might end up there anyway but thanks to you all I have a better understanding!

Best of luck :slight_smile:

Usually you can remove the ground screw and clean up the terminal lug and any rust on the car chassis and put it back together and your problem will be fixed.

thank you - let all you know how it turns out but won’t be getting to it till next weekend.

Or easy enough just to add another ground or a temporary ground wire to see if that does it. A ground wire doesn’t care how many there are.


[quote=“Bing, post:12, topic:96000, full:true”]
Or easy enough just to add another ground or a temporary ground wire to see if that does it. A ground wire doesn’t care how many there are.
[/quote]That’s what I did when a headlight ground failed in my '05 Pacifica. The factory grounding point was buried under a mass of wiring, so I just spliced in a new ground. The headlight never knew the difference.

Well after looking at it again and just playing around all lights turned on, but looks like the ulti function switch in the stearing wheel is causing issues - it’s sticking at times and make for wonky light (as sometimes high beems work, others they don’t, same with sidemarkers and blinkers). oh well the core support for the radiator is rusting through too, they didn’t want to give it a yr inspection sticker- looks like I am looking for a new car soon anyway.
Thanks to you and everyone else who replied with helpful answers.

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The car is not worth welding in a new core support . . . ?!

Besides that, is the car in miserable condition?

well it’s 12yrs old, and where I live salt eats all underneath and I have over 200,000 miles on it. I don’t weld. I have already replaced the air conditioner compressor and condenser and the air compressor went again this summer. I am not great with electrical repair. I just think for my level of ablity it’s time to hang it up.

200k and serious rust on a Lesabre? I agree, good time to start looking for a replacement car.

Thanks, I feel so much better for hearing that. After this year getting new tires, muffler, all new brakes and rotors and all new hub assemblies on the car it was a hard choice- fix or not to fix, but with the extensive rust and and the “little” things such as wonky lights I need to give her up.

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