I scanned back over several postings, but didn't see anything about this. Have a 2002 L-200 that has an interesting condition -- during the nighttime hours, when the A/C compressor starts the headlights blink almost totally out. Probably happens during the daytime too, but hard to see that. Checked the battery terminals, and they are clean and tight ... suggestions?
OK -- Ran the vehicle down to AutoZone, and had them run diagnostic on the alternator ... result? Alternator is fine. Thanks for the suggestion, but that's apparently not it.... any other ideas???
Weak battery. Will probably fail on you early Sunday morning when no tow is available. It will be raining. That is the way these things work.
Took your advice -- back down to AutoZone, pulled the battery and had them run a diagnostic/load test. Battery checks fine, with no indication of loss in power or bad connection. Put it back in, and checked for load with the key off. Nothing there either. Darn it - I know there's something amiss, but I just can't find it. I appreciate all the suggestions cuz I'm not well versed on these new cars, but I've still got this dammed dimming problem. Additional suggestions welcomed, and I'll try to keep digging at this end too......
pretty much normal. i first noticed it on my L300 in dec. 01. now at 45,000 miles, no problems and no worse. a friend of mine works for saturn, sees it all the time.
There is a service bulletin 04-08-42-001 about this, apparently GM considers this a normal condition: "Information on Intermittent Dimming (Flickering) of Headlamps and/or Instrument Panel Lighting -- Normal Characteristic/No Service Required 2000-2004 Saturn L-Series Vehicles The purpose of this bulletin is to inform Saturn Retailers of normal headlamp and instrument panel illumination characteristics. Customers may comment on sporadic dimming (flickering) of the headlamps and/or instrument cluster illumination. The flickering may occur intermittently as a result of transient current loads on the electrical system during normal vehicle operation; however, at no time do the headlamps turn completely off. This is considered a normal operating characteristic. No service is required for this condition."
Guess this also explains the flicker I observed when I flash my high beams. Now that the switching of electrical circuits is done largely by semiconductors rather than by relays, it's a new ball game. A relay can take a very large overload while transistors can not without being damaged. Even a fuse can not properly protect a semiconductor device. Almost always a semiconductor will give its life to protect the fuse unless some other protection scheme is designed in. This is done by some form of active current sensing in the drive module. If an overcurrent is detected, whether a short circuit or a momentary overload, the load is turned off for a period of time to protect the transistor. The fuse is now only used for catastrophic protection and protect against a fire. Trouble is sometimes even a glitch on an unrelated circuit can cause the overcurrent trip-out. In the case of the OP, check that the diode that clamps the transient voltage from the AC clutch is both installed and good. On the L series, this is located in the under hood fuse panel and is labeled 'diode' in the key. I have noted on my car too, that the electrical regulation from the alternator is ok but not great in response to a rpm or electrical load change. It seems to take about a quarter second after applying a load until the voltage stabilizes again. This can cause some glitches but this does minimize the load on the engine as it accelerates ) Bob Oppenheimer Electrical Engineer '01 lw300 _________________ | There is a service bulletin 04-08-42-001 about this, apparently GM considers | this a normal condition: | | "Information on Intermittent Dimming (Flickering) of Headlamps and/or | Instrument Panel Lighting -- Normal Characteristic/No Service Required | 2000-2004 Saturn L-Series Vehicles | | The purpose of this bulletin is to inform Saturn Retailers of normal | headlamp and instrument panel illumination characteristics. | | Customers may comment on sporadic dimming (flickering) of the headlamps | and/or instrument cluster illumination. The flickering may occur | intermittently as a result of transient current loads on the electrical | system during normal vehicle operation; however, at no time do the headlamps | turn completely off. This is considered a normal operating characteristic. | | No service is required for this condition." | |
What kind of crap is this? How can this be a normal condition. What they are saying is that they can't come up with an explanation. How SAD!
Speaking as an electrical engineer, there is a difference between what can be done technically and what the bean counters will allow to be done. Even to put out any technical information to fix a problem sometimes makes lawsuit fodder. From the corporate point of view, it is just better to ignore problems until there is a class action suit. Sad, eh? Oppie _________________ | What kind of crap | | | is this? How can this be a normal condition. What they are saying is | that they can't come up with an explanation. How SAD! |
And then I noticed on the LW300 when I flash the high beams, the yellow led for the automatic trans shift indicator blinks out for a moment. The radio has also been getting static lately. Common point may be a loose ground strap? I ordered the factory service manual finally. Next step is to get a subscription to Alldata and a decent code reader (I love to play). Cheers
