headlight problem

[PNutty]

[list=]my headlights shut off randomly while I'm driving. Sometimes for 30 seconds, sometimes for 5 minutes. I've already replaced the bulbs and the plugs, one of which way burned up, and checked the fuses and relays. Battery check at the local pep boys turned up normal. Had anybody had this issue before? [/list]

[AWCougar]

sounds like a swith is shorting across... do you have the auto sensor headlights? if so do they turn on manually or no still?

[The Roadie]

Do the high beams work when the lows go out? Assuming it's a problem with BOTH low beams only at the same time.

It's almost certainly (due to history) the solid state relay used for the low beams. How did you "check" it? A visual check of a solid state component won't tell you much if it's internally flaky.

Interchange the low beam relay with the fan clutch relay right next door. They're the only two black small case relays in the front fuse block.

[PNutty]

Thanks Roadie. Ill try that. The high beams work fine and I still have the same problem when I switch it to manual. My all powerful relay test is holding it up to my ear and shaking it. Unfortunately I never know if my solution worked until it happens again.

[MrSmithsTB]

If the relay is failing, it will shut down when it gets too hot and vice versa when it cools down....I think. Roadie is all know, I would trust his suggestions.

Sent from the strip club

[WaltV]

Seen tons of bad 'headlamp driver modules'/solid state relays. Will be listed as HDM in the fuse block legend. Throws a lot of people because there's a conventional relay for the high beams. Its called Headlamp - Hi.

[Conner299]

Talk about good/bad timing, for this thread. I just had the same thing happen Friday, on my way in to work. Would anybody happen to have a part #, for this relay, or is it something the parts stores will readily have on hand.

[The Roadie]

Would anybody happen to have a part #, for this relay,

Yes. On GMTN or trailvoy. Posting part numbers here for normal and common failure items is not part of our self-sufficiency gig, ya know? Temporarily, you can swap in the identical one from the fan clutch.

or is it something the parts stores will readily have on hand.

Yes. And Rockauto lists many of the aftermarket part numbers in case the local parts store jockeys are as useless as usual and you have to spoon feed them.

Did anybody really expect me to answer otherwise?

[The Roadie]

Oh, buy two. Then you'll have a spare.

[Conner299]

Yes. On GMTN or trailvoy. Posting part numbers here for normal and common failure items is not part of our self-sufficiency gig, ya know? Temporarily, you can swap in the identical one from the fan clutch.

GEEEZ... How could I have been soooo stupid? I guess since you offered up actual advice on such a routine maintenance procedure, I must've thought it wasn't so routine. Hell, I'm starting to wonder why you even actually offered up advice, instead of telling the OP to go be more self sufficient.

[DirtyBacon04]

The OP was busy unpacking his seabags from a vacation in Afghani-land, and Roadie knew this. You're mistake is questioning the Roadie. I assure you there is a method to his madness. I'll be sure to pass on the message to the OP, though.

[Conner299]

The OP was busy unpacking his seabags from a vacation in Afghani-land, and Roadie knew this. You're mistake is questioning the Roadie. I assure you there is a method to his madness. I'll be sure to pass on the message to the OP, though.

You're right, my mistake. I'll be sure to respect the double standard, from now on.

[The Roadie]

I don't know what it is about part number questions that bothers me more. Partially it's that the question has been answered a hundred times on the three forums I've been on for nine years. So the repetition doesn't bother each new person with the problem, because it's all new to them. But it bothers me, and I'm usually not shy about advising a search. How to use ones computer or smart phone to get the answer is a required life skill nowadays, and (as a Dad and old fart) I prefer to encourage people to fish instead of giving them the fish. Yes, tough love and double standard.

That said, part number questions can be an indicator of excessive nervousness and scaredy-cat caution, and that's a definite hot button for me. (Remember the cranky old fart status?) Bad traits to display on a dangerous trail ride, and a good thing to work on overcoming. I see it all the times in noobs, and want to encourage them to grow as well. Yes, I know you're not that kind of noob, but I also write for the unseen future audience that lurks and finds posts like this in years to come. Often a thread is seen by 10-20 times as many lurkers and robots than active members.

I've learned a secret that escapes some folks who always want the cheat codes to life: You can buy parts at the parts stores without walking in knowing the number. In this case you can even bring in a sample to compare. A sample that also has the OEM part number printed on it! If their data base is so lame that they can't come up with a match, they're not a worthy store. Go down the street to a better one. If you're willing to use the fan clutch solid state relay as a swap for a while, and can take the time for mail order, Rockauto has a wonderous data base that lists most (not always all) aftermarket alternatives.

I mock many stupid and unhelpful parts store clerks as being failed mechanics, but that's exaggeration. Unless they're total stoned slackers, they know they succeed only by selling parts. The good ones look things up with skill and speed, and offer you the choices from stock and can look up what's their sister stores have if they've run out. If you know the part number, you might shave ten seconds off the search time, but they may not be able to offer alternatives. Knowing that the fan clutch relay is the same (a tidbit I *did* throw out there) can save you a trip in case they have a lame data base that claims the low and high beam relays are the same, which we all should know isn't true.