Daytime Running Lights non-functional

scottq60 · November 28, 2006

Bought my dad's CHERRY 96 GMC Sierra 4x4 SWB (64k one-owner miles) - He had a "diode" replaced once under warranty but it died again and the DRL's don't work. Is this something I can fix myself (fairly mechanically inclined) and if so, what do I need to do to fix it?

Thanks!

Scott

GM-Tech · November 28, 2006

There are a lot of components involved here and if anyone here can tell you what you need to do to fix it without ANY diagnostic information, they're a better man that I am.

scottq60 · November 28, 2006

There are a lot of components involved here and if anyone here can tell you what you need to do to fix it without ANY diagnostic information, they're a better man that I am.

<{POST_SNAPBACK}>

Sorry I don't have more diagnostic information. I bought it from my Dad and all he told me is that a diode was replaced under warranty and that fixed it for a little while.

I guess my question should be is this a common issue with these trucks, and if it is, what is the most likely cause?

I've seen MANY GM products with at least one DRL not working...probably just a burnt bulb in those cases.

GM-Tech · November 28, 2006

There is no "most likely" or "common" issue on these that I'm aware of. We don't see these failed very often at all. Sure, diodes fail as does the DRL module. I don't like to just guess and tell you to replace something that may not be the problem. Unfortunately, I don't have access to a schematic for a '96, so I'm not able to tell you where to check.

As far as the ones with one DRL out... You're probably talking about the new body style Silverados. Those are bulb/socket issues and are not even close to working like your '96.

scottq60 · November 29, 2006

There is no "most likely" or "common" issue on these that I'm aware of. We don't see these failed very often at all. Sure, diodes fail as does the DRL module. I don't like to just guess and tell you to replace something that may not be the problem. Unfortunately, I don't have access to a schematic for a '96, so I'm not able to tell you where to check.

As far as the ones with one DRL out... You're probably talking about the new body style Silverados. Those are bulb/socket issues and are not even close to working like your '96.

<{POST_SNAPBACK}>

Thanks for the reply!

I had the truck "state-inspected" yesterday so I could tag it here in Md. It failed the inspection due to "cracked serpentine belt" (this is BS...cracks are common and don't mean belt failure is imminent...at least that's what I've been told). The inspector also said I need to replace the idler arm and the brakes have a shudder sometimes, so I have to replace every rotor/drum/pad/shoe until the "shudder" is gone. I dropped $457 at Advance in parts last night.

Funny thing...the inspector said NOTHING about the DRLs not working. So...I guess they aren't required to work to pass a state safety inspection. He did, however, ding me for the 3rd brake light on my camper shell not being connected and said it MUST be working since it blocks the factory 3rd brake lamp on the back of the cab.

Personally, I think the garage where the inspection was performed is just trying to stick me because I did all the necessary repairs on my 99 Taurus to get it to pass their inspection. I believe they thought I'd just go ahead and tell them to fix everything. WRONG! It's like I told them..."if I can fix it myself, I will...if NOT, then I'll let them fix it!" I think they were offended. Why should I pay a garage $70/hr. to do things I can do myself? The Taurus only needed driver side inner/outer tie rods, tires and an alignment. I saved HUNDREDS doing the repairs myself and buying my tires from "a warehouse club".

GM-Tech · November 29, 2006

Wow, sounds like your state inspection is pretty tough. What the heck do they care about a serpentine belt? Wouldn't seem to be a safety item like the DRLs.

We used to have both safety and emission inspections down here in Florida, but they were eliminated many years ago. No inspections of any kind now.

scottq60 · November 29, 2006

Wow, sounds like your state inspection is pretty tough. What the heck do they care about a serpentine belt? Wouldn't seem to be a safety item like the DRLs.

We used to have both safety and emission inspections down here in Florida, but they were eliminated many years ago. No inspections of any kind now.

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There's a column on the inspection form that includes (power steering). The inspector wrote "belt" to the right of power steering and x'd the FAIL column. Like I said, I think they're just trying to "get back at me" for not writing them a blank check for needed repairs on the Taurus. Maybe they thought I'd roll over on the truck too...I wasn't about to give them the satisfaction. If worse comes to worse, I'll pay a DIFFERENT garage to fix the things I can't fix myself, then take it back to them for the re-inspection. After this truck passes, I won't be going back to them. I probably should have learned my lesson with the Taurus, but I've been using them for 12 years now (off and on) and don't really know of a "state inspection station" in the area that I'd trust any more.

GM-Tech · November 29, 2006

Maybe this TSB that says cracking is not necessarily a bad thing will help you with them? Then again, they may not care or appreciate being shown that they're wrong...

Subject: Information on Serpentine Belt Wear #04-06-01-013 - (04/29/2004)

Models: 2004 and Prior Passenger Cars and Trucks

2003-2004 and Prior HUMMER H2

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All current GM vehicles designed and manufactured in North America were assembled with serpentine belts that are made with an EPDM material and should last the life of the vehicle. It is extremely rare to observe any cracks in EPDM belts and it is not expected that they will require maintenance before 10 years or 240,000 km (150,000 mi) of use.

Older style belts, which were manufactured with a chloroprene compound, may exhibit cracks depending on age. However, the onset of cracking typically signals that the belt is only about halfway through its usable life.

A good rule of thumb for chloroprene-based belts is that if cracks are observed 3 mm (1/8 in) apart, ALL AROUND THE BELT, the belt may be reaching the end of its serviceable life and should be considered a candidate for changing. Small cracks spaced at greater intervals should not be considered as indicative that the belt needs changing.

Any belt that exhibits chunking should be replaced.

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.

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