I haven't posted in a long time, and my apologies that I am always reaching out for help. Just trying to keep my 2003 Blazer 4x4 4-door (with 112,000 miles) operating smoothly. I'm having a couple separate (or related?) issues with her lately:

1. Flickering headlights, dashboard lights, radio lights, overhead light. This is noticeable, especially the headlights at night. I had my alternator replaced in 2007, but not discounting that it could be the alternator. I haven't checked the ground or voltage yet either. To that end, it may (or may not) be related, but my Blazer idles at 500 rpm, sometimes less.

2. Bizarre, consistent, clunking sound coming from the general area on the passenger side near the dashboard/windshield. I've removed everything from my Blazer (CD jewel cases, items in the glove box, any loose items, scoured the interior for loose change) and it still made the clunking noise. Any ideas?

Another thing, could 1 and 2 be related?

 

For the flickering I'd start by checking grounds - battery to engine, body to engine, ground under the fuse box under the hood. POS to starter as well, make sure the connections are clean & tight.

The clunking sound sounds like a hood hinge issue. Been there & wrecked my brains over that "clunking in the dash". Try folding up a small rag & putting it under the hood by the windshield & hinge on the offending side.
If the 'heavy plastic on metal kind of sound goes away go to a GM dealership or Rockauto.com (look up the monthly code for a discount in here) & get the conical washers.... That's what I'd do for starters anyway.

 

+1 to everything rotti said

 

Like rotti said, check your grounds for the flickering. My blazer was doing this a while back and I swore it was the alternator. Took off my grounds, sanded them down and reinstalled them. I haven't had the problem since.

 

<---- That was me this morning when the clunking noise went away! I'm really happy that I'm closer to a resolution to that issue because it was driving me absolutely insane.

Where can I find the grounds? Please no laughter from the peanut gallery. Are they under the hood or the fuse box?

 

The grounds are all over just find any wire that is attached to any part of the body or frame with a screw or bolt. Once you find them check and make sure they are tight and also follow the wires and check for damage and ensure they are tight or connected on the other end as well. There are a couple around the headlights, a few come of your negative battery terminal, and possibly some randoms on the fender wells and fire wall. Hope this helps!!

 

There is also a ground array on top of the frame at the rear on the DS.
What was the cause of the clunking btw?