[Bowtied]

Hi guys,

I had made a thread previously about my truck lights/dash/accessory dash lights/etc. dimming randomly.

Well the problem has gotten worse and also started acting up in different ways, for example previously the lights used to "tick" after i'd warm the vehicle up and put it in drive for the first time of the day, now, when i come to a stop somewhat quickly the truck is hesitating, idle is surging (almost trying to stall) while lights dim and act like they are draining.

Also, battery checks out at 12.3 to 12.5v when the engine is cold, off, and not started since the previous night.

The lights in the dash also dim when i roll the windows up which i had previously posted about.
When I turn the truck off after arriving in my driveway the lights immediatley dim somewhat, about 25% to 33% of total light output.

Im thinking more and more that now that the problem is getting worse and worse this must be a loose ground on the battery, or other related area? Starter?

I am not extremely familiar with the locations on this engine and was hoping someone could tell me locations of the most common grounds for this truck that i can inspect easy and right off the bat.

I am going to check the battery negative cable first thing this evening and report back if that alone fixes the problem, any improvement will be evident as this is happening pretty consistently (especially in stop and go traffic where sudden stops become somewhat patterned, the lights will dim as the truck surges and begins to almost try and stall) i am really believing this to be a ground related issue.

Any help is greatly appreciated,

 

[RayVoy]

The Trailblazers and Envoys have a common interior grouund, behind and below the dash, about mid of dash. The carpet needs to be pulled back to see it.
You may have one in the same place.

 

[Bowtied]

Ray I never found that common interior ground, but a quick tightening of the positive/negative terminal cables did do some good (not all) at improving the problem.

90% of the hesitation and stumbling/stalling at hard/repeated hard stops has gone away. I have not yet to rid the truck of the dimming dash/lights when the windows are rolled up but i feel that this is still a poor ground issue.

I'm either looking at adding a ground, replacing cabling, or a combination of the two plus cleaning the terminals i tightened down last weekend (this coming weekend) to solve the problem.

I believe the "grounding strap" that grounds the engine to the chassis to be located somewhere in relation to the starter. So this weekend im going to go down to that area, bring a wire brush and some water/baking soda mixture and scrub the cables and tighten/torque them to spec. If any are damaged, sheaths torn or altogether freyed/broken im going to replace.

Never found the other "common grounds" i was looking for either.

 

[Chesters]

Bowtied, I am pretty sure you are correct on that ground near the starter and almost sure it is under one of the tranny to engine bolts at the top passenger side of the tranny. Pretty sure that was were one of mine was on a 96 5.7 but I would think be the same. Don't think you could have to many. Ground to frame ground to body, tranny engine. Tough search good luck.

 

[RayVoy]

My daughter had a Sunbird, or a Sunfire, and it had a common ground under the vehicle. I remember it was somewhere near the transmission, but don't remember if it was a transmission to engine bolt. I think it was just a grounding stud, maybe on the bell housing.

 

[xPosTech]

If you're going that far inspecting/cleaning those ground straps then don't overlook the alternator grounding. You might even want to add a supplemental ground between alternator and engine block.

When you finish the grounding you will be half way there. Now do the positive cables alternator to battery to starter.

It's a lot of work but should ease the dimming.

Your battery is in top shape, right? All six cells have correct level of electrolyte? If not use only distilled water.

You shouldn't have to but if you run into any problems do a site search for 'Big Three'.

Good luck.

Ted