EightTrackHits

The old school trouble shooting techniques are good- when you know you have a problem that OBDII can’t help you with or isn’t helping you with. But old school thought on the new systems (or vise versa) can cause us to chase our tails. I thought my truck was giving me grief with regard to the charging system as I viewed the voltage, but it’s been OK. But, the OP may be having a problem.

I’ve had a very similar tick recently. It was a loose spark plug. I thought it was exhaust, but I was looking around under the hood and saw one of the plugs dancing around.

As Swathdiver said, what you are seeing is likely normal. A good description of the charging system can be found in this post from an Avalanche club. https://www.chevyavalanchefanclub.com/cafcna/index.php?threads/lights-flicker.52489/ The checks that Richard mentioned are worth doing if you begin to have problems, but you may be okay. Read the description of the charging system and see if it jives with your symptoms. But please let us know how it goes.

You’ve started with everything that I would start with. Check grounds of course. Check continuity of the harness from the alternator if you have a schematic and a multimeter. I think this issue is a good candidate for a dealer scan. Please follow up and let us know what you find out.

Something like this? https://m.obd2tool.com/goods-1568-GM+Tech2+GM+Scanner+-CANdi++TIS+(Works+for+GMSAABOPELSUZUKIISUZUHolden).html?gclid=EAIaIQobChMI2YX6mPa89gIVA_3jBx1ERQj0EAQYAiABEgLp3_D_BwE

I took the truck to Eastern New Mexico from Indiana and back over the past few days. No hint of coolant loss! Fuel consumption was good for what this thing is, oil pressure was close to 50 psi at around 2500 rpm on the interstate and about 30 psi at around 600 rpm idle after warming up. So, the repair is good this time. I had the oil changed when I got to NM, the mechanic thought something was really leaking due to the fluid film underneath. I’ll follow up if anything noteworthy happens due to this repair.

A good description of the charging system can be found in this post from an Avalanche club. https://www.chevyavalanchefanclub.com/cafcna/index.php?threads/lights-flicker.52489/ Another thing that could cause the flickering is the battery. Just because a battery is charged to 14vdc doesn’t necessarily mean that it can keep providing current under load if it is unhealthy. Of course this could also just be some random electrical component someplace in your truck. My 05 has the works, heated seats, electric fans, nice radio, and I haven’t noticed any flickering. If you’re issue was not intermittent, and you were closer- we could just swap batteries for a bit. If that didn’t work, you could start pulling fuses to non-essential circuits until you noticed the flickering diminish. There is the off chance that it is in one of the control modules.

Yes, the changing voltage levels that you are describing is normal, but the discernible flickering or pulsing of interior lights isn’t. Is that still happening?

By steadily pulse, you mean that the pulsing or flickering is at a fairly constant frequency, correct? Not random?

Is the battery light still on? I had an alternator problem with a Trailblazer, battery light would not go off, connections were tight. I checked continuity of all the connections to their next assembly and found that the wire carrying the pulse width modulation signal (PWM) was open. The fault was fairly close to the connector and I fixed it with a pigtail I cut from a unit in a junkyard. You mentioning pulsing also makes me wonder if it is in the PWM circuitry, but if it is, it is likely not an open PWM wire as that would cause the alternator to give max output all the time. Good luck and let us know. Another member had similar problem, but he never followed up with his fix:

A tech-2 as in one you would find at the dealer? Or are there any clones or other bi-directional scanners that work well?

That's a nice truck, and I really like that color. I'm not too familiar with those interiors, but what is making you want to swap it? My son swapped a grey 2002 S-10 interior for a black one of the same year just because he liked it better. It turned out nice. hardest of course was the dash. A different generation's interior will likely be very challenging. I definitely wish you the best with it!

Exhaust leaks can certainly sound like a tick. And you do have a broken bolt. I’m also of the opinion that if I have a leaking exhaust manifold for whatever reason, I should replace the gasket, because it may have blew out. Then your bracket would make little difference. I’ve listened to noises through a rod to try and diagnose rotational noise. Perhaps it would work for a tick. None of this is an expert opinion though.

I went through a similar situation after replacing head gaskets, only my filler neck turned orange due to Dexcool. I also had water droplets on the underside of the oil cap. The issue for me was a cracked head. Yours may be something else. What vehicle is this issue on? I posted a link to my thread; the title is a little misleading as to why it relates to your issue. I fixed my initial leak, which was a coolant leak between the head and block, but unfortunately during the process, I bought some remanufactured heads to avoid a common crack, and one of those was cracked. Good Luck!

Started a topic on rust protection here: I thought I should let the Midwest Owners Club know, since we deal with a lot of corrosion. Thanks!