dsr611

Diesel? If it's anything like my '11 Sierra, you'll have the "generic" owners manual and a separate manual for the Duramax/Allison powertrain, also (mine also had a manual for navigation system). If you really want to buy one, you could probably go to the parts department at a dealership and pick one up. Or, look around on Amazon or Ebay and find one. Another route to go, you can always download the manual online and print it off https://my.chevrolet.com/content/dam/gmownercenter/gmna/dynamic/manuals/2014/chevrolet/silverado_2500hd/2014_chevrolet_silverado_owners.pdf https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=2014+chevy+silverado+2500hd+owners+manual&_sacat=34210

Read the 2nd post

OP said Costco parking lot at 6:20

You can start by telling us what year, make, model vehicle you are asking about.

It says "This part also fits...", so according to GM, it will fit older models, along with newer But, I'm with the "check U pull it" crowd...probably get them for a handful of change, if they aren't rotted out. I noticed the other day that the plugs in the door of our 05 Tahoe are falling into the door shell (looks like the outer rim is deteriorated enough that it doesn't hold anymore). You can probably find a generic plug to fit the holes at the local auto parts store

If it's what I'm thinking it is, it's a "Door Shell Plug" https://www.gmpartsdirect.com/oem-parts/gm-door-shell-plug-25652432

There's a "blend door calibration" that can be done. I have it printed out and in the console of our 05 Tahoe. Can't remember the exact steps though. I don't remember if this is it or not, but start here

There's not a member here that has a clue as to what vehicle you're trying to do this in. Mind giving us a clue or do you want us to just guess?

Time to start tracing the wiring...possibly a bad ground

90

Mind telling us what year/make/model the vehicle is? Checked battery cables for corrosion (corrosion can occur under the insulation, not just at the battery connections)? Checked and cleaned all grounds?

Flickering is probably a grounding issue. Locate the gounds and clean. Replace negative battery cable (corrosion is possibly under the insulation). No response from the OBD reader--check cigarette lighter fuse. Cigarette lighter fuse protects lighter, cruise control, and OBD port. Oil pressure issue--get a manual gauge and double check the pressure. With GM trucks and SUVs of that generation (01-06), it's hard to rely on the instrument panel gauges due to the stepper motors used in the gauges. They are notorious for going bad and giving false readings. If pressure is actually low, might want to check pickup tube o-ring

^^^Whagt he said^^^ Cable corrosion can't always be seen and doesn't just happen on the ends of the cable.

Cable on my '10 broke in nearly the same place, but I couldn't tell you the ins and outs of replacing it...dealership replaced it under warranty