grandpalarry777

Out of curiosity, what specifically do you mean about not being "satisfied" with Rotella? Also, which Rotella (T4, T5, T6) were you using?

I have not been notified by GM about this recall but when I check the NHTSA Recall website, my truck is included. From what I have read, the "Fix" that was implemented in the last recall was in itself defective. Thus we are getting the new recall notices. This is similar the to airbag recalls from a couple of years ago where they replaced the Takata airbags with new Takata airbags that were also defective. Good planning and execution at its best. Here is the text from the GM Recall page. Basically it says that they don't have a fix yet. Recall Title: Engine Heater Short Circuit Recall Description: General Motors has decided that a defect which relates to motor vehicle safety exists in certain 2017-2019 model year Chevrolet Silverado 2500/3500 and GMC Sierra 2500/3500 vehicles. In vehicles equipped with the Duramax diesel 6.6 liter engine and the optional engine-block heater cord, a short-circuit condition may develop in the engine-block heater cable or in the terminals that connect the heater cable to the block heater. Safety Risk Description: A short-circuit condition can cause damage to engine components and, in rare cases, start a fire in the engine compartment. Repair Description: GM is working to develop a remedy for this condition, including disabling this feature. Vehicles that have this feature disabled as a remedy to the safety condition will be contacted and offered replacement block heaters and heater cords under a separate customer satisfaction program.

Could it be that the battery in your key fob is getting weak or the fob is failing?

As Jsdirt stated. You need to better isolate the problem before replacing parts. Your mechanic could be correct about the throttle body but he apparently was wrong about the battery. Did he perform any checks on the battery before you replaced it? If not, you might want to find a different mechanic. Not sure how close you are to an Advance Auto, AutoZone, etc but they could have tested the battery and alternator for free. We have all made assumptions about what is causing a problem and thrown parts at it so don't feel bad. Problem could definitely be fuel pressure. Start easy and work toward more difficult/costly things. When was the last time you changed your air and fuel filters? Could be that easy a fix. After the basic filters, have the fuel pressure checked as mentioned before. Could be a failing fuel pump. Also, it would be helpful if you stated what engine your Tahoe has.

You might want to watch a video from the South Main Auto Repair you tube channel. He describes your situation and a possible repair instead of replacing your heater core.

It is part of the MyCar system. Not sure why it is on the vehicle without your knowing about it. https://www.amazon.ca/MyCar-Interface-Module-Remote-Control/dp/B01MQKOBIA

Here is a link to the South Main Auto video mentioned above. Part 1 Part 2

This may be totally out in left field but, did you check the fuel filter housing for hairline cracks? Perhaps a fine crack is letting enough air leak into the system when it sets for a while and you lose prime.

If by 'Wire Identity" you mean that there are different color wires going to the same pin location between the two plugs, it may not mean anything. If both outlets work properly and/or you test the pin-outs and they are the same value (12V, Ground, Active with brake pedal, etc) it probably just means whoever wired the plugs used some extra wire when they were installing them. If you mean that the pin-out values are different (a 12V pin on one measures to ground on the other) I would think whoever performed the installation didn't know what they are doing and you need to have it checked out.

You don't even need to use a diode to get the lights to come on in reverse. By adding a single wire to the BCM under the dash on the driver's side (at least in the 2016 and 2018 HD trucks) you can get the side mirror cargo lights to turn on whenever the truck is in reverse (when the truck is running) or the cargo light switch is turned on (when the truck is turned off). You need to run a wire from pin connector 26 on the Brown BCM block to pin connector 26 on the Pink BCM block (see picture). Following are some pictures of the amount of light put out with this mod.

As pointed out by Ravenkeeper, I misstated the pin number on the pink BCM block. It is correctly pin 26 on both blocks. I have made the correction in the post. This simple modification will cast quite a bit of light toward the back of the truck along the sides...and it's FREE By adding a single wire to the BCM under the dash on the driver's side (at least in the 2016 and 2018 HD trucks) you can get the side mirror cargo lights to turn on whenever the truck is in reverse (when the truck is running) or the cargo light switch is turned on (when the truck is turned off). You need to run a wire from pin connector 26 on the Brown BCM block to pin connector 26 on the Pink BCM block (see picture). Following are some pictures of the amount of light put out with this mod.

While this doesn't directly address adding extra lights to the back of the truck, this simple modification will cast quite a bit of light toward the back of the truck along the sides. By adding a single wire to the BCM under the dash on the driver's side (at least in the 2016 and 2018 HD trucks) you can get the side mirror cargo lights to turn on whenever the truck is in reverse (when the truck is running) or the cargo light switch is turned on (when the truck is turned off). You need to run a wire from pin connector 26 on the Brown BCM block to pin connector 25 on the Pink BCM block (see picture). Following are some pictures of the amount of light put out with this mod.

Greetings from Olathe, KS.