Dead spot when turning over

[canadian pipeliner]

Hey, im new to the forum and have a couple questions.  

 

I have a 2008 duramax hd 2500. 175,000 km. (110,000 miles)  It started giving me a few non critical signs a few months ago.  

Lately it has been getting into more critical. 

 

1.  The clock resets when i start the truck. 3 agomonths 

2.  The door locked when i was away from the truck and the key was in the ignition 1 month ago

3.  The heater on drivers side was luke warm and the passenger is hot.  2 weeks ago

4.  When i turn key on it starts to fire then goes completely dead, (no clicking like the battery is dead)  and i kept the key engaged then started fireing again.  Did this 3-4 times then started.  1 week ago

 

I had it to the local mechanics shop and they checked fuses cables and grounds.  cleaned grounds and it still has the same issue.  They put it on there diagnostic tool and could control all the parts for the heater but it still wouldn't blow warm.   I have read forums about gas engines doing funky stuff and it ends up being a door sensor screwing things  up.  Is there something like that out there with the duramax.

 

Thanks for the help!

 

 

 

[swathdiver]

I don't think this is related to your engine, it's a body thing.  Check and triple check the grounds and connectors to the BCM.  Then check the battery positive cable.

 

A Tech2 can see if any codes were thrown with regards to the AC and can control the doors if they're still working.  It can see what the position wants the door at and whether or not the actuator is meeting that or not.  If off more than 5 counts if will throw a code.  

 

If not a ground or positive or negative battery cable, it's probably the BCM.

[jake111]

21 hours ago, canadian pipeliner said:

...

1.  The clock resets when i start the truck. 3 agomonths 

2.  The door locked when i was away from the truck and the key was in the ignition 1 month ago

3.  The heater on drivers side was luke warm and the passenger is hot.  2 weeks ago

4.  When i turn key on it starts to fire then goes completely dead, (no clicking like the battery is dead)  and i kept the key engaged then started fireing again.  Did this 3-4 times then started.  1 week ago

...

I'm not familiar with 2008, but at least ideas from the previous generations...

1. Often low voltage, triggered by big load when starting.  Batteries (even though they still work to start engine) or (sigh) a bad connection or ground somewhere.

2.  I swear it's a secret feature planted into all vehicles for the last 20 years.  I don't trust any vehicle (any brand) not to lock itself, so I always at least roll the window down if I want to shut the door with the key inside.  Call me paranoid but I haven't been locked out since.

3. The blend doors go bad, or they report positions that confuse the computer control, so they go to heat for "safety" (you won't freeze to death).  Mine has always done this a few times a year.  Usually I can just turn the climate control system off, wait 30 seconds, and turn it on and it will reset.  If you cut power to it, then restore power, don't touch climate controls for a few minutes so it can calibrate itself.  You might have hoped GM would have fixed this in later years, but...

4. Hmmm, again a bad electrical connection.  You might replace the ignition switch (not the tumbler, but the electrical part).  The older GMs had problems.  I carry a spare.