2003 Envoy 'issues'

[TheRick1041]

For the past few weeks..my rear brake lights have been basically shorting themselves out...I can replace them...only to have them burn out 5 minutes...or 1 hour later....

I think that may be the root of the Service engine light staying on...

Well...the other night...driving down the street...the speedometer...just went to zero....car still operating fine...I just don't know how fast I'm going...

 

and then today...speedometer is working...brake lights not...

I make a run to Blockbuster...everything is fine...I head to a Burger joint...and attempt to put the truck in park...it stops short...in Neutral...

I don't realize it right away though...I exit...and go to place my order...and realize my truck is rolling...I pull the emergency brake...and then I realize I can't depress the gear button to move the shifter...

The truck still runs...I can't engage the transmission...

 

so...now I have a 2003 Envoy that I have replace both passenger side power window motors...

I've replaced the gas cap....twice...

and now I have some major electrical and transmission issues...

 

Can anyone offer any tips?

I had the truck towed to the GMC dealership but...they won't open till monday...and if there's any help you guys can give...I can go try it out....

Thanks!