Trouble code P1870 means: Transaxle Component Slipping (4T60-E)
Left Front Speed Signal Missing - possibly ABS related - will research more
It is attached to the wiper motor.
Assuming headlights, check fuses. Overheadlights, check override button left side of dash board near odometer.
You need to make sure the tail light assy. is grounded GOOD. Run the water hose around it and make sure it is NOT leaking inside on the board. You may just need to buy a new one from the CHEVY DEALER.
The OBD II ECM (On Board Diagnostic II Engine Control Module) would be found under the hood, on top of the passenger side inner fender.
it is your bulb board. The thing your bulbs go into. Had the same problem. 10.00 bucks
On Board Diagnostic ( two ) I believe the first model year was ( 1996 )
no lights on my 2001 Tahoe radio
if it is like my older model chev truck there is a circut board in the wiper motor assembly, (under the hood), that needs to be replaced. You can get the part at any auto supply store.
It can be either integral with the alternator or be part of the on-board computer.
Look under the dash board near steering column
It is under the hood, on the driver side