Electrical
What is the Big Three (Big 3) upgrade?
The Big Three upgrade, simply put, is upgrading the main three electrical charging wires in a vehicle's electrical system. These wires are the power wire from the alternator to the battery positive, the engine block to a ground, and the battery negative to a ground.
Why should I upgrade the Big Three?
82-93 S-10 or blazer
12volts red (there will be 2) + ignition harness
Starter yellow or purple + ignition harness
Ignition pink + ignition harness
Second Ignition white + ignition harness
Accessory orange + ignition harness
Second Accessory brown + ignition harness
Power Lock lt. blue drivers kick panel
Power Unlock black/white drivers kick panel
All 82 to 04 S-10s and Blazers take 4x6s in the dash
All 82 to 04 S-10s take either 4x6s or 4x10s in the rear. Just look at it, if its a huge oval, its a 4x10, if its oval but closer to a circle , its a 4x6.
for anyone that is having trouble with bulb sizes
Low beam headlamp
9006LL l
High beam headlamp
9005
Parking light
3157LL
Front turn signal
3157LL
Rear turn signal
3057
Tail light

