1986 GMC S15 Service and Repair Manual
This factory service and repair manual for the 1986 GMC S15 works with two gasoline engines — a 2.8L overhead-valve V6 of 173 cubic inches and a 2.5L overhead-valve inline-four of 151 cubic inches — across three two-door bodies and four trims: Base, Gypsy, High Sierra and Sierra Classic. A shorter engine list leaves more room for the rest of the truck, and the manual uses it, covering driveline, brake, steering, suspension and electrical systems with procedures, specifications, torque values, wiring diagrams and diagnostics.
Engines covered
- 2.8L V6 (173 cu in) — OHV, naturally aspirated, gasoline
- 2.5L inline-four (151 cu in) — OHV, naturally aspirated, gasoline
Body styles covered
- 2-door extended cab pickup
- 2-door standard cab pickup
- 2-door cab & chassis
Trims covered
- Base
- Gypsy
- High Sierra
- Sierra Classic
Known issues on the 1986 S15. Three recalls sit on the federal record for this year. One covers replacement lamps built without the amber side reflectors federal rules require; another involves a certification label that could carry tire and wheel information not matching the truck it was fitted to; the third concerns a push-pull headlight switch whose contacts can go intermittent, making the headlights flicker or cut out at night. Three owner complaints are logged, one each on steering, the fuel system and seat belts. The lighting, switch and steering coverage here is where that record points.
TIRE AND WHEEL INFORMATION ON CERTIFICATION LABEL MAY BE INCORRECT.
INSTALL CERTIFIED LABEL WITH CORRECT INFORMATION.
THE PUSH PULL HEADLIGHT SWITCH MAY HAVE ELECTRICAL CONTACTS WHICH ALLOW AN INTERMITTENT HEADLIGHT CIRCUIT CAUSING HEADLIGHT TO FLICKER OR SUDDENLY GO OUT.
REPLACE HEADLIGHT SWITCH AS NECESSARY.
THE VEHICLE ON FIRE. PLEASE EXPLAIN. TT
TILT STEERING AND COLUMN LOOSE. YOU CAN WOBBLE THE STEERING WHEEL ONE INCH. *AK
DRIVERS SIDE LAP/SHOULDER BELT BUCKLE FAILED, WILL NOT LATCH THE SPRING BROKEN. TT
