20 Most Recent
1991 GMC Sierra Questions & Answers
1991 gmc sierra headlights really dim
Bulbs do dim over time but they shouldn't be 'that' dim.
With the engine running. Remove a bulb and use a test meter to test the voltage at the bulb socket, it should be between 12.5 and 13.2 volts.
The with the engine off, test the voltage at the battery terminals. It should be just over 12 volts.
Then test the bulbs with 2 wires to the battery.
Spray the bulb sockets with WD40.
Are the back reflector surface of the headlights in good condition?
Have you polished off any yellowing and dirt from the headlight plastic lenses?
1991 gmc sierra sat for 6 years and won't start
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My oil pressure gauge is high and blowing fuel line fuse in '91 GMC Sierra
check wires from sender make sure they are not broken pinched grounded out i had this same issue with my 89 3500 454 and the wires were rubbing the balancer finally wearing through grounding them this told the computer there was an issue with oil pressure and blew the fuse to prevent engine damage i traced them out and fixed never had an issue again
How do I align headlights on 91 GMC Sierra Truck
As with most all vehicles, there are small set screw around headlight bezel. One or two on top of core support and often one on each side of headlight. Myself usually wait til dusk or darker park on a flat surface and align beam on a wall having vehicle approx. 6 ft. back.
How to reset the timing on a 1991 GMC 5.7
Remove spark plug cylinder #1 place cylinder end of compression time. Crankshaft pulley timing mark at 0 degree
remove distributor cap then find on the cap where is the number 1 cylinder
while placing distributor in place place rotor to face cylinder 1 wire
replace cap and wires
start engine and move dist. to the best rpm then with timing light adjust timing
hope it help
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