Well sence the fule pump is inside your fule tank, you will have to do one of two things. you can go about it by either removing the bed of your truck to get to the top of your fule tank, or use a lift to get your truck into the air, and then unbolt your fule tank *with some sort of jack under it to hold/ease your tank down* then it should be pretty self explainatory from there. take the screws off the cover on the top of the tank, and when you pull out that contraption, you just replace the parts that came with your fule pump and fule filter pump/screen. *the parts should go on the way the used parts came off* then just put it all back together and put the cover back on, rebolt your fule tank. *or if you took your bed off, put your bed back on* and you should be finished. hope this was helpfull.
I have a 1978 Sierra 1500 and mine is near the secondary tank, passenger side of the truck.
The 2014 GMC Sierra-1500 runs on flex-fuel (FFV).
gmc 1500 sierra was fuel injected in '92
no outside fuel filter. inside fuel tank part of pump assy.
Fuel injection
I own a 1990 GMC Sierra 1500 5.7L V8. My fuel filter is located along the frame rail under the cab on the driver's side of the truck. You might look there for the filter on your 1989 Sierra. It's an inline silver colored canister.
The 2004 GMC Sierra-1500 runs on regular unleaded.
The 2001 GMC Sierra-1500 runs on regular unleaded.
The 2008 GMC Sierra-1500 runs on regular unleaded.
The 2002 GMC Sierra-1500 runs on regular unleaded.
The 2010 GMC Sierra-1500 runs on regular unleaded.
The 2006 GMC Sierra-1500 runs on regular unleaded.