I'm replacing my fuel pump in my 99 Suburban. It comes with a new connector to be installed. Problem I'm having is the wire colors are different.The OEM has a gray, purple and 2 blacks, but the new one has O/Blk blk, gray and purple. Which black(or pin number) does the O/Blk go to, and which one does the black go to. I have a manual on order since the cd-rom I bought off of the internet seems to be a coaster now. Any help would be greatly appreciated.

Are you using a AC-Delco /delphi fuel pump?

Unfortunately No. I bought it at Murray's because it came with a lifetime guarantee. I guess there's a small amount of gray area when doing so.

There is agreat amount of problems with the Airtex and other aftermarket pumps.
Run a search on other fuel pump post on here and question parts places.
Carquest has dropped all airtex pumps and went to all Ac-deloc/delphi.
I would take it back and ask for a exchange for a good AC-Delco/Delphi fuel pump.
If not ask for your money back and go someplace else.
Even if it cost a little more and they have to order it for you.

A few pumps and years do have wiring plug in change but the wiring colors should come out.
If not post back
Good luck
MT

Ok .. So I found out that the Orange wire with the black tracer is representing my other ground. I assumed that, but we all know what assuming can do. It appears that it doesn't make a difference as to which black wire ( harness side ) you can connect it to. Thank You for the help. I found this forum, and I see alot of great advice and diag here. So I'll be back. Thank You again for your help. By the way the pump is a Carter P74773M Pump.Thanks Again!

Good Luck.
I hope carter has improved there pumps and now are doing better.
Several years back They used to be real good and then they went to pot.
Then everybody went to airtex.
Same deal.
They used to be good but have also went to the dogs.
MT

Thanks For All the help . I also found out that the O/W wire, I believe is a 18 gauge wire and one black wire ( Harness side & New connector side is 16 gauge ) So make sure that when you stagger the cuts that you match the right wire gauges with each other. So in short . Gray - Gray, Purple - Purple, Black ( 16 Gauge - 16 gauge ) , and Orange with Black tracer - 18 Gauge Black wire ( harness side ) . We'll see how this pump works. Thanks Again!

You are welcome and good luck.
Let us know how it goes.
MT