possible rear heater blower wheel has broken center hub!
The 1999 Chevrolet Suburban speed sensor is located on the back of the transmission. The speed sensor will be in the upper left-hand corner.
in the back on the drivers side
its at the back of the engine right side of the distributor
The relays have nothing to do with the whining noise, they just complete the circuit and make things work. The whining noise is the fuel pump and that is a common problem with Chevy That noise will not hurt anything, but I would change the fuel filter and that may quite the pump a little. A stoped up fuel filter will burn a fuel pump up.
Under the vehicle, drivers side slightly back of center.
Open the hood. Pull up the "L" shaped rods that go downward on the back side of the headlight The headlight should fall out on it's own. Now unplug the power wire on the inside light bulb on the back side of the headlight. Twist the bulb counter clockwise and pull the bulb out. Push new bulb in and twist to look it in. Plug in wire and put it back in place. Remember to reinstall the rods to hold the headlight in.
After you remove the Transmission oil pan. Just twist back and forth and push it out at the same time. I should come of.
The tail light bulb on a 1999 Chevy Suburban is replaced by removing the retaining screws, pulling the bulb assembly away from the vehicle, and unscrewing the bulb. A new bulb can then be installed and the assembly screwed back in place.
They're very easily gotten to from inside the trunk. You just twist the back of the light assembly until it releases, twist the bulb out, put the new one in and put back into place.
Twist them back and forth while pulling off. Use a dielectric grease when putting them back on. That will save you problems later.
Lift the hood and remove the socket that holds the bulb don't twist to hard they only twist half a turn to release then replace bulb and then put it back into the light assembly
That year must have the 4L60E transmission put back in it, because of the computer system that the truck has in it.