Is there step by step inst or a video only on replacing the lowbeam headlamp on '99 GMC Suburban?

Sara, 1989 GMC Suburban front bumper removal. Check the attached links,instruction and guides, Good luck
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It depends, if you have sealed beam headlamps, there should be a frame around headlamp, remove it.
If composite headlamps, there are two hex headed pins in top radiator support, remove those pins. Take out lamp assembly so you can get at bulbs.Don't touch new bulbs with bare hands.

You need to check for power and ground at the headlamps I have ran into situations where you think their is a problem with headlamps when just both bulbs have burned out

You need help pushing it down against the O-ring,
while you install the lock ring

if you see no blown fuses check the headlamp relay. there should be a relay box located under the hood

there is to tabs right behinde the headlamp you pull up an can remoce headlight to replace bulb easier. then just twist bulb out an make sure not to touch the new bulb with your fingers. but if your have what they call a sealed beam then there is 4 screws in front of headlight that hold it in.

{: ) For the lowbeam headlamps, check these fuses at the underhood fuseblock:
LO HEADLAMP LT 10amp
LO HEADLAMP RT 10amp
HDM 15amp (main power for the HDM relay. Important)
Voltage is always present at the HDM fuse. When you switch on lowbeams, voltage should be present on the LT and RT fuses. Otherwise check the HDM relay or swap it with another known good and similar relay.
Check the two fuses again for votage:
If voltage is now present, proceed with wiring checks, checking for open wiring going to the bulbs.
If voltage is still not present on the two left and right fuses, but the HDM fuse and relay voltages are okay, you may be having a bad fuseblock.

its the heating element in the seat its brunt out, gonna have to remove seat cover to remove element, good luck.

pedal gets hard when turned of because they are power brakes plus theres no vaccum try bleeding the brakes if theres still a problem check the master cylinder and fluid level when brakes wear down they require more fluid but try first bleeding remember start at pass rear driver rear and pass front and last driver front