No headlights, horn. i have turn signals & brake lights

Replace the turn signal switch. All exterior lights run threw it, except the high mount brake light. The horn also. If the head light switch is on the handle, this should take of it also. If the headlight switch is in the dash, you might have to replace it also if they stay on.

Remove all of your exterior light bulbs, you will most likely find a socket that has been melted or a bulb that has shorted the contacts.

Well, the headlight switch would have no connection to the brake and turn signals. But you could have a ground problem somewhere.
I would want to trace the circuit from the brake switch to the tail lamps with the headlights on to verify.
And does it matter if you are using headlights or just parking lights.

Check the brake light switch (location pedal) unplug the switch & bridge the wires & if the brake lights come on the switch is faulty. all you are doing by bridgeing the wires is bypassing the switch. What is SLS?

Hi!!
Your multifunction switch may be defective. Replace it. $39.99 at AutoZone

• Combination switches operate wipers, directionals, horn, headlights and dimmers.
• When not replaced, wipers, directionals, horn, headlights and dimmer, independently or as a group, will not function or turn off potentially causing safety issues.

Good Luck!! A HELPFUL - 4 THUMBS - rating for this solution would be greatly appreciated. Thank you for using FixYa!!

Hope this helps your out. I know the diagram and locator is a bit blurry but hopefully it gets what you need.
Drivers kick panel:
Front wiper 20A - Front wiper system Cigar 15A- Cigarette lighter Audio 10A- Audio, remote control mirror Air Bag 10A -Air bag diagnostics Stop lights- 15A -Rear brake light, high mounted stop light ECU B+ 10A - Shift lock actuator, transaxle controle module, radio, engine control module Room 10A - Interior light, clock, ignition key reminder, rear cargo area light switch ABS 10A- Anti lock brake system control unit ECU IG1 10A - Transaxle control module, shift lock actuator, ABS control unit, DRL unit Meter 10A - Instrument panel, back-up switch, electronics time control module, inhibit switch Turn signal 10A- Hazard switch ,front and rear turn lights, turn indicator IGN1 20A - Ignition switch ABS 30A- ABS pump motor TNS 30A- Tail light, license plate light COOL/FAN 30A- Cooling fan Cond/Fan 20A- A/C condenser fan Starter 15A- Start signal , Fuel pump Blower 25A- Blower Motor SR/ACC 10A - Ignition switch Hazard 15A - Hazard and turn signal light D/Lock 25A- Door locks ABS 30A - Anti lock brake system control P/W RH 20A- Power window motor right hand P/W LH 20A- Power window motor left hand IGN2 25A- Ignition Switch
Engine compartment :
Head 25A- headlights IG 2 30A- Ignition switch IG coil 15A -Ignition coil, condenser,generator IC regulator, diagnostic connector. O2 down 10A- Rear O2 sensor O2 up 10A- Front O2 sensor Fuel pump 10A -Fuel pump unit Injector 10A -Fuel injector ,camshaft positioning sensor, purge solenoid valve, EVAP, IAC actuator, Mass Airflow sensor, EGR stepper motor. fuel pump relay coil, vehicle speed sensor. A/Con 10A - A/C compressor controls, cooling fan BTN 30A- Brake light , high mounted stop light. Tail light LH 10A- License plate light, tail light , rear combo light, instrument panel illumination Tail light RH 10A-License plate light, tail light , rear combo light, instrument panel illumination Head low 15A- Headlight Head Hi 15A-Headlight Horn 15A- Horn

Inside kick panel

No there not connected, replace the brake light
1999 Chevrolet Blazer Auto Light Bulb Size Guide
Low Beam Headlight Bulb Size: 9006
High Beam Headlamp Light Bulb Size: 9005
Parking Light Bulb Size: 3157
Front Turn Signal Light Bulb Size: 3157
Rear Turn Signal Light Bulb Size: 3057
Tail Light Bulb Size: 3057
Stop Light Bulb Size: 3057
High Mount Stop Light Bulb Size: Assembly
Fog/Driving Light Bulb Size: 880 or 881
License Plate Light Bulb Size: 194
Back Up Light Bulb Size: 3156
Front Sidemarker Light Bulb Size: 194
Ash Tray Light Bulb Size: 161
Glove Box Light Bulb Size: 194
Map Light Bulb Size: 168 or 211-2
Step/Courtesy Light Bulb Size: 168 or 211-2
Trunk/Cargo Area Light Bulb Size: 211-2
Under Hood Light Bulb Size: 93
Instrument-General Light Bulb Size: 161 or 37 or PC194 or PC74
Check Engine Indicator Light Bulb Size: PC74
Hi-Beam Indicator Light Bulb Size: PC74
Seat Belt Indicator Light Bulb Size: PC194
Brake Warning Light Bulb Size: PC74
Automatic Transmission Indicator Light Bulb Size: 194
Directional Signal Indicator Light Bulb Size: PC74
As for the horn, inspect the fuse and relay and most common it would be a bad ground wire or worst a bad horn due to corrosion. Horn will be located in the drivers side fender.
Thank you for using fixya.

ck the wire that comes from starter,,see if it didnt rotted off,,

Below is a listing of which fuse corresponds with which circuit:

1 - 10 Amp - Transmission Controller, Gauges, Autostick
2 - 10 Amp - Right High Beam Headlight
3 - 10 Amp - Left High Beam Headlight
4 - 10 Amp - Radio, CD Player
5 - 10 Amp - Washer Motor
6 - 15 Amp - Power Outlet
7 - 20 Amp - Tail, License, Parking, Illumination Lights, Instrument Cluster
8 - 10 Amp - Airbag
9 - 10 Amp - Turn Signal Lights, Turn Signal/Hazard Indicator
10 - 15 Amp - Right Low Beam
11 - 20 Amp - High Beam Relay, High Beam Indicator, High Beam Switch
12 - 15 Amp - Left Low Beam Headlight
13 - 10 Amp - Fuel Pump Relay, Power Train Control Module
14 - 10 Amp - Cluster, Day/Night Mirror,Sunroof, Overhead Console, Garage Door Opener, Body Control Module
15 - 10 Amp - Daytime Running Light Module (Canada)
16 - 20 Amp - Fog Light Indicator
17 - 10 Amp - ABS Control, Back Up Lights, Daytime Running Lights, A/C Heater Control Cavity Fuse Circuits
18 - 20 Amp - Power Amplifier, Horn
19 - 15 Amp - Overhead Console, Garage Door Opener, Trunk, Overhead, Rear Reading, and Visor Vanity Lights, Trunk Release Solenoid, Power Mirrors, Power Door Locks, Body Control Module, Aspirator Motor
20 - 20 Amp - Brake Lights
21 - 10 Amp - Leak Detection Pump, Low Rad Relay, High Rad Relay, A/C Clutch Relay
22 - 10 Amp - Airbag
23 - 30 Amp - Blower Motor, ATC Power Module
24 - 20 Amp - Power Window Motors
25 - 20 Amp - Power Door Lock Motors, Power Seats

Fuse #8, #18 and #22.

Below is a listing of which fuse corresponds with which circuit:

1 - 10 Amp - Transmission Controller, Gauges, Autostick
2 - 10 Amp - Right High Beam Headlight
3 - 10 Amp - Left High Beam Headlight
4 - 10 Amp - Radio, CD Player
5 - 10 Amp - Washer Motor
6 - 15 Amp - Power Outlet
7 - 20 Amp - Tail, License, Parking, Illumination Lights, Instrument Cluster
8 - 10 Amp - Airbag
9 - 10 Amp - Turn Signal Lights, Turn Signal/Hazard Indicator
10 - 15 Amp - Right Low Beam
11 - 20 Amp - High Beam Relay, High Beam Indicator, High Beam Switch
12 - 15 Amp - Left Low Beam Headlight
13 - 10 Amp - Fuel Pump Relay, Power Train Control Module
14 - 10 Amp - Cluster, Day/Night Mirror,Sunroof, Overhead Console, Garage Door Opener, Body Control Module
15 - 10 Amp - Daytime Running Light Module (Canada)
16 - 20 Amp - Fog Light Indicator
17 - 10 Amp - ABS Control, Back Up Lights, Daytime Running Lights, A/C Heater Control Cavity Fuse Circuits
18 - 20 Amp - Power Amplifier, Horn
19 - 15 Amp - Overhead Console, Garage Door Opener, Trunk, Overhead, Rear Reading, and Visor Vanity Lights, Trunk Release Solenoid, Power Mirrors, Power Door Locks, Body Control Module, Aspirator Motor
20 - 20 Amp - Brake Lights
21 - 10 Amp - Leak Detection Pump, Low Rad Relay, High Rad Relay, A/C Clutch Relay
22 - 10 Amp - Airbag
23 - 30 Amp - Blower Motor, ATC Power Module
24 - 20 Amp - Power Window Motors
25 - 20 Amp - Power Door Lock Motors, Power Seats