What could it be if my hazard turn signals and break lights are out I've changed the relays and the multi function switch

Doesn't have a turn signal flasher , use's lighting control module .
Turn Signal and Hazard Lamps The turn signal system consists of:

• turn signal miniature bulbs (13465).
• turn signal indicators in the instrument cluster (10849).
• lighting control module.
• multi-function switch (13K359).
• circuit wiring and circuit protection.

Power is supplied to the lighting control module through instrument panel Fuse 6 (10A). This fuse is hot in START or RUN. The lighting control module is connected to the turn signal switch portion of the multi-function switch. Ground is provided to the lighting control module and the turn signal miniature bulbs through Circuit 57 (BK).
Turn signal functions are performed by double filament bulbs in lamp assemblies located next to the headlamps. The turn/hazard function uses the second filament of the appropriate bulb(s).

• With the multi-function switch in the right turn position, power is supplied to the RH front and rear turn signal miniature bulbs and the right turn indicator in the instrument cluster.
• With the multi-function switch in the left turn position, power is supplied to the LH front and rear turn signal miniature bulbs and the left turn indicator in the instrument cluster.

When you had the wiring loose for multifunction switch, if possible, knowing what color wire did what, using wiring diagram, I believe you could have used jumper wire to bypass multifunction switch to see if this or that system would work, if it doesn't, the multifunction switch probably wasn't the problem. On older vehicles it was probably easier to do something like that. Could be issue with wiring in steering column or clock spring, where applicable.Your low beam from dimmer switch goes through drl relay, with relay not energized. At the low beam head lamp, tan wire is voltage, black wire is ground.

Perhaps you need to start with fog light problem I am guessing we do not know for sure the switch was the cause, if you can remove them from the equation. When checking for shorts make sure you check light bulbs to,
Next, since the multi function switch was the next step in your problem solving, I suggest you remove the new switch check out all wires to the connector, be especially careful to make sure none of wires have pulled out or partially pulled out of the connector. Let me know when you finish this then we can move on to continuity testing.
My best guess is the connector as it is common to both your fog light and multi-function switch,
Above all don't let it get to you, these problems can be frustrating but they also can be interesting and fun especially with the right assistant

OK YOU HAVE REPLACED RELAYS AND FUSES ARE GOOD.DOES THIS TRUCK HAVE A TRAILER WIRING HARNESS ADDED TO IT? HAVE YOU CHECKED/REPLACED THE MULTI-FUNCTION SWITCH?

The hazard switch is also the device that supplies the turn signal "flash". If you continue to hear the noise of the turn signal flashing when the turn signals off than the problem is the turn signal switch. It is grounding The purple wire from the hazard switch which makes the hazard switch think the turn signal is on. The fix for this is to relace the turn signal/multi-function switch. Typically they will start to go bad in stages. Your symptom is the first stage. Eventually either the turn signals or the brake lights will also sto working. Let me know if you have any questions and I'll do my best to answer them. Thank you for using FixYa.com!

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

The hazard switch is also the device that supplies the turn signal "flash". If you continue to hear the noise of the turn signal flashing when the turn signals off than the problem is the turn signal switch. It is grounding The purple wire from the hazard switch which makes the hazard switch think the turn signal is on. The fix for this is to relace the turn signal/multi-function switch. Typically they will start to go bad in stages. Your symptom is the first stage. Eventually either the turn signals or the brake lights will also sto working. Let me know if you have any questions and I'll do my best to answer them. Thank you for using FixYa.com!

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

I'd check your multi-function switch (on your steering column, what you touch to turn your turn signals on). There is a small metal clip on the base of it that tells your car to turn the turn signals on (right or left). Also trace the wires from the mulit-function switch to your turn signal relay and see if you're getting power when the switch is activated.

Fix. Turn signals and hazard are on one switch on the dash. Problem is cold solder joints on small board on the switch. First fix I re soldered loose connection on board, worked for a while. Finally simply changed switch with a new one. Take off dash. About 5 screws, pop out hazard switch replace. Problem solved.

Check the multi function switch (turn signal/hazard) . Dirt gets in the contacts and causes your concern.Replace the multi function switch.

I had the same problem with my 2001. I found it was the multi function switch. Better known as your turn signal switch. I found that the hazard switch portion of it had shorted. replacement is fairly easy, aftermarket part is available, much cheaper than GM.