try cleaning your bory to batter ground that is kind of what it sounds like it's try ing to get agorund form wherever the the system tah ais on. check your rear ground for tailights it should hook to theframe in the rear there if it's goot goor ground then they will work. YOu could also have a bulb touching two filaments with headlight on it screws the system up.

hmac300

REALLY SOUNDS LIKE IT COULD BE THE "GROUND THING" AND MAYBE THE "BULB THING" ---AT WORK RECENTLY, AN OLDER PICKUP HAD SORTA SIMILAR ISSUES WITH THE DASH LIGHTS AND SIGNALS

SEEMS PEOPLE "OVER THINK" OR JUST DON'T THINK AT ALL WHEN INSTALLING A "1157 TYPE" BULB

THEY DON'T RECOGNIZE ONE T.IT IS LOWER THAN THE OTHER ON THE BULB--OR WHEN LOOKING IN THE SOCKET THEY JUST DON'T SEE WHICH IS THE HIGHER OR LOWER

NEVER THE LESS--THEY'LL CRAM IT IN ANY WHICH-A-WAY

WHAT WE FOUND ON THE PICKUP, WAS THE SOLDER TIPS ON THE BULB WERE CRAMMED IN THE MIDDLE-----THE SOLDER ON THESE BULB TIPS SOMETIMES GETS "SMEARED OR DISTORTED"----END RESULT WAS ONE BULB CONTACT, WAS CONTACTING BOTH SOCKET CONTACTS-----THIS WOULD BE THE SAME AS THE FILAMENTS TOUCHING EACH OTHER

http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_long-life-mini-bulb-sylvania_5081890-p?searchTerm=stoplight+bulb

OTHER HAYWIRE GROUND RELATED STUFF I'VE SEEN IS WHEN A BODY OR FRAME GROUND BREAKS OR GETS DISCONNECTED---IT GETS NEGLECTED AND NOT PUT BACK INTO PLAY---SOMETIMES THE GROUND FOR THE BODY IS ON THE NEGATIVE BATTERY CLAMP

I'VE SEEN A "BAD" ENGINE GROUND, IN A CABLE CLAMP, ALONG WITH "GOOD" SMALLER GROUNDS GOING ELSEWHERE-------IN THE EXACT SAME CLAMP

UPON ATTEMPTING TO RUN THE STARTER WITH THE KEY-----THE ENGINE "BIG CABLE" GROUND WAS USELESS---SO IT "SEEKED GROUND" THRU THE SMALLER WIRES ON THE CLAMP. THEY COULDN'T HANDLE THE LOAD, SO THEY, AND EVERYTHING TOUCHING THEM GLOWED RED, INSULATION BURNED OFF.......AND LUCKILY THE HARNESS' AND CAR DIDN'T CATCH ON FIRE!

IN THE LINK BELOW--A LOT OF THIS IS INFO YOU DON'T NEED--I JUST SORTA WANT TO GET THE POINT ACROSS THAT YOU MUST BE AGGRESSIVE AND THOROUGH IN CHECKING CONNECTIONS....EVEN SIDE MARKER LIGHTS OR A TRAILER PIGTAIL COULD THROW THINGS INTO A TIZZY

https://www.2carpros.com/questions/1996-chevrolet-tahoe-wont-start-sounds-dead-battery-jumpbox-get-same-reults

KEEP US POSTED ON WHAT YOU FIND-----A VOLTMETER SET ON "OHMS" MIGHT AID YOU DOING CONTINUITY TESTS---WEEDING OUT WIRES THAT SHOULD NOT HAVE CONTINUITY TO GROUND (THIS COULD GET INVOLVED, IF YOU ARE LOST WITH USING A VOLTMETER)

KEEP US POSTED ON PROGRESS

THE MEDIC