help w/01 Impala nightmare

Not a Mopar so fingers crossed here...
Anyone who has owned a GM product built between 95 and 05 know about the electrical failures. To make matters worse, this 2001 Impala was once a police cruiser. I'll post pics later.
The person who removed all the add-ons left 5 clipped wires under the passengers front carpet, all 5 hot at switch on. There are smaller add-on wires spliced into the factory wiring from bumper to bumper.
Now I'm aware that the passlock/fail to start problem is typical and probably not related to the add-on crap in this case.
Here's what is making me crazy.. The turn signals dont work but while that switch is activated left or right the hazard/signal flasher module ( it's also the hazard switch mounted in the dash ) makes a stange buzzing noise and the electric fuel pump in the tank starts and runs continuous.
I've googled and read a lot of stuff about the electrical in these cars during the past 8 days and not found a similar fault.
If anyone here has an idea where the problem might be hiding, I'm all ears.
TIA
Author: admin