They already checked the ground in the kick panels, no issues there. I'll put that out there first. When you turn the park lights on the turn signal indicators come on dim, the high beam light comes on dim then when you turn the heater on it shuts the radio off, and kills the power port. Any suggestions? They are currently chasing grounds.

 

here is a list of grounds to check.

G100 Ground at starter motor from battery 10-1,151-7, 151-9
G101 On firewall behind PCM 10-1, 151-3
G102 On firewall just Right* of PCM 10-1, 151-1
G103 On firewall near Right* fender 10-1, 151-1
G104 On Right* fender behind battery 10-2, 151-1
G105 Frame 10” below wiper fluid container 10-1, 151-1
G108 On Left* fender at air intake tube 10-2, 151-2
G110 On Left* fender at air intake tube 10-3, 151-2
G200 Behind parking brake KP (DS) 10-4, 151-12
201 Under left center of Dashboard 10-4, 151-14
G202 KP (PS) near CJB (Fuse Box) 10-5, 151-16
G203 KP (PS) near CJB (Fuse Box) 10-7, 151-16
G206 KP (PS) behind & above CJB (Fuse Box) 10-6, 151-16
G300 DS rear cab area 10-7, 151-18&24
G301 DS rear cab area 10-7, 151-18&24
G302 Under front seat DS 10-7, 151-18&22
G303 Behind parking brake KP (DS) 10-8 thru 10-11, 151-15
G400 Under tailgate area DS 10-12, 151-20
G401 Above rear axle on left frame rail 10-12, 151-18&24

Ground Strap See Note 1. This is the engine ground

 

You STILL have a bad ground on the passenger side kick panel.

Look closer....

 

I would definitely check grounds 202 and 203 which are located behind the right-hand kick panel. You'll have to take off the plastic panel below the fuse box which means you have to take off the passenger plastic door sill piece first.

 

and when you take off the door sill piece you will probably find rust.

 

I'm going to nominate "body rot" as the most likely culprit.