hi i have 1970 gtx .rally dash no power to the radio . the fuss is good . HELP the radio is good thanks

4speed by any chance? The '70 B with 4speed lockout had a problem with the b/u lamps being lit while listening to the radio in accessory key position. My harness wires cooked at this point as the radio connector feeds out to th the b/u lamp harness.
Anyway, radio wire from fusebox is red w/ white tracer and is easy to spot. Check to see if your b/u lamps work. If they do you have power to the radio connector.

yes the car is a 4 speed .and yes b/u don't work how did you fix it thanks

I took my dash harness out, unwrapped it, and found more than one circuit that needs replacing.
Chase down your short if you can. You'll at least need a test light, a volt ohmmeter will work also.
With the key in accessory position check both sides of the radio/ backup lamp fuse. If all is good there, you'll need to pull the harness and unwrap it to find the break and or short. Patch or replace the break/short.
I'm separating my b/u lamp power lead(white wire) and hooking it to the IGN 1 circuit with inline fuse at the bulkhead connector, this way I can listen to the radio in accessory position without the problem.

thank you for the help . i will give you a update

Yo You're hometown- if you need to see up close what's inside your harnesses I'm in the midst of a complete rewiring project. I'm in Lawndale.

The back lights are working. The plug was off at the transmission. I am still working on the radio problem.