should there be a ground connection on the back of radio/cd player for my truck.when i turn my in/lights on i here it thru the speaker same with the horn and the radio just makes noise when its low and i step on the gas.is there anything i should check

 

If you have an amp it could be the ground wire to the amp isn't attatched to a suitable grounding stud, or it could be a bad ground through the factory wiring harness, or it could be your signal wires routed too close to power wires.

Start by grounding everything well, ground directly to the battery with a spare piece of wire as a test. Some guys here complain about the ground plane on Pioneer headunits, you don't have a Pioneer do you?

 

no kenwood.but my radio,horn and lights just started all this

 

No he does not have a pioneer. Thread locked. Member already has a thread bout noise in his system.

Here https://blazerforum.com/m_52685/mpage_1/key_/tm.htm