I have a 07 hhr and it does not have the sub, amp or on star and I was going to replace the factory radio with my aftermarket one But i herd if you use the regular wiring harness that you will loose the sound for your turn signals and the seat belts is this true? Also if I do use the regular harness is that all I will loose is the seat belt and turn signal noise?

 

I beleave that is true. there are some other things you have to add with an aftermarket radio. use the search at the top of the page there is a lot of info on this.

 

Yes you will lose all car sounds. My ls had an aftermarket stereo. It was weird at first but...i got used to it. Your dic should have a gate ajar msg so no worries there

 

Give this thread a read, might have some info that you'll find helpful.

https://www.chevyhhr.net/forums/show...ermarket+audio