i want to install an aftermarket HU in my baby, and i was wondering if anyone could please tell me which adapters i need to install it. It an 08 2LT, no onstar or satelite radio. any help will be greatly appreciated. thanks

 

I haven't changed out a radio in a HHR, so I'm not 100% sure. On all of my previous installs I installed a radio wiring harness which plugs into the factory wiring. It makes for a cleaner install and makes it very easy to reinstall the factory deck. On some GM models, I'm not sure about HHR's, an antenna adapter is needed in order to plug the factory antenna into the headunit. Also you didn't mention if you planned on changing out the factory speakers or not. Crutchfield sells speaker wiring adapters that allow you to plug into factory harness same idea as the radio wiring harness mentioned above.
I'd at least do the radio wiring harness, if you didn't want to spend the $ on the speaker harnesses, what I've done in the past is cut off the factory speaker plugs with enough wiring protruding from them that I could splice them back on in the future if ever desired. Hope that helps!

 

i want to use the wiring harness route, i was just wondering if anyone could tell me which one i need, and if there is any other adapters i need

 

According to Crutchfield, an antenna adapter is needed. Those are pretty cheap, around $10-$15. As far as wiring harnesses go, as long as it's for your year/model brand doesn't really matter. There are probably at least a dozen different manufacturers of wiring harnesses. Depends on how much you want to spend I guess.

If you have steering wheel controls and want to use them with new headunit an adapter is required for that as well.

 

I am changing out my HU also. I have an 09 SS with the premium sound system and the bluetooth controls on the steering wheel. The HU I am getting is the Kenwood KNX514 and it has bluetooth but I would like to use the factory BT if possible. What all adapters do I need? A wire harness, steering wheel module, bluetooth/Onstar adapter, antenna adapter?

 

You can use Metra # 70-2104 but you may lose chimes. I believe they started running chimes through the stereo on the 07 models but am not positive.

As mentioned previously, you will need an antenna adapter. I had to use one for a Chrysler (don't remember the part #). Mine was not a min-plug, but another type of interface.

Good luck!
Rob