I also posted this on the general forum. hoping to get a response:

hey ya'll, first time posting. I have a 2007 hhr Lt.
I want to remove backup lights and replace them with tail lights. I got new taillights, and got pig tails and sockets at the junk yard. I removed a back up light and before splicing into the wires, thank goodness; I tried the new tail light. WOAH!! IT WONT FIT!!! the backup light hole is smaller than the tail light whole. why? Well it doesn't matter.
I put the backup light back in and went to the golf course.
The question, "Does anyone know the diameter of the 2 holes?" I haven't quite figured how to cut the lower hole to make it larger. I have a Dremel tool but how much larger, didn't really want to take off the tail light to measure. if someone knows it would help a bunch. thanks.

BTW, I'm just a 71 year old who likes to piddle!

 

Welcome to the site - lots of good info here for you.

FYI: Posting in two different forum sections just causes confusion and is frowned upon. the other one has been deleted. - Not a big deal, but please keep it in mind.

I'm not sure what the issue is over this since you already had it apart, and found the new light won't fit. Seems pretty easy to determine the diameter of the hole needed: measure the diameter of the light fixture you are wanting to install.

 

I am guessing that the 2 holes are keyed differently for assembly line convenience. K.I.S.S. If it don't fit, you must quit.

 

Here

https://www.chevyhhr.net/forums/mods...hts-too-28680/

And here

https://www.chevyhhr.net/forums/appe...ght-mod-45102/


Links to the solution of your question


Welcome to the site!

 

Thanks for the 2 forum tip. Didn't know......
Kinda hard to measure with the angle of fixture. Plus had to put it back together in a hurry, cause momma locked her keys in her car at work😀.
Before tearing apart again, thought I'd ask folks for good info Here. I did get a bunch of good answers.