I found this on the site.

https://www.cobaltss.net/forums/how-...ch-mu3-222552/

 

It is really easy to do.

 

It was really easy, once I got my big ass hand down through all those wire looms and crap. If you have the size hand that can palm an Official NBA basketball, stand by for a very tigh sqeeze.

But hell the reverse lights work great now.

 

i need to do this too. i usually just put the car in reverse, waited about 30 seconds and they kicked on

 

I have a 2005 2.2L Cobalt with a 5 speed manual transmission and both backup lights did not work. Both bulbs and the fuse are OK. The following link was very helpful for finding the location of the switch in the Getrag F23 transmission. Remove the left front tire and you will see it: http://www.bluewombat.id.au/opelaus/...%20_astra_.pdf
However, after removing the switch, I tested it and it was OK. I also jumpered the contacts in the transmission and the backups worked.
The problem must have been with the contacts. So I cleaned them and lubricated the rubber ribs in the switch and re-inserted the switch and the lights work fine. They still work after 1 month. So, I assume the problem is fixed. $0 cost.