[old_master]

Originally Posted by courtroom74

Hi there,

Very nice and detail instructions. I'm new to this forum and newbie from an auto repair perspective as well.
I have a similar problem with a 99 Astro. The fan switch on AC all works except on the last (right most) tic, high. When I switch there, fan is out. Can you let me know if your instruction here would apply to my Astro? Sound like I'm having the relay issue? If you can let me know exactly where it is located that would be great. I can never find a instruction or manual where all the parts supposed to be located. I have this problem "fixed" not long ago (maybe 1.5 years) and it cost me $200. I asked about what was replaced, but I really didn't get an answer so I don't think I'm taking it back again. I rather try to replace it myself if it's "simple" as it indicate here. Thanks in advance.

Post #13 applies to your 99 Astro as well. The modification will bypass the OEM relay and upgrade to a much more substantial relay.