I changed the termostat on my 2005 gmc sierra and now it overheated please help

wiring diagram 2005 gmc sierra 1500 Google Search
This should help.

Hello, zenagrin and thank you for asking your question on Fixya!

Here is a simple process that will walk you through a few steps that will pinpoint the overheating problem on your 1993 GMC Sierra, without even using any tools. It has helped millions of people, and I am certain that it will help you, because I wrote it for people in your exact situation.
How to diagnose your overheating 1993 GMC Sierra

Get more great money saving tips and tricks about your vehicle from: twitter.com/acoates23234

Thanks for the vote, and good luck!

Hello cbarrett273 and thank you for asking your question, on Fixya.

Here is a simple process that will walk you through a few steps that will pinpoint the overheating problem on your 1993 GMC Sierra, without even using any tools. It has helped millions of people, and I am certain that it will help you, because I wrote it for people in your exact situation.
How to diagnose your overheating 1993 GMC Sierra

Get more great (money saving) tips and tricks about your vehicle from: twitter.com/acoates23234

Thanks for the vote, and good luck!

stuck thermostat, replace stat

most newer models if no drain plug then take off bottom hose

Could be the thermostat is sticking, or the head gasket is going.

Probably the thermostat.

Yes u do....I have an 03 sierra and apparently they changed everything in 03.....the harness is over $100.....but u need it....and they dont sell a reg wiring kit from 03 and up....if it was an 02, then yes u could get away cheap......it has to do with the steering wheel switches

you need to check you universal joints usualy the one on the rear axel is the first to go. i recomend to put bolth in at the same time. the new ones will be greasable so dont forget to give them a little every oil change