Replacing Air Conditioner on a 2003 Winnebago Sightseer

Updated 04/27/2026 | Published 04/20/2026

Question:

Hi I have 2003 Winnebago sightseer. I am looking to replace my rooftop air conditioner. I see a lot of the new ones are plug in. I don’t know for sure if mine is or not. Other than taking the unit off is there anyway to tell?

asked by: Shanon W

Expert Reply:

I can explain Shanon, thanks for reaching out!

Good news is you don’t need to remove the rooftop unit to determine how it’s wired. On a 2003 Winnebago Sightseer you can check from inside by removing the interior ceiling assembly, that's the plastic shroud where the air comes out. The plastic shroud is usually held in place with a few screws.

Once that’s down, look at the wiring; if the unit is plug in, you’ll see a wiring harness plugged into an outlet in the ceiling cavity.

If it’s hardwired, the power wires will run into a junction box with wire nuts instead.

The Advent Air # ADV92SR is a really good option for your RV because it’s a complete replacement system. Instead of trying to reuse parts that may or may not be compatible, this system replaces everything at once. You'll have the rooftop unit, ceiling assembly, and thermostat, so you don’t run into wiring or compatibility issues.

What model of air conditioner do you currently have on the motorhome?

expert reply by: James D

Mark

4/25/2026

I purchased the advent unit from etrailer.com, they delivered it to my rv site. Then I had Time in Season, an rv repair company in Maryville TN come out and install it. They had it in and running in a couple hours plus they installed the heat strips as well. I have had no problems with it and it really does work pretty good. I am happy with both the unit from etrailer.com and Time in Season of Maryville for their quick and professional installation. Sincerely, Mark

James D.

4/27/2026

@Mark Glad we could deliver, enjoy your summer and thanks for choosing etrailer!

Dan

4/25/2026

I’ve had mine for a year self installed worked great last year have not used this year but expect no problems

James D.

4/27/2026

@Dan Nice! thanks for your reply and choosing etrailer

David R.

4/26/2026

I installed the ducted ADV86SR in my 2004 Sightseer last year. I had to run a wire for the remote controller/thermostat from the upper unit to the wall where the original thermostat was located. Since the new AC thermostat is wireless and the original was wired there were plenty of spare wires to choose from. The 12 volt wire was already located where the original thermostat was located. Other than that installation was relatively straightforward. Very pleased with the purchase except a little on the noisy side.