I know this is for F150's but I thought I'd post this even though I have a 2010 Expedition
I had some work done on my 2 front seats and when I got the car back the seat heaters on both didn't work thee was no power to the passenger seat but there was power to the driver seat no power to exterior mirrors and the airbag light is on in the dash.
I know I should get him to fix it but he is a one man show and is clueless as far as electrical issues but a great upholstered.
Has anyone seen this happen before

 

A good diagnosis starts with a thorough visual inspection . We would look for any plugs under the seat that were not plugged in, if all are OK, then would look for what fuses control the heated seats and mirrors. That info would be in the owner's manual.

Let's hope none of the heating element wiring was not shorted in the process. The fuses might hold the answer.

 

Thanks for that I will get him to check the connections u Der the seat and I did check the fuses and they are all good

 

Did you check the fuses in the engine compartment and left side of the dash?

If you find one fuse that is open,before replacing the fuse make sure you determine why it blew.