Back with my 99 Yukon... So, few things has me looking at relays and I am not 100% on the what and where. First... The AC, looking in the box in the engine bay, there shows a relay on the guide, but the relay isnt actually there... like a previous owner took it out... Im probably opening a can of worms with it... But I want to get a relay in there and see what im working with on the AC... because its 95* and my family whines like you wouldnt believe when its hot. Anyhow... Here is what I have I have no p/n for the AC relay and when I Google it, I get a myriad of different relays. Then there is this one under the dash, behind the parking brake... Secondly... I have been having random PDL issues... some doors lock and unlock sometimes and not others... could be inop one day and good the next... no clear patterns. This is with the original fob, two aftermarket fobs and the lock button on the drivers door... Is THIS the relay for the PDL? Okay, not the best picture... its right side of steering column, above the accelerator... Could be the one pictured below... Any thoughts on that? So its every door that has been affected. Drivers door seems to be the most reliable, but it too has been tricky. Rock auto has the above relay which appears similar to the one I have, and I have yet to find another relay on the truck that looks like this. Is this the PDL relay?