dbarnhart

One of the frustrating things about the unavailability of of a real service manual is the inability to identify things under the hood. For example, what is this (2016 RDX Tech):

rosen39

Take the cover off and send us a picture.
Either additional fuses, circuit breakers, relay or a diagnostic connector.

Look here at Wiring Harness #1

http://acura.bernardiparts.com/Acura/Parts-List.aspx

It looks like the cover is part #40 "Relay Cover"

dbarnhart

I removed the cover and took the photo below. Looks like a relay. Then the next question is 'For what?'

markAZ

Pull it out & see what doesn't work.

Seriously, google-ing the part number seems to indicate it's part of the A/C system, perhaps the compressor relay.

dbarnhart

Thank you. In the 'old days' when my 1993 Mercedes-Benz 300E had an intermittent hard-starting problem, I got out the wiring diagram. I traced the problem down to being one of two relays. I swapped them both out and eliminated the problem.

With no service manual however, that's impossible to do.:-(