Dome lights, steering adjustment, side mirrors, door locks are all inop. I suspect the integration relay has failed so I performed open heart surgery and removed it thinking I’d find something burnt on the circuit board but it looks fine. I guess I should have asked this question before removing it but is there a fuse to protect this relay? ‘91 ls400

 

The interior lights, power side mirrors, door locks, and tilt/telescope steering circuit all share the DOME fuse (some circuits like the mirrors rely on additional fuses too). This is located in the engine bay fuse box

The Integration Relay only works with the car's "illuminated entry system", meaning the dome light and courtesy lights when you open the door. So I wouldn't expect that to be your problem for all of these symptoms

Were you recently changing a bulb with the battery still connected to the car? There have been some threads where owners blew the fuse or even damaged the integration relay by making a mistake when swapping bulbs.

If you find the fuse is blown, make sure you check your bulbs for issues and any wires you can find for shorts/breaks that caused the fuse to blow. Otherwise, you will probably blow the fuse again.

 

Found the CIG fuse in the engine compartment to be the culprit (far inboard fuse). Thx