I just picked up a 99 accord. From what I understand everything is basically stock except for the headlights are HID conversion and the instrument cluster was replaced with another that had roughly 50k more miles on the odometer.

So here's the issue, I get no feedback response from the keyless entry. I cannot unlock doors using the automatic door locks while the vehicle is off. The courtesy lights on the door work but nowhere else, unless the key is on Accessory (II). This is quite strange as when I turn the car to accessory and close and open the door all courtesy lights then come on, but the instrument cluster thinks all the doors are open and the brake light is out until you engage the ignition to start the engine. Then everything goes back to the way it should be. The climate control settings reset themselves after ignition is turned off and head lights turn off when the key is turned to off as well. Door locks work while ignition is set to accessory or on but at no other time. Very strange, but I'm hoping someone may have some insight to wtf is going on thanks for your help.

 

Poke your head under the dash. Do you see an aftermarket alarm or remnants of one?

 

If an aftermarket alarm is installed(spliced) incorrectly it could be playing hell with the Multiplex control units.

Check all your fuses as well. They should have power on both sides of the terminal.

If the AC is resetting then it may have lost a memory fuse. #13 Fuse(7.5A) under dash passenger side. It is the same fuse for the PCM/Gauge cluster memory. This may have been pulled when diagnosing DTCs or pulled due to a fault and the seller did not want the car to have a memory of DTCs.

Check for a DTC in the AC system. Turn the AC fan to OFF, turn the ignition to II(ON) and the recirculation button to recirculate(light on). Then press the button to FRESH(light will turn off) for ~3 seconds, the lamp will blink any codes that may be stored in the system.

Underhood check #49(15A) fuse for the door lights. Also check under dash Passenger #11(7.5A).

If the vanity mirror lights don't work check underdash Passenger #10(10A sedan/15A coupe)

If the ignition key LED light is not functioning, check underhood fuse #47(20A)