[ruskefamily]

I have a 2002 RSX base with an automatic. It is new to us but has almost 200,000 miles, generally clean, no obvious accidents. It did apparently have an aftermarket remote or alarm or something that I did not get any info about. I have carefully removed all of the aftermarket electrical stuff I could but it changed none of these issues. Basically I have a series of electrical issues that may or may not be related. ALL fuses have been checked and tested.

1. Door locks do not work either in key fob or door switches. I replaced the rear hatch actuator and it didn't change anything. I tested both the new and old actuators with an external source and both work. Checked all fuses, replaced batteries in both key fobs and reprogrammed key fobs as per instructions.

2. When you open the doors, there are no buzzer/bell sounds and the dome lights do not go on. Dome light do work if you manually turn them on.

3. the brake light on the dash is always on. I replaced the e-brake switch and the master cylinder (and fluid level sensor) no changes.

I have read multiple posts on these issues and they seems pretty common but I have not seen that anyone came up with a definite answer to anything. I am debating about replacing the security module box under the dash and/or the remote receiver near the radio and/or the multiplex controller/fuse box under the dash board - but all of these seem to be pricey, difficult and potential wastes of money.....

Any help you can offer would be greatly appreciated.

 

[Perfectionist]

2. Check the door switch on the door frame.

 

[bl817]

all these symptoms lead me to think that there is still a harness from a remote start wired in the vehicle somewhere. if you've taken the "brain" for it out then all the locks/lights/brake pedal switch aren't sending the proper signals to the stock hardware thus they aren't working. from what I remember (15ish years ago at least), some alarms/remote starts use one way electrical gates or valves (I dont remember the proper term) that only let the current flow one way and they are inline to the locks and could be in other circuits. you may have to dig deeper into the dash to see what you find. good luck.

 

[ruskefamily]

Thanks for the feedback. I got ambitious and downloaded the service manual another user on this forum had a link to and I am 99% sure it is the multiplex control unit - everything that doesn't work goes through that unit. That being said - I'll inspect the wires going to and from the unit more carefully to make sure I got rid of everything. All of the problems were there before I removed the aftermarket stuff - but perhaps that is because the aftermarket unit itself failed.... I'll look for a diode (that is the one way electrical bit you mentioned) - I have encountered those before in one of our loaders at work..... I'll also double check the door switch.... I'll keep you all posted - if anyone has any other idea, please share.

 

[ruskefamily]

Just wanted to let people know that it was definitely the multiplex control unit. All of the things that were not working (door locks, parking brake light stayed on, no door buzzer) all worked again after changing to a new (used) MCU..... Now, I appear to be having the same issue with the under hood fuse block. According to the troubleshooting in the shop manual, the fuse block is bad...... i am wondering of someone tried to jump start this thing with a 24 volt setup and fried stuff......