BCM Trouble Shooting

[2004 S10]

Hello,
I just joined the site. I searched my problem but I didn't find anything so I thought I start a thread on it.

I'm having an issue with my 2004 crew cab.
Out of the blue a few nights ago when I turned off the truck the headlights and running lights stayed on. I had my buddy scan it and it had a "B1478 Retained Accessory Power Circuit High" code.
I have been checking wires and relays but I haven't found any trouble yet.
I'm thinking it may be the BCM but the strange thing is everything is working as it should with the exception of the lights. last night I turned off the truck and kept the doors closed so the RAP circuit would stay active and as soon as the RAP timed out the radio and overhead console went off and the lights came on. I think it has something to do with the RAP circuit.
Has anyone come across this before?

Does anyone know of a way to check the BCM before I shell out $200+ for a new one?

Thanks for any help.

[00Silverado4x4]

Welcome. I'm sorry I don't really have any suggestions for you except, pull the RAP relay and test it. It may be shorted internally.

[gmtech4]

ya have to follow the diagnostic for that code ,,,,ya need service information to do this and maybe a scanner

 

 

alldata.com will provide this ,for $27 yr ,,,its the only way or its just guessing ,,,make sense ?

[2004 S10]

.

Welcome. I'm sorry I don't really have any suggestions for you except, pull the RAP relay and test it. It may be shorted internally.

Yea, I checked that. I was going to just pull the fuse and forget about it but it still had a drain on the battery.

 

I think I'm getting closer to fixing it. I think it is the ignition switch. I noticed sometimes when I turn off the key with the door open the lights would go off for a split second then come back on so I cycled the switch from run to off several times and sometimes they would go off and sometimes they stay on. I found out if I slowly turn off the key I can make them stay off. (I mean really slow)

A new ignition switch is on order from Amazon. Hopefully that fixes it.

 

Thanks for the reply.

[2004 S10]

ya have to follow the diagnostic for that code ,,,,ya need service information to do this and maybe a scanner

 

 

alldata.com will provide this ,for $27 yr ,,,its the only way or its just guessing ,,,make sense ?

My buddy has scanner that will scan and test etc. but he is really busy now so I want to make sure it isn't something somewhat easy before I bug him to much:)

 

See my reply to 06SerriaZ71 I think I'm close. I hope.

 

Thanks.