Chasing electrical ghost in 2008 Aveo.

[WFWIlson]

Hi all,
This is my first post. I am working on my Father in-laws 2008 Aveo sedan. It has 77000 miles on it. Has been serviced regularly and has always been kept under a carport.
This car is the last one he and his wife purchased together before she died. He is in a wheel chair and no longer drives but wants to keep his car. He is on a fixed income, earlier this year the alternator went out and he had it towed to a dealer, they charged him 600 dollars for an alternator and a battery. It did not need a battery.

About me, I am in my early 50s. Retired Navy and Retired from the electrical/Communications industry. I was a licensed electrician in several states before I retired. I still play with computers and electronics as a hobby among other things (Lionel trains, wood working, fishing and restoring old tools)

the car car has the following problems,
will not shift out of park.
No Dash lights
no daytime running lights
no fog lights.
no chime
parking lights will come on without the switch being turned.
Dash lights come on with no switch being turned or key in ignition.

This may not be a complete list of the electrical problems, these are the ones I have seen happen.

What I have tested and tried.
i checked the break light switch and interlock solenoid, both tested fine. When testing voltage at the solenoid I read. No voltage from the pins on the connector, however I did read 12V from hot pin to chassis. I was able to jump in a test ground and the interlock system worked as it should.

i do have alldata For that car. In looking at the electrical and grounding diagrams I saw only a few common points. Multifunction switch (turn signal switch) grounding and fuse boxes.

i replaced the turn signal switch, it did not resolve the problem, how ever I did find that when I disconnected the battery and reconnected it after I installed the new switch that everything worked as it should for a few minutes. When the systems stopped working I heard the chatter of a relay before it stopped. The chatter was coming from right side under the dash near fuse box. The only relays there are the flash module and the ignition relay. Both of these test fine.

i have tested every fuse and known relay.

This car car does not have the splice pack in the engine compartment fuse box.

i have removed and throughly inspected the engine compartment fuse box, I have checked the passenger fuse box, does anyone know if the interior fuse box is also a lighting or control module?

Does this car have a lighting and or body control module?
according to GM this car was not part of the DLR module recall.

i am open to any and all advice, thanks.
Feel free to ask any questions I may not have covered. I have the drivers kick plate off, the console out, and everything is as aceesable as I can make it without pulling the dash

[Eg.h2o]

No BCM until 2009, but this may explain some of your issues. Many accessories on this vehicle, I think, are switch to ground, with constant hot...if you are from the rust belt, I wish you luck.

[avguy]

.... earlier this year the alternator went out and he had it towed to a dealer, they charged him 600 dollars for an alternator and a battery. It did not need a battery. ....

will not shift out of park.
No Dash lights
no daytime running lights
no fog lights.
no chime
parking lights will come on without the switch being turned.
Dash lights come on with no switch being turned or key in ignition.....

Does your FIL remember which of the things on your list were problems BEFORE it went into this stealership? Also what is the static and running(idling) battery voltage? And have you done load and ripple tests?

[WFWIlson]

Thank you for the replies, after much searching, not a small amount of bleeding and uttering a few curses that I haven’t used since I retired from the Navy i think I have found my ghost. While in name this car does not have a body control module, in practice it very much does. The interior fuse box is a lot more than a fuse box. This car was built in 01/08 if one were to look at the differences between this model , the 07 model and the 09 model, this model has much more in common with the 09. It does not have a stand alone DRL module, it’s functions have been added to the fuse box alone with the cluster lighting, dimmer, and fog lighting. They are switching grounds instead on hot and most cut outs have a reference voltage back to the fuse box.

I understand and the idea that the engineer was going for but it is a huge problem for many reason. Not the least of which is trying to power everything in the car with the exception of the engine from a circuit board that sees the full current flow.

there is no work around that I have found except to bite the bullet and replace the fuse box. Or add a secondary fuse box with the relays needed to take over the failed circuits.

While that is an option I’m not willing to do it. I briefly thought about setting up an arduino controller and going that direction and if were my car I probably would just because. But at this point I am going to find a fuse box or try to have the circuit board in this one reflowed.