BCM? Or many issues? Help?

262 Views 8 Replies 5 Participants Last post by The Banana Goat, 5 d ago

The Banana Goat

Discussion Starter · 10 d ago

Howdy all, over the last few months Ive had more and more electric issues come up. Car is an 04 m6.

1-Windows only roll down an inch unless i hold the switch for 10 seconds, then they roll all the way down. Roll up no problem.

2-Passenger door doesnt lock 50% of the time, honks 3 times to let me know it didnt lock.

3-Car wont crank some mornings, have to cycle the key from start to on a few times and itll start eventually.

4- Randomly lose all power to dashboard while driving down the road. Not often but 2-3 times per month. Will quickly reset and not be a problem.

Any advice and input is greatly appreciated. Just not sure if these can all be traced back to the bcm or just a few. I've inspected the wires behind the glove and theres no indication of wear or damage from the outside, but i havent opened up the cloth covering either.

Save

1 - 9 of 9 Posts

Nothubertjfarnsworth

· #2 · 10 d ago

the first of those sounds like it might be an internal problem to the BCM. iirc, the BCM handles the auto-down window function and has internal relays and some logic to do that. or it could just be the window switch in the center console.

passenger door unlock could just be the lock actuator failing or something physical preventing the lock mechanism from working.

#3 could be ign switch. if it cranks then immediately dies or just cranks and cranks, and you have a flashing theft light on your cluster, could be the key reader ring failing or the key fob nub not making contact.

#4 would need me to do some looking. is it the entire dashboard or just the gauge cluster? 04's are known to have gauge cluster bugs.

Save

slacker

· #3 · 10 d ago (Edited)

My BCM caused cluster problems back in the day. And the bcm does have the window relay in it.

Save

Reactions: 1

The Banana Goat

Discussion Starter · #4 · 10 d ago

Nothubertjfarnsworth said:
the first of those sounds like it might be an internal problem to the BCM. iirc, the BCM handles the auto-down window function and has internal relays and some logic to do that. or it could just be the window switch in the center console.

passenger door unlock could just be the lock actuator failing or something physical preventing the lock mechanism from working.

#3 could be ign switch. if it cranks then immediately dies or just cranks and cranks, and you have a flashing theft light on your cluster, could be the key reader ring failing or the key fob nub not making contact.

#4 would need me to do some looking. is it the entire dashboard or just the gauge cluster? 04's are known to have gauge cluster bugs.

Thanks for the reply, I have swapped window switches, ignition acts like it has no connection until maybe the third or fourth time cycling the switch. Its everything in my gauge cluster and digital displays, radio stays on, ac, engine, just the cluster resets.

Save

Rich-Tripower

· #5 · 9 d ago

For the cluster issues, at the very least I'd try removing the cluster and then reseating the bulkhead connectors. Look for any pins that don't look perfect or are bent.

Save

Reactions: 1

Phoenix

· #6 · 8 d ago

For the lock issue, try cycling the power lovks with the key in the driver's door. Sometimes they get out of sync.

Save

The Banana Goat

Discussion Starter · #7 · 5 d ago

Phoenix said:
For the lock issue, try cycling the power lovks with the key in the driver's door. Sometimes they get out of sync.

My key has never fit my drivers door since owning the car. I know the previous owner got a replacement fob with a blank key. Thanks for the tip though! My fob battery is dying so I need to get a new set. Any advice as far as getting an accurate key cut, or do i look into replacing the driver door lock cylinder as well?

Save

Phoenix

· #8 · 5 d ago

Sometimes the cylinder won't turn if it's not been used in a while.

A locksmith should be able to match the door cylinder to the ignition if necessary.

Unlock the car with the fob, make sure both door are unlocked, and unhook the battery for an hour. Hook it back up and see if that does not get the whole system back in sync.

Save

The Banana Goat

Discussion Starter · #9 · 5 d ago

Phoenix said:
Sometimes the cylinder won't turn if it's not been used in a while.

A locksmith should be able to match the door cylinder to the ignition if necessary.

Unlock the car with the fob, make sure both door are unlocked, and unhook the battery for an hour. Hook it back up and see if that does not get the whole system back in sync.

Nice! Will try this tomorrow. Thanks buddy!

Save

1 - 9 of 9 Posts

Top Contributors this Month