possible BCM/SJB issue?

O

optionizerSS

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Oct 31, 2024

#1

• Oct 31, 2024

• #1

So have a 2005 Roush convertible with 38,000 miles. Last week hit the trunk release on my key fob and nothing. Assumed the battery died in it. Started the car and went to put it in gear and no go. All my dash lights were lit up too. Was able to override the shift interlock to get it home but had no lights at all and no radio. Pulled the BCM and saw some corrosion but not alot. Cleaned off everything I could. Put it back together and still have the same problem. Gonna pull it back apart again and look for any other signs. Looked online for another BCM but the ones I have found look worse than mine in terms of how much green 'corrosion' dust. I cleaned it using 91% alcohol, q-tips, and scraped the pins with a butter knife.
Gonna try to bend the contacts back out a little in the plug end to see if that helps. Would there be any BCM codes to read? Any other ideas? Anywhere else I should look? Any good places to find a good used BCM?

 

O

optionizerSS

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Nov 1, 2024

#2

• Nov 1, 2024

• #2

Pulled it back apart tonight. It looks so much cleaner than ones I see on the internet.

 

O

optionizerSS

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Nov 1, 2024

#3

• Nov 1, 2024

• #3

you can see in that last pic there is a terminal in the middle that is the worst

 

O

optionizerSS

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Nov 2, 2024

#4

• Nov 2, 2024

• #4

Checked the terminals today with an ohmmeter. Got a few pinpoint spots with no connectivity even on the same terminal. Meaning both leads on the same terminal. Put it all back together and same symptoms.

 

89ripper

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Nov 2, 2024

#5

• Nov 2, 2024

• #5

I was gonna respond last night to you but i am not exactly an expert on this. One of the traces burnt up? Im trying to remember if there is an issue with these or not. Where are these located? Passenger kick side?

 

O

optionizerSS

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#6

• Nov 2, 2024

• #6

89ripper said:

I was gonna respond last night to you but i am not exactly an expert on this. One of the traces burnt up? Im trying to remember if there is an issue with these or not. Where are these located? Passenger kick side?

Click to expand...

yeah passenger side kick panel. looks brand new other than wear on some terminals. all traces look good

 

89ripper

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#7

• Nov 2, 2024

• #7

How bout the harness end? Sometimes the wires can pull out slightly and might not be able to see.

 

Bullitt347

I have been doing it wrong this whole time

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#8

• Nov 2, 2024

• #8

There should be BCM codes if the BCM is the problem.
If no codes, is it because there is no communication with the BCM?

 

O

optionizerSS

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#9

• Nov 2, 2024

• #9

i have no codes. Would my regular check BCM codes? i always thought you needed a 'special' reader to read BCM codes but seems that isn't the case? Read where i should see a no communication error if the BCM was bad but not getting that error code either.

And checked the plug connector end and can't see anything wrong there. Was gonna ask around if anyone near me has a spare BCM laying around for me to try that and see what happens.

 

89ripper

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Nov 5, 2024

#10

• Nov 5, 2024

• #10

I checked on ebay, they have used bcms, but a bit pricey... definitely wanna diagnose first before getting one. Do you have any water damage around that kick panel area,

 

O

optionizerSS

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Nov 5, 2024

#11

• Nov 5, 2024

• #11

89ripper said:

I checked on ebay, they have used bcms, but a bit pricey... definitely wanna diagnose first before getting one. Do you have any water damage around that kick panel area,

Click to expand...

I don't see any signs of water anywhere but do have some corrosion on a few pins.
Through research I have found that the PCM feeds fuse 4 in the BCM. Fuse 4 then feeds the relay in the BCM which feeds fuse 6. I have power at fuse 4 and my power mirrors work so fuse 4 circuitry is good. I do not have power at fuse 6 so the break is either between fuse 4 and the relay or the relay and fuse 6. I have tested the relay and have also swapped it with a known good one from the PCM so have ruled that out. My next plan is to determine which side of the relay is 'broken' and see if I can visually see what the issue is.
Car is put away till April or May so have some time now to play around with it.

 

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O

optionizerSS

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Nov 30, 2024

#12

• Nov 30, 2024

• #12

Next question...there are many different part numbers for these BCM's, even for all the same year. I have a buddy with a shop that can program the BCM. Can I buy one with a different part number and have him re-program it? This car is a convertible and automatic. Would a replacement have to come from a convertible automatic?
Found a wrecked 2005 Roush convertible at a junkyard online and they were advertising the convertible top parts. I asked about a price on the BCM and the exhaust tips and they said they weren't selling those parts separately? Found another BCM with the exact same part number but they wanted $325 with no guarantees.
So what is the deal with so many different part numbers on these? Can I get a different part number and have it reprogrammed to my VIN?

 

O

optionizerSS

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Dec 1, 2024

#13

• Dec 1, 2024

• #13

K. new information. Just went down to disconnect the battery and try some things but i checked the voltage before i disconnected it. 2.3 volts. Battery is only about 5 weeks old. We initially got a new battery in August but when we had this issue i took the 2 month old battery back to auto zone and it only tested at 65% so they replaced it under warranty. The car has been sitting in the garage since this problem started about 6 weeks ago and hasn't been touched for about 2 weeks. Nothing was left on that would drain the battery. Someone mentioned maybe a fusible link went bad. Any other thoughts based on this info?

 

89ripper

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Dec 4, 2024

#14

• Dec 4, 2024

• #14

A bump for you, I do not know the answer to your bcm question although they tend to be car specific (i.e. convertible, hardtop) Any way you can call a tech line for Roush? Lol probably a dumb question.

As for your battery the only thing I could think of would be to do a parasitic draw test...might be a specific procedure for your car considering all the modules that "wake up" when hoods or doors are opened...

 

O

optionizerSS

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Dec 4, 2024

#15

• Dec 4, 2024

• #15

89ripper said:

A bump for you, I do not know the answer to your bcm question although they tend to be car specific (i.e. convertible, hardtop) Any way you can call a tech line for Roush? Lol probably a dumb question.

As for your battery the only thing I could think of would be to do a parasitic draw test...might be a specific procedure for your car considering all the modules that "wake up" when hoods or doors are opened...

Click to expand...

The BCM is just a Ford part. The Stage 1 is just a GT with Roush bodywork and wheels. But I'm starting to think it might not be the BCM. Will hopefully find out next week. Ordered an ELM adapter and downloaded Forscan so hopefully that points me in the right direction.
As for the battery, I think whatever the issue is is causing it to drain.

 

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O

optionizerSS

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Dec 7, 2024

#16

• Dec 7, 2024

• #16

Did some testing with my multimeter on the OBD port based on a few YT videos I watched. All tests passed so that tells me the terminating resistors are ok (located in the instrument cluster and the BCM) and there are no breaks in the wiring on the main network. So that tells me the issue is more likely one of the modules. And from what I read it may still be the BCM or IC but at least the resistors in them are ok. Whats interesting is I had the IC out right after we bought the car. All of my gauges were acting up so I had to replace all 4 stepper motors on the back of the gauges.
My ELM adapter is supposed to be here Monday so will run Forscan on it after that and will post whet I find.

 

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O

optionizerSS

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Dec 13, 2024

#17

• Dec 13, 2024

• #17

Ended up ordering a BCM off eBay. Hoping it fixes it. I'd be chasing this issue for months so at least I can either fix it or rule that out.

 

O

optionizerSS

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Dec 14, 2024

#18

• Dec 14, 2024

• #18

Well it was the BCM. Ordered one off eBay and it came today. Popped it in and everything works now. Thank goodness. I want to pull it back out tomorrow and open up the case and clean all contacts in case there is any corrosion.
Thanks for everyones input

 

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Noobz347

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#19

• Dec 15, 2024

• #19

I've got one of those El-Cheapo bluetooth microscopes off of ebay that connects to my phone.

Great to have on-hand for such things:

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